At Welding

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All about SKV Welding(A Complete guide on AT Welding for P.Way Engineers / Officers)


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CONTENTS

1. Course material with Pictorials

2. Circulars & Correction Slips on AT welding

3. Ultrasonic testing of AT Welds

4. Extracts from T-19 Manual

5. Recent developments in A.T. Welding\

6. Salient features of AT Welding manual

7. Check list for inspection during A.T.Welding

8. Training module for AT Welding courses


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Course material

with Pictorials


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1. Need for welding of rails

1.1 Why joints in track?

Indian Railways has about 1,09,000 TKM.

The track structure consists of Rails on sleepers over elastic medium (ballast).

The rails are manufactured in certain definite lengths which used to be joinedtraditionally at site by means of fish plating to form a continuous track. A fishplated joint always being a weak point needs to be eliminated in the

track structure for safe running of trains.

Joints however are inevitable and cannot be completely eliminated as we cannot manufacture the rails for very long and indefinite lengths aso The transportation from plant to site becomes very difficult.o It is difficult to cool longer rails in controlled conditions at plant.

1.2 Disadvantages of fish plated joints

Cause discomfort to passenger due to noise and poor riding quality.

20% additional energy will be consumed on fish plated track

Holes in the rails will reduce the strength of rails.

At higher speeds maintainability is difficult.

These are prone for sabotage as fishplates and bolts can be removed easily bymiscreants.

To overcome these drawbacks, rails are to be manufactured in longer lengths to

the extent possible and joined by welding them.

1.3 Present status of rail manufacturing

In India rails are manufactured and supplied by Bhilai steel plant alone.

Rails are now manufactured in lengths of 13m & 26m, 65m & 78m.

Future plans are to manufacture rails upto 480m length.

Even if it is possible to produce longer lengths of rails, joint becomes a must

at points and crossing location.


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2. Rail Welding

2.1 Types of rail welding There are four suitable methods of welding for rails :

1) Flash butt welding

2) Alumino thermic welding

3) Gas pressure welding

Out of these three methods as mentioned above, only first two methods are the

most widely used methods for welding of the rails amongst various countries

of the world.

The Alumino-thermic welding is also referred to as Thermit welding.

Flash butt welding is normally done at plant and the AT welding is done at

site.

2.2 Alumino Thermic welding

Alumino thermic welding is a process that causes fusion of metals by heatingthem with superheated molten metal from an alumino thermic reaction

between a metal oxide and aluminium.

The alumino thermic process is extensively being used world over for joining

the ends of the rails.

On Indian Railways Alumino thermic welding with short pre-heating process

called SKV welding is used for welding of rails of different chemistry and

sections.

2.3 Advantages of SKV welding

It is possible to do it at site under field constraints with reasonable quality.

It is used to weld flash butt panels of 3 rail/ 10 rail/ 20 rail panels into long

panels.

Most suitable for taking up repair work of fractures and isolated welding.

No pressure application is required and needs normal surface preparation

compared to other types of weldings.

3. Principles of Thermit Welding and its Formula


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After exothermic reaction lasting for few seconds, approximately equal

volumes of molten steel and liquid Al203 are separated at a temperature of

about 24000C.

Al203 (slag), being lighter, floats on top of the molten metal.

Ferro-manganese is added to the mixture together with pieces of mild steel to

control exothermic reaction to match wear resistance of thermit steel to that of

the various grades of rail steel to be welded.

Fe2O3 + 2Al = Al203 + 2Fe (25000C, 43.2 K Joules).

3.2 Process of AT welding

RDSO has issued a Manual for Fusion Welding of Rails by the Alumino-

Thermic Process.

The alumino thermic process is to apply it for joining two pieces of rail, end to

end, by casting molten steel into a refractory mould that has been placed

around the spacing between the two rails.

The ends of the rail must be straight and the correct welding gap established. The rails must be properly aligned with faces free of rust, dirt & grease.

The rails must then be preheated sufficiently to provide conditions for

complete fusion between molten steel and the base metal of rails to be welded.

Prefabricated moulds are fixed and joints are filled with luting sand.

The thermit reaction is carried out in a conical metallic shell lined with

magnesite, called crucible, prior to tapping into the moulds.

The weld must then be cooled prior to allowing any traffic hydraulic rail

tensor if used during the welding.

3.3 Reference documents for Quick thermit welding with short pre-heat (SKV

process)

The thermit welding with short pre-heat (SKV), despite all the improvements,

still requires great care by the welders and supervisors during execution.

For executing good quality welds, following documents should be referred to;

Indian Railway Standard Specification for fusion welding of rails by

Alumino-thermic process (IRS-T-19-1994).

Manual for fusion welding of rail joints by the alumino thermic process

(Printed in Sept 1998) read with C S No 1 to 5


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4. Thermit Welding Equipment and Accessories

QuantityS.No. Description

Mass Welding Repair Welding

A Pre-Heating Equipment

A1 Air-Petrol pre-hearing

1.Pressure tanks with pressure gauges

complete2 Nos. 1 No.

2. Vaporisers (burner) complete 2 Nos. 1 No.

3. Nozzles prickers 4 Nos. 2 Nos.

4. Nozzle keys 1 No. 1 No.

5. Vaporiser stand 2 Nos. 1 No.

6. Goose neck attachment to vaporiser 4 Nos. 2 Nos.

A2. Compressed air-petrol pre-heating

1. pressure gauges 2 Nos. 1 No.2. Torch (burner) complete 2 Nos. 1 No.

3. Torch (burner) keys 1 No. 1 No.

4. Torch (burner) stand 2 Nos. 1 No.

5. Goose neck attachment to vaporiser 4 Nos. 2 Nos.

A3. Oxy-LPG pre-heating

1. Oxy-LPG torch (burner) 2 Nos. 1 No.

2. Oxygen cylinder with pressure gauge 2 Nos. 1 No.

3. LPG cylinder with pressure gauge 1 No. 1 No.

4. Torch (burner) stand 2 Nos. 1 No.

5. Connecting hose pipe 4 Nos. 2 Nos.

B Other Equipment

1. Crucible complete 2 Nos. 1 No.

2. Crucible caps 2 Nos. 1 No.

3. Crucible forks 2 Nos. 1 No.

4. Crucible stands 2 Nos. 1 No.


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QuantitySl.

No.Description


10. Straight edge 10cm long 2 Nos. 1 No.

11. Aluminium steel rod for thermal

plugging2 Nos. 2 Nos.

12. Leather washers for pump 4 Nos. 2 Nos.

13. Gap gauges and height gauge 2 Nos. 1 No.

14. Filler gauge 2 Nos. 1 No.

15. Tools for punching the marking 2 Sets. 1 Set.

16. Mould shoes 6 Pairs 2 Pairs

17. Stop Watches 1 No. 1 No.

18. Pyrometer/ thermal chalk for

measurement of rail temperature1 No. 1 No.

19. Wooden wedges for rail alignment 24 Nos. 12 Nos.20. First aid box filled with medicines,

bandages, cotton etc.

1 No. 1 No.

21. Mirror 150 X 100 mm with handle 2 Nos. 1 No.

22. Tool box containing :

(i) Hot sets (chisels) (For

emergency use only) 2 Nos. 2 Nos.

(ii) Funnel tin (for pouring petrol) 1 No. 1 No.

(iii) Adjustable spanner 1 No. 1 No.

(iv) Hammer 1 kg 1 No. 1 No.

(v) Sledge hammer double panel 5

kg2 Nos. 2 Nos

(vi) Steel wire brush 1 No. 1 No.

(vii) Blue goggles 2 Pairs 1 Pair

(viii) Paint brush 50 mm 1 No. 1 No.

(ix) Slag container (bowl) 2 Nos 1 No


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QuantitySl.

No.Description


23. Weld trimmer 1 No. 1 No.

24. Insulation hood for control cooling

(for 110 UTS rail welding)

1 No. 1 No.

25. Rail profile guided grinding

trolley

1 No. 1 No.

26. To ensure quality, protectiveclothing, shoes gear & leather

gloves


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5. Storage, Preservation and Handling of Portions & Moulds

The portion being hygroscopic in nature, will have double packing, first in a

polythene bag and then in a cloth bag. Damaged/torn polythene bag may

result in moist/damp portion and should not be used.

Once portion absorbs moisture, the same cannot be removed even by drying

as ingredients react chemically. All such portions should not be used for

welding.

Therefore suitable storage condition for portion & mould to avoid contact

from moisture is to be made. These should be stored in water tight stores kept

0.3m away from wall and 0.5m above Ground to avoid ingress of moisture.

The acceptance slip for the portion given by the RDSO shall be found inside

the bag. RDSOs seal should be available on top of the bag. The portion

should conform to IRS-T-19-1994.

It should be ensured that the portion to be used must match the rail section,

grade of rail and the welding technique.

The portion should be poured into the crucible through fingers with a

spraying action and striking the crucible wall so that the bottom plugging

remains undisturbed

After filling, the portion should be heaped at the center of crucible and a small

recess made at the top into which the igniter can be placed

Portion should not be mixed with any foreign material or any amount of

additional portion.

The crucible cap should then be placed in position and an igniter (sparkler)

hooked on to the crucible cap ready for use.

Particulars of portion contained in the acceptance slip such as Batch No.,

Portion No., Date of Manufacture, etc. should be recorded in a register kept

f hi


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If packing is intact and there is no entry of moisture, the portion can be used

even after a long time. However, if they need to be used beyond two yearsafter the date of manufacturing, following procedure is to be adopted for

permitting use of portions.

(a) One random sample per batch of 300 or part there of may be drawn from the

portions available in stores.

(b) The sample shall be tested for reaction test. If reaction is normal, batch

represented by the sample can be used without further tests.

(c) In case the reaction is found to be quiet or boiling, a test joint should be made

from one more sample selected from the batch for conducting Aluminium content

test and Load deflection test.

(d) The above tests should be conducted at Zonal CMTs organization and / or the

Flash Butt Welding Plant. If values obtained in the above tests are within the

specified values as given in Para 4.1.3 and 4.2.3.1 of IRS: T-19-94, the batch

represented by the sample can be used, otherwise batch should be rejected.

(e) Rejected portions are to be disposed-off by igniting five portions at a time in a

pit away from the store.

Moulds

Only prefabricated moulds supplied by the portion manufacturer shall be used

for welding.

Moulds are made by mixing high silica sand to IS: 1987 with sodium silicate

to the required consistency, followed by passage of carbon dioxide gas.

These prefabricated moulds shall have adequate permeability for escape of

mould gases and adequate reinforcement to avoid mould crushing during

transportation and welding.

B f ti th il d t b ld d h i f ld h ll b


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6. Thermit Portion

Portion is a mixture of different materials when melted forms the material of

type rail steel designed for doing one weld.

The portion used for welding shall conform to the technical requirements as

mentioned in IRS : T-19-1994.

The suitability of the Portion for the welding process in respect of the type

and section of rails to be welded shall be ensured before commencing

welding.

Different main ingredients used in manufacture of AT portion are

o Mill scales

o Aluminum

o Ferro-manganese

o Steel chips

o Silicon carbide

o Ferro vanadium

o

Flour spar The proportion and quantity of the same depends upon the type of rail section

and type of welding and is the trade secrete of the manufacturing company.

Only RDSO certified/passed portions should be used for welding.

In India, though many labour contracting firms are approved by RDSO for

executing AT welding with portion and technique developed by Thermit

Portion Plant, N. Railway, Luknow, only 4 firms are approved for

manufacturing of portions and execution of welding. they are India Thermit Corporation Ltd., Kanpur.

Harshad Thermite Industries, Raipur.

Sagar Electrical and General Industries, Hyderabad.

Raybon Metals Private Limited, Bilaspur.

7. Inspection of Rails before Welding

It should be ensured that the end bends of rails are within +0.5mm, -0mm in

vertical and +/_ 0.5mm in lateral direction with 1m straight edge.

The new rails/ Old rails to be welded shall conform to the tolerances specified

in Table 1 and Table 2 ofManual for thermit welding

Old rails :


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iii) Observation of the entire preheating process to ensure that rail end(s) is not

melted and there is no breakage of the mould. In the event a portion of the rail

head or rail face of either rail end is melted, the weld must not be executed.

Rail ends and moulds must heat evenly. Uneven heat can cause internal

cracking of the weld due to uneven cooling.

During the preheating process, a fairly usual occurrence may be the breakage

of the mould. This is where a piece of the mould may break off and fall into

the weld cavity. In the event this happens, welding should be stopped, the

mould should be removed & disposed off properly and new mould installed.

14.2 Pre heating equipment

Air Petrol Burner

Compressed Air petrol blower

Oxy-LPG heating system

14.3 Preheating time & pressure

Preheating time: Preheating time would be about 10 to 12 minutes and 2 to

2.5 minutes for air-petrol and oxy-LPG preheating techniques respectively.

Preheating Pressure:70.70 kg/cm2 in welding process using air petrol

burner In case of pre heating by oxy LPG process, pressure for oxygen and

LPG cylinders shall be adjusted in the range of 7.0 8.0 kg/ cm2 and 2.0-2.5

kg/ cm2 respectively. While preheating with oxy LPG burner, LPG supply

should be opened first,ignited and thereafter oxygen supply should be opened.While closing, oxygen supply should be stopped first followed by LPG

supply.

Control over heating time: By stop watch or by temperature measuring

devices like optical pyrometer, contact type pyrometer or temperature

indicating crayons may be used for measuring rail end temperature.

15. Maintenance of Crucible

The crucible lines with refractory material should be preheated from inside to

remove moisture with the preheating torch before making the first weld.

Preheating should be done from top to bottom.

Failure to properly dry the crucible may cause


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The molten metal is then tapped into the mould by pushing up the closing

pins shank with the tool provided for the purpose. The crucible should not

move during tapping and no turbulence should occur while pouring.

In case of occurrence of boiling or vigorous reaction, because of moisture

content in the portion or crucible, the metal should be tapped outside and not

in the mould.

Off center pours will cause defective welds due to slag inclusion.

Welding staff shall wear welding gloves and welding goggles.

During the initial violent phase of the reaction, all welding staff must standclear.

16.2 Tapping time

Tapping time is defined as the total time, from the time the portion is ignited,

till the molten weld metal begins to pour into the mould cavity. Tapping time

is very important for the final weld quality.

Premature tapping can cause a high aluminium content in the weld metal withpossibility of slag inclusion too.

Delayed tapping, on the other hand, causes loss of heat from the molten metal

with the risk of lack of fusion.

The optimum tapping time is 20-23 sec which is Reaction time + Waiting

time( For slag to rise on molten metal).

16.3 Mould waiting time

It is the time the molten metal shall be allowed to cool and solidify after

pouring with mould intact for the stipulated time.

It depends upon the rail section and ambient temperature.

The mould waiting time is generally 4-6 minutes for 25 mm gap joints and 12

minutes for 75 mm gap joints.

The mould shoes shall be removed just prior to completion of mould waiting

time.

16.4 Chipping of weld metal

On completion of pouring, the crucible is lifted off and slag bowls removed


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In case of welding of old rails, if it is not possible to use weld trimmer due to

flow of metal at rail head, manual chipping should be done.

During the trimming operation, it shall be ensured that the wedges used inaligning are in their proper places without loosening, and they are not

removed for a t least 20 minutes after stripping.

With the use of hydraulic weld trimmer, mould from the top and sides is

removed leaving at least 1mm excess metal on the rail table for removal

during final grinding.

The runner and riser must not be removed until cold, and that too only byknocking towards the rail.

16.5 Importance of risers

The side holes of the moulds are called risers. Slag comes out from this.

The risers are basically designed to allow slower rate of cooling of the weld

metal to form Pearlitic structure ( fine grained with high fractured toughness)

Lower UTS rails are less susceptible to heat than higher UTS rails, hence forthe same welding type, lower UTS rails form a better joint

16.6 Grinding

Finish grinding of rail top and sides should be carried out by profile grinders.

Use of hand files should not be resorted to.

Grinding should commence only after removing the wedge kept for joint

alignment and putting back the fastenings.

Final grinding should be done to the original profile of the rail as per the

dimensional tolerances prescribed in the Manual on Fusion Welding of Rails.

The accuracy of grinding shall be checked by using 10 cm straight edge.

While grinding, only light pressure should be applied and grinding wheel

should be moved to and from to avoid local over heating.

The best finish grinding on the running surface of the rail head can be

achieved when the weld has completely cooled to ambient temperature.

No welding shall be carried out if it is raining. In case, the rains start while the

joint is under execution, immediate arrangements to adequately cover the site

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The first train should be allowed to pass on the newly welded joint only after

30 minutes have elapsed since pouring of weld metal. Necessary speed

restriction shall be observed until the grinding operation is over.

17.3 Precautions for newly welded joints:

Before the passage of traffic, the wedges used for aligning should be removed

and joint sleepers which were shifted to obtain the clear gap of 250mm on

either side shall be re-shifted to the original location and repacked.

The newly weld need to be tested by USFD at the earliest

Till tested as good by USFD, the weld done in situ shall be joggle fish platedwith two clamps.

Painting of weld collar should be done on all welds to protect them against

corrosion immediately after the welding.

18. Marking of Joints :

Each joint shall have a distinctive mark indicating month, year, agency,

welders code and weld number of the welded joint.

This should be done by punching on an aluminium strip of suitable thickness

and dimension of 30 X 100 mm which should be fixed to the web of the rail

with epoxy adhesive at approximately 300 mm from the joint.

The welded joints shall be serially numbered in a kilometer.

Repair welds/additional welds done at a later date may be given continuing

weld number in that kilometer. For example, the last thermit weld umber in aparticular kilometer was 88 and subsequently a thermit weld has been

executed, it shall be numbered 89, irrespective of its location in that kilometer.

PWI shall maintain Thermit Weld Register as per program given in

Annexure 5 of Thermit welding manual.

No punch marking should be done on the rail.

19. Heat Affected Zone (HAZ) :

It is the length of rail affected by fusion from center line of weld.

For normal SKV welding of 25mm+/-1mm, The fusion Zone is 45mm and the


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Fixing of Responsibility for failure of weld is based on the HAZ. Normally a

failure occurred with in 100mm from center line of weld is considered as weld

failure. And the one beyond 100mm is considered as rail failure.

20. Frequency of In-service Painting:

Once in 4 years in areas not prone to corrosion.

Once in a year in corrosion areas.

On conditional basis in areas prone to severe corrosion.

21. Acceptance Tests on Welds :

21.1 Visual inspection

All the welded joints shall be examined carefully to detect any visible defect

like cracks, blow holes, etc. Any joint, which shows any visible defect should

be rejected.

21.2 Dimensional check:

All finished joints shall be checked for dimensional tolerances which shouldbe within the tolerances.

(i) Vertical alignment : Variation not more that +1.0 mm, -0 mm measured

at the end of one metre straight edge.

(ii) Lateral alignment : Variation not more that +0.5 mm measured at center

of one metre straight edge.

(iii) Finishing of top surface : +0.4mm, -0mm measured at the end of 10cmstraight edge.

(iv) Head finishing on sides : +0.3mm over gauge side of the rail head

measured at the center of 10cm straight edge.

21.3 Ultrasonic flaw detection test :

All the fusion welded joints shall be ultrasonically tested and accepted by the

purchaser or his representative as per the Procedure for ultrasonic testing ofthermit welded rail.

Subsequently USFD testing of A.T. welds shall be done as per the provisions

given in Manual for Ultrasonic Testing of Rails and Welds (1998).

21 4 Rewelding of defective joints


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21.5 Sample testing of joints

One out of every 100 joints welded shall be selected at random and should be

got tested within one month of welding for its hardness, transverseload/deflection tests and porosity.

If the sample test joint fails to satisfy any of the requirements of specification

two more randomly selected joints from the same lot of 100 joints shall be

subjected to retests and both the joints should clear the tests.

If this report is also not satisfactory, further welding of joints shall be

suspended until the firms welding technique has been examined certified byRDSO.

21.6 Guarantee

Rail joints welded by a firm shall be guaranteed against failure for a period of

two years and if fails within the guarantee period shall be rewelded free of

cost by firm.

In case of failure of sample test joint, the period of guarantee for 100 joints

represented by the sample joint shall be extended for a further period of one

year

The welded joints with the extended period of guarantee shall be marked X

with yellow paint on the outer side of the web of the rail near the joint

21.7 Other requirements

Welding shall be supervised by trained welding supervisor and carried out by

trained welder having valid competency certificate from RDSO/TPP/NR,Lucknow

A welding supervisor shall supervise not more than two welding teams

deployed within 50m distance at a time.

A copy of the thermit welding manual shall be available with each PWI and at

each welding site


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22. A.T.Welding Defects, Causes & Remedial Measures

The major types of defects which can cause weld failure because of improper

weld execution are given under.

1. Longitudinalcrack in rail web

Cutting of war resistantgrade rails by flame

cutting.

Flame cutting of rail endsis prohibited due to

likelihood of cracking inweb.

2. Lack of fusion inrail foot

Flame cutting of railends

When producing thewelding gap, never flame

cut rail ends without usinga cutting glued.

3. Cold spot lackof fusion.

Gap between rail endstoo wide-rail ends

outside the collarformation.

Maintain the welding gapbetween rail ends specified

in the approved parametersof the technique. Never

attempt to weld a gap,

which is too wide, withstandard mould.

4. Cold spot lackof fusion and

associated localporosity.

Mould fitted verticallybut off centre to the

web gap.

Take care to centralize themould to the gap. Never try

to fit both mould halvessimultaneously.

5. Lack of fusion onfoot of one rail

end.

Mould fitted center tothe gap but inclined to

the vertical.

Take care to fit mould bothvertical and central to the

weld gap. Do not inclinemould to the vertical.

6. Gross lack offusion on rail end.

Standard mould fittedto rails of dissimilar

depth.

Do not try to weld worn tonew rail, or rails dissimilar

depth with standard mould.

7. Porosity in the

thermit steel

Luting sand too wet. Luting sand must be moist

but not too wet. Never usewet luting sand.

8. Sand inclusion inthe rail foot and

sand burn markstransversely

across the rail

Dropping of luting sandinto the mould.

Take care when sealing themould with sand. It must

not be allowed to drop intothe mould.


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10. Gross porositythroughout the

whole weldsection.

Use of damp portion.Moisture present in

portion reacts withaluminium and in its

characteristic, thereby affecting the thermit

reaction and resultantsteel. This change

cannot be reversed bydrying out.

It is essential only to usedry thermit portions. Never

use portions, which havebeen damped and dried out.

11. Gross inclusionof slag in the railhead.

Pouring without theplug in the position. After preheating, fit thesand core with the riseraperture of the mould and

press down lightly.

12. Gross slaginclusion in rail

head on one side.

Pouring off centre tothe plug.

Ensure that the crucible ispositioned centrally over

the sand core and the

crucible does not moveduring the thermit reaction.Never allow the thermit

steel to pour directly intoeither pouring gate.

13. Fracture throughweld centre.

Immediate impositionof tensile forces on

weld metal cause

internal tearing of weldmetal which leads tototal transverse

fracture.

During solidification andimmediately after thermit

weld should not be

subjected to tensile force.

14. Cracking of weld

after cooling atrail ends.

Failure to use the

correct thermit portionand welds. Procedure

as approved for specific

rail section/railchemistry.

Always check the

chemistry and type of railto be welded and use

correct type of portion and

adopt correct weldingparameters at the time ofwelding of rail joints.


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23. Precautions to be taken During SKV Welding

While carrying out welding at site, the following precautions shall be

observed:

(i) It should be ensured that the portion being used matches with type andchemistry of rail.

(ii) Rail ends should be square.

(iii) Alignment of rail ends should be perfect as checked by straight edge.

(iv) Rail ends should be properly cleaned with kerosene oil and wire brushes.

(v) Stop watch should be provided to the welding supervisor at each weldingsite.

(vi) Pressure in the tanks/cylinder should be properly maintained during pre-heating.

(vii) Correct gap between rail ends at head, web and foot shall be ensured.

(viii) Correct preheating time for rail ends shall be ensured.

(ix) Tightness of clips fitted with hose connections to compressor tank andburner shall be checked before commencing preheating.

(x) Nozzles of burners shall be cleaned periodically to avoid back fire.

(xi) The compressor tank shall be kept at least 2 to 3 m away from the burnerto prevent fire hazard.

(xii) The tapping shall be done within the time specified for that particulartechnique. Welding parameters for techniques presently being used areavailable at Item No. 25. For special type of welding i.e. 75mm gap,

combination joint, etc. the time of reaction and tapping shall be asstipulated by RDSO for that particular welding technique.

(xiii) Arrangements for giving first aid shall be available at site.

(xiv) Welders should be provided with gloves and coloured glasses.

(xv) Boiling portion shall be out tapped.

(xvi) No moist portion/torned portion bag shall be used for welding.

(xvii) Dampness in moulds can lead to Porosity and early fatigue failure ofwelds.


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24. Parameters for different gaps of A.T. Welding Techniques


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24.1. Dimensional Tolerances for finished AT Welds


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25. Alumino Thermit Welding - Dos & Donts

25.1 Dos

Welding is to be done only in adequate traffic block.

For doing cess welding, rail should be supported on a minimum of

10 wooden blocks duly pegging the rail for better alignment.Welding is to be done either insitu or on the cess, but not on the

ballast shoulders.

Battered / hogged rails are to be end cropped before welding.

Rail ends should be cut true to square.

The rail ends should be cleaned with K.oil before welding to

remove dust, grease particles.

Fittings for a minimum of 5 sleepers on either side are to beremoved for alignment and levelling.

Welding gaps should be as specified for that type of welding.(25mm/50mm/75mm)

Rails are to be properly aligned before taking up welding.

Moulds utilized for welding should not be cracked or wet.

Dry moulds should be fixed centrally on the joint.

Mould shoe should match with dry moulds.

Rail ends are to be pre-heated uniformly

Crucible should be charged with magnesite powder at regularintervals of 8-10 weld joints.

The crucible should be free of moisture and charging should bedone periodically.

Th h i h b h ibl d d ld h ld b


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72 UTS portions should not be utilized for 90 UTS rails.

Rail ends should not be welded without cleaning with K.oil and

wire brush.

No bolt hole should be within 40mm from the rail end.

Worn out and damaged tools, equipment should not be used forwelding.

Location where portions are stocked should not be damp/wet.

Weld portions and luting sand should not be utilized after expirydate.

Damaged dry moulds should not be used for welding.

Damaged and loose portions should not be utilized.

Portions should not be tampered with.

Luting sand should not be mixed with ordinary local sand in caseof shortage.

Wedges under the rail should not be removed for a minimum of 20minutes after chipping.

Portions should not be utilized without proper mixing prior towelding.

Rail tensor should not be used for distressing before weld coolsdown.

The first train should not be allowed over the welds before 30

minutes after the molten steel poured in to mould

Speed restriction should not be relaxed till grinding of weld is

completed.


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Circulars and

Correction Slips onAT Welding

MANUAL FOR FUSION WELDING OF RAILS BY ALUMINO


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MANUAL FOR FUSION WELDING OF RAILS BY ALUMINO

THERMIC PROCESS

REPRINTED-2006

ADDENDUM & CORRIGENDUM SLIP NO.06 OF AUGUST, 2007

1. Following shall be added at the end of Para 4.1

Significant advancements have taken place in pre-heating techniques, type of moulds,type of crucible and process automation in the field of AT Welding. These advancements

offer significant benefits in terms of service life of AT welds. In order to absorb these

technological advancements, use of compressed air-petrol or better pre haring, single shotcrucible, automatic tapping of molten metal and three piece moulds shall be increasinglyused for rails of 52Kg and higher sectional weight with 90UTS and higher grades. Air-

petrol pre heating with manual pressurization and/or manual tapping of molten metaland/or use of two piece moulds shall be phased out for such rails.

2. Para 4.10.4 shall be modified as under:

After pre-heating the rail joint , the sparkler shall be ignited and inserted in the

portion at the centre top to start the reaction. The reaction shall not be vigorous orboiling. By the time the reaction is complete, the burner shall be removed quickly and the

gap closed with a dried sand core in case of central pouring to prevent loss of heat andturbulence during flow of metal. In case of manual tapping, the time period between

removal of burner and tapping of metal should be as minimum as possible. After the re-action subsides, about three seconds shall be allowed for the separation of slag from the

metal, which may be judged by looking into the crucible through coloured glass toIS:5983 when manual tapping of molten metal is employed.. Thereafter, the molten steel

shall be tapped into the mould by striking the closing pin with a tapping rod. It shall beensured that since the commencement of the reaction, thermit steel is tapped within the

time limit specified. Incase of automatic tapping of molten metal, these aspects are takencare of automatically. Care shall b taken to ensure that the crucible does not move from

its position during tapping. When pouring is over, the crucible and swivel stand shall beremoved and kept aside without disturbing the joint. If the reaction is found to be boiling,

the metal shall be out-tapped. Vigorous reaction and loose closing of crucible may causeself tapping. In this case also, the metal shall be out tapped. If, in any case, self tapped

metal enters the mould, the joint shall be rejected, cut and re-welded. In cases of outtapping, the joint should be cooled to ambient temperature and the process of welding

restarted afresh. However, if temperature can be measured, the rail ends may be heated to

Departmental welders certified by TPP/Thermit welding Centre (TWC)


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Departmental welders certified by TPP/Thermit welding Centre (TWC),Vijayawda with TPP portions,

Para 4.1.1.1(d)

Departmental welders certified by TPP/Thermit Welding Centre(TWC),Vijayawada with portions, consumables and preferably equipments also suppliedby an RDSO approved portion manufacturer. This is applicable for 25mm gap

welding only.

4. Para 4.1.2.3 shall be modified as under:

4.1.2.3 Training and certification of Departmental welders and supervisors

shall be done by Thermit Portion Plant (TPP), Northern Railway,Lucknow and Thermit Welding Centre (TWC), South Central Railway,Vijayawada as per procedure for certification given in Annexure-1.

5. Following shall be added as the end of para 4.8.3:

In case of three piece moulds, care should taken to ensure proper fixing of bottom

plate to avoid formation of fin at the edges of bottom flanges of weld.

6. Para 9(xii) shall be modified as under:

The tapping shall be done within the time specified for that particular technique orautomatically. For special type of welding i.e. 75mm gap, combination joint etc., the time

of reaction and tapping shall be as stipulated by RDSO for that particular weldingtechnique.

7. Following note shall be added at the end of Annexure-I:

Note: Thermit welding centre (TWC), South Central Railway, Vijayawada is also

authorized for training and certification of departmental welders and supervisorsfollowing the complete procedure indicated in Annexure-I for TPP.

8. Last line of para 4.2.3.1 of Annexure-8 of the Manual shall be reworded as follows:

The test weld shall withstand minimum transverse breaking load as indicated in

column 4 of Table-2. The deflection at centre at the actual transverse breaking load shallnot be less than that specified in column 5 of Table-2.

Welding shall be supervised by trained welding supervisor and carried out by carried


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Welding shall be supervised by trained welding supervisor and carried out by carriedwelder having valid competency certificate from RDSO/TPP, NR, Lucknow/TWC,

Vijayawda in their possession.

MANUAL FOR FUSION WELDING OF RAILS BY ALUMIO-THERMIC

PROCESS-1988(REFRINTD,2006)

ADDENDUM & CORRIGENDUM SLIP NO.07 OF NOVEMBER, 2007

1. Following shall be added as New Para No.4.2.3

4.2.3 Storage and transportation of Portions.

General guidelines for storage and transportation of AT Portion, representing best

practices with respect to storage of materials, are contained in Annexure-11.

2. Enclosed Annexure-11 shall be added after existing Annexure-10.

General guidelines for storage and transportation of AT portion

These guidelines represent Best Practices with respect to storage of materials.

Stores should be dry, well ventilated and where required lightening, power and runningwater should be available. In all cases building construction should be in compliance with

the FIRE regulations applicable to the substances being stores. Consideration shall alsobe given to the relevant regulations issued in this respect.

The appropriate notices should be displayed where materials such as thermit portions andigniters are stored.

Storage of Thermit portions

Portions should be stored in a secure, non-combustible building, While it is preferablethat they should be stored separately, they may be stored with other non inflammable

materials, such as equipment and small tools, mould, luting sand in sealed bags etc., inwhich case ideally they should be segregated. The store should be dry with ventilation to

The sealed boxes must not be opened until immediately prior to use Any spillages


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The sealed boxes ,must not be opened until immediately prior to use. Any spillagesshould be immediately swept up and the material disposed in accordance with safety data

sheets. Steel shovels should not be used on concrete floors, which might create a spark.

Portions should be used in rotation i.e. first in-first out.

Proper notices should be displayed inside and outside the building together with the

standard warning sign, which should read Metallic Powder: In case of fire DO NOTUSE WATER.

The Local Fire Brigade should be informed of exact location of store and nature ofcontents. Only dry powder extinguishers of appropriate class should be used in the

proximity of Thermit powders.Storage of igniters,

Tubes of igniters should be stored in a locked steel cupboard or other secure steel

container no account must these be stored in the same building as the portions.

Transportation of AT Portion.

AT Portion should not be transported in passenger coaches. The package containing

igniter should be kept in tin cases/steel containers.

Manufacturer of portion shall provide a sheet containing best safety practices with everypackage for guidance of the user covering various aspects in safe handling, storage,

transportation and disposal of thermit material.

MANUAL FOR FUSION WELDING OF RAILS BY ALUMINO-THERMIC

PROCSS-1988

(REPRINTED, 2006)

ADDENDUM & CORRIGENDUM SLIP NO.08 OF SEPTEMBER, 2008

1. Para 5.6 is revised as under:

5.6 TRACEABILITY OF WELDS:

5.6.1 MARKING : Each joint shall have a distinctive mark indicating month, year ofwelding, agency and welder/supervisor identification code number (as appearingon his competency certificate) at non-gauge face side of AT weld on head as


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Figure: Location of marking non-gauge face of welds

Month Last two digits of year

A A B B B C C C

Identification code

Where,

A A

code number for the agency to which the welder/supervisor belongs i.e.00 for AT portion manufacturing firms

01 for departmental welders02-99 for welders of welding contractor. The codes shall be allotted for different

Contractual agencies undertaking AT welding of rails (other than portion manufacturers)

B B B

- Specific person number (from 001 to 999). The specific person number will be

continuous for a Zonal Railway.

In case of welders belonging to the welding contractor, this code will signify the

portion manufacturing firm for which the competency certificate of welder is valid.

For example 01001 Eco would indicate a departmental welder/supervisor of East Coast

M M Y Y

The Organization issuing competency certificates shall ensure that there is no duplication


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g g p y pof the Identification Code Number.

An annual list of valid competency certificates will be circulated by the organizationissuing the competency certificates to the zonal railways. Zonal Railways shouldconstantly update and maintain the list of supervisors and welders along with their

identification code number. Annual list of approved AT welders of different firms andvalidity of competency certificates may be seen on web site www.rdso.gov.in under

button activity of Metallurgical & Chemical Due.

20 MARKING

Each joint shall have a distinctive mark indicating month, year of welding, agencyand welder/supervisor identification code number (as appearing on his competency

certificate) at non-gauge face side of AT weld on head as given below :

Figure: Location of marking on non-gauge face of welds

Month Last two digits of year

A A B B B C C C

Identification code

Where,

A A

Code number for the agency to which the welder/supervisor belongs i.e.00 for AT portion manufacturing firms

01 for departmental welders

M M Y Y

C - For welders/Supervisors of Zonal Railways: First two/three initials of the Railway


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p y yto which the supervisor or welder belongs

or

For welders/Supervisors of portion manufacturing firms and weldingcontractors: Code allotted for the portion manufacturing firms, for whom

welders/supervisors of portion manufacturing firms and welding contractors areapproved.

Alphabetic code allotted to the portion manufacturing firms are given below:

ITC = T, HT1=H, OTPL=O,ST1=S, RMPL=R, IFA=F, TPP(NR)=N

In case of welder belonging to the welding contractors, this code will signify the

portion manufacturing firm for which the competency certificate of welder is valid.

The marking should be embossed on the non gauge face side of AT weld bypunching after finishing of the weld in letters/digits of 6mm height located as indicated in

Figure.

In addition to this, alphabetic code allotted to portion manufacturing firm as per a)above e.g. T,H,N etc., and year of manufacture (last two digits of the year) shall also be

embossed on the mould to appear on web collar.

For example, 01001Eco would indicate a departmental welder/supervisor of East CoatRailway with specific person number 001. Similarly, 00001T would indicate a welders/

Supervisors with specific person No.001 of portion manufacturer whose code is T i.e.,ITC 02001H would indicate a welder, belonging to welding contractor whose code is 02,

having specific person number of 001 and having competency for welding withportion/technique of portion manufacturing firm with code H.

CFor welders/Supervisors of Zonal Railways: First two/three initials of the Railway to

which the supervisor or welder belongs.Or

For welders/supervisors of portion manufacturing firms and welding contractors:

Code allotted for the portion manufacturing firms, for whom welders/supervisors ofportion manufacturing firms and welding contractors are approved.

The marking should be embossed on the non gauge face side of AT weld by


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punching after finishing of the weld in letters/digits of 6mm height located as indicated in

Figure.

In addition to this alphabetic code allotted to portion manufacturing firm as per a)above e.g. T.H, N etc., and year of manufacture (last two digits of the year) shall also be

embossed on the mould to appear on web collar.

For example, 01001Eco would indicate a departmental welder/supervisor of East CoatRailway with specific person number 001. Similarly, 00001T would indicate a welder /

Supervisors with specific person No.001 of portion manufacturer whose code is T i.e.,

ITC 02001H would indicate a welder, belonging to welding contractor whose code is 02,having specific person number of 001 and having competency for welding withportion/technique of portion manufacturing firm with code H.

5.6.2 WELD RECORDS:

PWI shall maintain Thermit Weld Register as per proforma given in Annexure 5. Thewelded joints shall be serially numbered in a kilometer. Repair welds/additional weldsdone at a later date may be given continuing weld number in that kilometer/ For example,

the last thermit weld number in a particular kilometer was 88 and subsequently a thermitweld has been executed, it shall be numbered 89, irrespective of its location in that

kilometer.

2. Two new columns, Column No.18 Chainage of weld and Column No.19Reference point for chainage, are added in Proforma for Thermit Weld

Register, at Annexure 5.

MANUAL FOR FUSION WELDING OF RAILS BY ALUMINO-THERMICPROCESS-1998

(REPRINTED, 2006)

ADDENDUM & CORRIGENDUM SLIP NO.09 OF FEBRUARY, 2009

1. Following is added at the end of para 3.1:Further, fish bolt holes must be eliminated as far as possible before welding of rails to

Copy of Headquarters letter No.W.T-5/P/Vol.XIII, Date: 20-8-2009


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JOINT ENGINEERING AND OPERATING CIRCULAR

Sub: Traffic Block for removal of cautions due to Rail / Weld failures and cutting of rails.

***Instructions have already been issued by Engineering Department regarding carryout

repair of rail fractures and weld failures including the cutting of rails under Traffic Blockonly. To minimize the traffic block requirements, it has also been instructed to replace

hacksaw blades by Abrasive Disc Cutters on priority and with due urgency.

With a view to streamline the procedure for removal of cautions due to rail / weldfailures, the following further instructions are issued regarding the management of traffic

blocks for immediate compliance.

1. The work of repair of rail fractures and weld failures including the cutting of railsshall be carried out under traffic block only. No deviations are permitted under

any circumstances.

2. The removal of caution due to rail /weld failures will normally require two cuts antwo welds after inserting the rail of suitable length (not less than 4 meters).

3. The traffic block requirement involving two cuts and two welds shall be 100minutes where the rail cutting is done by Abrasive Disc Cutters. In case the railcutting is done by hacksaw blades, the block requirement shall be 120 minutes.

4. When situation warrants due to more cautions on account of rail / weld failures,Abrasive Disc Cutters, from SEs/P.Way of adjacent sections shall be pooled up

and deployed, to complete the work early.5. Wherever Abrasive Disc Cutters have been deployed, traffic block of 100 minutes

only shall be demanded and granted for repair of fractures involving 2 cuts and 2welds. Divisions shall make efforts to procure and deploy abrasive rail cutters in

all sections.6. On other sections, where rail cutting is to be done by Hacksaw Blade, traffic

block of 120 minutes shall be demanded and granted for repair of fracturesinvolving 2 cuts and 2 welds.

7. In case of non-availability of continuous block of 120 minutes duration, the samemay split in two parts i.e., a block of 30 minutes followed by another bock of 90minutes duration. In case of split block f (30+90) minutes, due regard shall begiven to the prevailing temperature at the time of second block, so that the gaps

available at the time of welding during the second block are close to 25 mm. A


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Copy of Headquarters lr No W T 5/P/Vol XIII dated 20 8 2009 addressed to All


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Copy of Headquarters lr. No.W.T-5/P/Vol.XIII, dated 20.8.2009 addressed to All

Sr.DEN/Co-ordinations of S.C.Railway

Sub: Repairs to rail / weld failures and cutting of rails on running lines.

***Instructions exist vide para -15.08, Chapter XV of G&SR-2008 and also Rly. Board lr.

No.98/CE-II/INSPN.5 dt.7/15.8.98 that track works leading to discontinuity in track suchas causal renewal of rails, temporary / permanent repairs of rail /weld failures shall be

undertaken under traffic block only. It has come to notice that the work of rail cutting

prior to rail renewal is being undertaken in between the train gaps with banner flag andcaution order protection without ensuring traffic block, which is an unsafe practice. Attimes, such situations have resulted into derailments also. It is pointed out that the work

of cutting of rails is an integral part of rail renewal activity and is therefore required to beexecuted under clear block protection.

To avoid such unsafe situation, following instructions are issued on the subject matter for

strict compliance in the field with immediate effect.

1. Cutting of running rail on running lines should be undertaken under TrafficBlock only. No deviations are permitted under any circumstances.

2. The work of repair of rail fractures and weld failures including the cutting ofrunning rail shall be carried out under traffic block only.

3. To minimize the traffic block requirements, for works involving rail cutting,hacksaw blades are replaced by the Abrasive Disc Cutters, on priority and

with due urgency.4. Gas cutting shall not be carried out on running rails. In case it is essential to

resort to gas cutting due to emergency, the gas cut rail shall be treated as IMRrail and same will be removed within 24 hours at first opportunity. Till such

time necessary speed restriction shall be imposed duly posting a watchman.5. In case of rail cutting by Abrasive Disc Cutters, traffic block of 100 minutes

shall be demanded for repair of fractures involving 2 cuts and 2 welds.6. In case of rail cutting by Hacksaw Blades, traffic block of 120 minutes shall

be demanded for repair of fractures involving 2 cuts and 2 welds.7. In case of non-availability of continuous block of 120 minutes duration, thesame may be split in two parts, a block of 30 minutes for cutting followed byanother block of 90 minutes duration for welding.

8. Block requirement for works involving one cut and one weld shall be suitably

South Central RailwayEngineering Standing Order No 59


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Engineering Standing Order No.59

.

Sub: Anti-corrosive treatment of Rails, Welds and other P.Way fittings Reg.***

1. The problem of corrosion and formation of pits at liner contact area on rails exists insome of the sections of this Railway. Identification of such sections was done andcirculated to Divisions for taking various preventive measures. The matter of

corrosion and its damaging effects had come up for serious discussions during theSr.DENs meeting held on 13.12.07. During the above meeting it was brought out

that heavy corrosion is also developing in some of the areas which are not identified

earlier. Taking above situation into account, the position has been reviewed and thelist of corrosion prone sections, division wise is revised as under:

S.No. Division Location

1. Vijayawada All routes of Vijayawada Division

2. Guntur KCC-GNT, GNT-TEL-RAL, GNT-

NLPD-NDKD-MRGA, GNT-NRT,NDKD-MCLA

3. Secunderabd MDR-KI (UP& DN), PGDP-SC-HYB-LPI (UP&DN)

4. Guntakal GDR-KHT-RU (UP & DN), RU-TPTY (UP&DN_

5. Nanded Nil

6. All Passenger Platform lines at

stations of all divisions

--

8. All Tunnels of all Divisions9. All cuttings in approaches of

Major towns of all Divisions.

2. It was further noted that the instructions on various measures to prevent corrosion arenot available in one single circular. Thus, a need to issue all related instructions in a

consolidated circular was felt. Therefore, various measures to control corrosion onrails and fitting have been summarized as under:

2.1Anti-corrosive treatment of rails, welds and other P.Way Fittings(A)Frequency of lubrication of ERCs and sealing for liner contact area shall be as

under:

i. On corrosion prone areas ERC greasing (all 4 ERCs) and sealing of liner

a) Painting of new rails: All new rails shall be painted before laying, with oneprime coat of red lead and two coats of red oxide as per instructions circulated


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prime coat of red lead and two coats of red oxide as per instructions circulated

vide letter No.W.501/1/7/Vol.VII, dated 8.4.04

b) Painting of in-service rails: Painting of in-service rails shall be carried outdepending upon condition, but not earlier than once in two years on innergauge face (web and flange) using two coats for anti-corrosive Bituminous

black paint as per instructions circulated vide lr. No.W.501/1/7/Vol.VII,dt.8.4.2004. Sealing of liner contact area should be done after scrapping and

painting. The activities should be planned accordingly.

(C) Weld collar painting: On identified corrosion prone areas, weld collars shall be

painted once a year, with two coats of anti-corrosive bituminous black paintconforming to IS 9862-1981, to a thickness of 200 Microns and on non-corrosiveprone areas, once in two years.

(D)Use of galvanized metal liners, galvanized plate screws and stretcher bars inpoints and crossing areas.

a) Galvanized liners In all identified corrosion prone areas.

b) Galvanized Plate screws and Stretcher bars - In all areas irrespective ofcorrosion Proneness.

(E) Frequency of lubrication of plate screws in points and crossings-

i) In corrosion prone areas - Once in a yearii) In other areas - Once in two years

This issued with the approval of PCE.

Sd/- (S.P.SAHU)Chief Track Engineer

Forwarded vide lr. No.501/I/7/Vol.VIII Dt.02.1.08


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Copy of Headquarters letter No.509/P/AT Welders & Welding, dated 29.10.2008


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py q g,

addressed to All Sr.DEN/Co-ordinations of S.C.Railway.

Sub: Standard Register for recording rail / weld fractures reg.

Ref: CTEs Inspection Notes No.35/2008 vide letter No.W.246/CTE/04/Vol.III,dt.20.10.08.

***

A standard printed register for recording rail / weld fractures (for use of

SSE/SE/P.Way of open line) containing 15 columns for recording various details wasissued to Division earlier.

CTE vide Para-7 of the above referred Inspection Notes has observed that theRegister do not have columns for noting down the name of agency, name of welder etc.,

which are required to monitor performance of the same. It was advised to re-design theproforma of the register incorporating these details. Divisions are advised to furnish the

desired revised format and the number of copies required for each division, to arrange

from Hqrs.

In the meanwhile, the details of welding agency and the name of welder may

please be recorded in the Column No.11 (type of welder) and Column No.12 (date ofwelding) along with the details for the printed item in the next line.

Please acknowledge the receipt of this letter, with the details asked above.

Sd/- (J.N.GUPTA)Dy.CE/Tr.II

Copy of lr.No.B/W.413/GL/Joggled Fish Plates/P.Way-II, dated 14.11.07 addressed


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py gg y

to All ADENs & SSEs/SEs/P.Way on BZA Division.

Sub: Precautions to be taken on Passenger intensive routes Joggling of ATWelds Reg.

Ref: 1) CTE/SCs letter Nos. W.413/Joggling, dt.21.6.07, 10.8.07 and 13.9.7

2) This office letters of even No., dated 8.7.07 and20.9.07.***

Please refer to the letters cited under reference wherein it was advised thatjoggling of AT welds has to be done at the following locations as per the extentinstructions and the same should be completed before 31.10.2007 without fail.

1) All AT welds in locations where the track has carried more than 50% of thestipulated GMT.

2) All AT welds in well fracture prone locations.

3) All AT welds on the outer rails of curves with curvature 0 and above.

4) All AT welds on major and important bridges and their approaches on either sideupto 100 Mtrs.

5) All AT welds on Track where the height of the bank is 4 M and above.

Please ensure Joggled fish plating of all the AT welds in the above locations ofyour section is completed before 24.11.07 without fail and the compliance report shouldbe submitted to this office to advise Hqrs. Office by 26.11.07.

This has the approval of Sr.DEN/Co-ord/BZA.

Sd/-For Sr.DEN/Co-ord/BZA

Copy to: All DENs of BZA Division.


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C


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Copy of Headquarters letter No.W.509/P/W-6/Vol.XI, dt.27.12.07 addressed to All

Sr.DEN/Co-ordinations of S.C.Railway.

Sub: Storage of welding portions and other materials related to rail welding.

Ref: Correction slip No.7, dt.7.12.07 to Allumino Thiermit (AT) Welding Manual

circulated vide Hqrs. lr. No.W.509/W-6/Vol.XI, dt.26.12.07.***

The above mentioned Correction Slip stipulates detailed instructions on careful

storage and handing of AT welding portions.

During inspections, it is noted that the present practice of storage and handling of

welding portions and related materials requires improvement and there is a need totighten up the machinery.

As per the C.S., there has to be a separately earmarked room for storing of

welding portions with proper system of storing and handling.

Sr.DEN/Co-ord are requested to plan for developing such specially earmarkedroom at each PWI HQ to ensure that welding portions are stored / handled as per the

instructions contained in the above mentioned Correction Slip. This will be another stepin the direction of improvement of welding quality.

An action plan for developing the facility should be submitted to the undersigned

by 15.1.2008.

Please acknowledge receipt.

Sd/- (S.P.SAHU)

Chief Track Engineer

Copy of Headquarters letter No.W.32/1/NG/PWIS/Thermit Welding, dt.18.5.07

addressed to All Sr.DEN/Co-ordinations of S.C.Railway.


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Sub: Competency Certificates of Welders.***

Cases have come to notice that Competency Certificate of agencies Welderscarrying out the welding are not found to be available with the Railways for immediate

verification. In some of the cases, long time has been taken to produce competencycertificate when called for verification.

Henceforth, it shall be ensured that Welders Competency Certificates (Original)shall be kept in the custody of sectional ADEN till such time Welder is working in hissession. Welder shall carry attested Xerox copy of Competency Certificate for

verification by inspecting Officers.

List indicating name of welder and Identification Code should be available inDivisional Engineering control for cross-check and verification. A list of agencies

welders working in the division along with competency certificate number and

identification code should be sent to Hqrs. for record by 25.5.2007.


Copy of Headquarters letter No.W.496/TWR/W-6, dt.11.4.07 addressed to All

Sr DEN/Co ordinations of S C Railway


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Sub: Precautions of Consumables / Accessories required for DepartmentalWelding

***

It has come to notice that some of the consumables / accessories required fordepartmental welding are not available in sufficient quantities affecting quality of

welding work. The value of these items is very negligible as compared to the overall cost

of welding. However, considering the quality aspects, it is essential that these items areprocured locally whenever required preferably through the petrol imprest available withAENs for welding work. This will avoid creating of inventory and wastage due to long

storage period. The amount of imprest may be got enhanced considering the monthlyrequirement and the imprest may be designated as Petrol-cum-Consumable Imprest

for Welding. A copy of the statement obtained from BZA Division is enclosed forready reference. This statement indicates consumables / accessories, which are generally

found inadequate.

It is advised to take necessary action to suitably enhance the amount of imprest and issueinstructions to AENs for arranging procurement of consumables / accessories from the

approved RDSO suppliers as and when required.


Copy of Railway Boards letter No.Track/21/2004/0902/7, dated 08.02.08 addressed

to PCEs of All Indian Railways.


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Sub: USFD testing of AT welds using digital AT weld testers.***

Digital Ultrasonic equipment for Aluminothermic Weld was developed by RDSOin association with trade for quite some time. These Ultrasonic Weld Testers are not only

handy but also can record data being a digital equipment. Moreover, PWI/USFD canhimself do the probing operation and view the signals on the monitor simultaneously.

Therefore, the quality of testing improves drastically with its use.

As on date, there are two RDSO approved vendors for the equipment, namelyM/s.Modsonics Instrument Manufacturing Company Pvt., Ltd., Ahemdabad and M/s.

Parikh Industries, Mumbai.

Railway Board has now decided that al ultrasonic testing of AT welds henceforthwould be carried out using RDSO approved digital ultrasonic equipment. Six months

time period has been fixed for the procurement of equipment / development of requisite

infrastructure. Therefore, Railways are advised to take necessary action in this regard andcompliance report be sent to Board.

Sd/- (S.K.AGRAWAL)

Executive Director Track (P)Railway Board.

Copy of Headquarters letter No.W.507/Genl/USFD/Vol.XX/2, dated 04.03.2008

addressed to Sr.DEN/Co-ordinations of S.C. Railway.


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Sub: USFD testing of AT welds using digital AT weld testers.Ref: Rly. Board lr. No.Track/21/2004/0902/7, dt.8.2.08.

***

Railway Board vide letter under reference, advised that all ultrasonic testing ofAT welds henceforth would be carried out using RDSO approved Digital Ultrasonic

equipment. Six months time period has been fixed for the procurement of equipment /

development of requisite infrastructure.

In view of the above, divisions are advised to make necessary arrangements for

procurement of the above mentioned machine based on the requirement. The necessaryRDSO specification, along with Budgetary offer received from he M/s.Electronic &

Engineering Co.(I) P. Ltd., is enclosed herewith for immediate process.

Sr.DEN/Co-ord are personally responsible for submission of the vetted indent as

per the requirement, to this office by 20.3.2008.

This is as per instruction of CTE please.

Encl: As above

Sd/- (B.VENKATA RAO)XEN/TRACK-1

For Chief Track Engineer.

Copy of Headquarters letter No.W.509/P/Vol.XI, dt.25.07.2007 addressed to All



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Sub: Improvement in Welding Technology.

Ref: ED/Tr/RDSOs lr. No.CT/Welding/Policy, dt.21.6.07

***RDSO vide above referred letter (copy enclosed) have advised six welding firms

to gear up for improving the welding technology by:

i) Introduction of Compressed Air Pre-heating along with use of 3 piece

Moulds w.e.f01.09.2007ii) Use ofAutomatic Tapping Thimbles w.e.f. 01.12.2007

It is stated that the above deadline has been fixed by the Railway Board.

Divisions are therefore, advised to immediately follow the condition as mentionedat (i) above, i.e, use ofCompressed Air Pre-heating arrangement along with 3-piece

moulds for All AT welding tenders in which execution will come into effect from

1.9.07 onwards. These instructions should be specifically noted and implemented in theinterest of improvement of AT welding quality immediately.

Please acknowledge receipt of the letter.


Copy of Railway Boards letter No.Track/21/99/0910/7, dated 30.5.07 addressed to

PCEs of All Indian Railways.


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Sub: Precautions to be taken on Passenger intensive routes.

***Board (ME) desired that following precautions should be taken on the passenger

intensive routes (Prority-1) and on CC+8+2T routes (Priority-2):

1. Joggle fish plating of the thermit welds (irrespective of age) on the outer rail of thecurves should be done on priority. The fist plating should be done using clamps

without drilling of holes.

2. Joggle fish plating of the thermit weld on the bridges along with its approaches upto100 m should be done.

3. Each and every weld fracture is to be analyzed by sectional Sr.DEN/DEN. It shouldbe ascertained whether weld failure is sudden, due to some impact or it is due to aninherent defect leading to fatigue like, improper fusion or blow holes or presence of

fin etc., remedial action due to be identified and taken promptly.

Sd/- (S.K.AGRAWAL)

Executive Director Track (P)Railway Board.

Copy of Headquarters letter No.413/Joggling, dt._______ addressed to All



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Sub: Joggled fish plating of all thermit wells on sections with traffic densityless than 15 GMT.

***

As per Railway Board E.S.O. No.34/3/1 (Revision-1) dated 10.11.2004 para 5(1)for lines with traffic density less than 15 GMT normally TWR is to be planned on

completion of 50% stipulated fatigue life of the rail. If it is decided to continue with old

thermit welds in view of very less traffic, complete weld testing be done, once in fiveyears, irrespective whether testing is due as per GMT criteria or not. In case such testingis not done, welds more than 15 years old should be joggled fish plated with two far end

tight bolts.

In this context due to the constraint in manpower for USFD testing, it is decidedto joggle fishplate all thermit welds of age 15 years or more where traffic density is less

than 15 GMT. Hence, it is advised to plan for the joggle fish plating of all such thermit

welds on identical locations in following sections.

Division Section

Secunderabad SC-WD (DN LINE)

MTMI-JPTNVKB-PRLI

SNF-MLY (Bye Pass)

DKJ-MUGRKRA-SYI

Nanded MMR-PAUPBN-PRLI

ADB-PMPT

Hyderabad FM-DHNE

Guntur NLPD-NDKD-MRGA

Divisions are advise to identify the number of welds requiring fish plating inabove mentioned sections and plan for fish plating duly making necessary arrangements

for procuring fish plates. Till such time fish plating is not done, weld testing may becarried out as per prescribed frequency.

Copy of Headquarters letter No.W.413/Joggling, dt.21.6.07 addressed to All



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Sub: Precautions to be taken on Passenger intensive routes.

***

In regard to the above subject, a copy of the Railway Boards letterNo.Track/21/99/0910/7, dt.30.5.2007 is enclosed herewith for information, wherein it has

been instructed to take the followed precautions on the passenger intensity routes(priority-1) and on CC+8+2T routes (Priority-2).

1. Joggle fish plating of the thermit welds (irrespective of age) on the outer railof the curves should be done on priority. The fish plating should be doneusing clamps without drilling of holes.

2. Joggle fish plating of the thermit weld on the bridges along with itsapproaches upto 100 m should be done.

3. Each and every weld fracture is to be analysed by sectional Sr.DEN/DEN. Itshould be ascertained whether weld failure defect leading to fatigue like,

improper fusion or blow holes or presence of fin etc., remedial action due to

be identified and taken promptly.

In this connection it is advised to follow Boards instructions as received giving

priority to sharp curves (In order of sharpness in the division) and taking into account theimportance of routes based on passenger traffic.

The progress of the above work done should be furnished in the new PCDO

proforma every month without fail so as to enable this office to compile and put up to

Board.


ENGINEERING STANDING ORDER NO..60

Sub:-Corrosion on Rail foot due to Liner Bite - Protection reg.


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g

*****Instructions regarding protection of rail against corrosion on rail due to liner bite

have been issued from time to time. On study of the problem in detail, it is noted that averagerate of corrosion on rail foot is of the order of approx. 1 mm per year without application of

any protective measures. In order to overcome the problem, detailed consolidated instructionson anti-corrosive treatment or rails, welds and other P.Way fittings have also been issued vide

ESO No.59, indicting various protective measures to be taken on rails and other fittings.Divisions should ;meticulously adopt all the measures mentioned therein.

2. It is noted that the ate of corrosion has slowed down after taking preventive measures,like; initial painting of rails, sealing of liner contact area with grease graphite, galvanizing ofliners etc. Study of rails laid in severely affected corrosion prone areas in BZA Divn. Revealed

that even with protection measures, like initial panting of rails and sealing of liner contact areaat one year interval, there is possibility of corrosion at liner contact area setting-in after a

period of 3 to 4 years. Considering the situation as brought out above, there is likelihood ofcorrosion pit crossing a limit of 1 mm within a period of 4 to 5 years. It has also been noted

that there is very little corrosion either on rail foot or, fittings on non-gauge face side. Also, thearea in between the sleepers is comparatively free of corrosion pits.

3. In order to overcome the problem of rail failures, rising out of deep corrosion pits in linercontact area, it has been decided to carryout he operation of rail distressing involving shiftingof liner contact area irrespective of any other criteria. During this process,. It shall be ensured

that the exiting liner contact area is shifted away from the sleeper set by a minimum of 150mmby physically pulling the rail, using rollers and rail dollies / tensors, in the direction of Traffic

in case of Double line, followed by distressing of panels using rail tensor, whenever required.This operation shall be addition to the corrosion protection measures as stipulated in ESO

No.59.During this process, renewal of worn-out / crushed rubber pads, corrode ERCs andliners shall also be carried out.

4. Accordingly, the operation of shifting liner contact area and distressing, on corrosionprone areas shall be carried out a under

a. At an interval of 5 years, or, before corrosion pit depth at liner contact area reaches alimit of 1.5mm, which ever is earlier.

b. Next round of de-stressing shall again be carried out after next 5 years, or, before

efforts should be made to ensure that corrosion at liner contact area is notallowed to exceed a limit of 1.5mm t any point of time.

d Th b ti h ll b t d t i t l ti d t (i) & (ii) b


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d. The above operation shall be repeated at interval mentioned at (i) & (ii) above,till rail achieves full GMT, or, there is no possibility of further shifting of railsdue to existence of number of pits on rail foot.

e. When the stage stated at (iii) above ha reached, and if rail still has residual life,operation of rail interchanging (left to right and vice-versa) shall be tried, so thatcorrosion pits are shifted to non-gauge face side.

f. The operation of sealing of liner contact area and other corrosion protectionmeasures shall continue to be carried out as per ESO No. 59 dt.02.10.08.

g. During the process of de-stressing an shifting of liner contact area, renewal ofwornout / crushed rubber pads and corroded ERCs & Liners shall also becarried out.

h. Destressing warranted on any other account as stipulated in LWR Manual videPara No.6.4.1 shall be carried out as per the site requirement.

5. Keeping in view corrosion of rail on both gauge face and non-gauge face at platformlines of station yards para 2.1 (b)(b) of ESO No.59 stands modified as under :

In-service painting of rails: In-service painting of rails shall be carried out

depending upon condition, but not earlier than one in two years. Area to be covered

shall be web and top flange only.

For locations other than platform lines, only gauge face side shall be painted. For

platform lines of station yards, Non gauge face side will also be painted.

Such painting shall consist of two coats of anti-corrosive Bituminous black paintconforming to IS 9862-1981 to a thickness of 100 microns, as per instructions

circulated vide Lr. No.W.501/1/7/Vol.V, dt.8.4.04.

Sealing of liner contact area should b done after scrapping and painting. The activitiesshould be planned accordingly.

CORROSION MEASUREMENT ON RAIL FOOT ( AT LINER CONTACT AREA)

Div Section BetweenStations


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Div Section.. BetweenStations

Track Structure Rail. Sleeper Density Annual GMT.

Whether Corrosion prone area ( Yes/No)

Corrosion depth on gauge face in mmLeft Right

Date oftesting

Location(KM/TP)

SleeperNo.

Vertical Lateral Vertical Lateral

Remarkswith

signature1 2 3 4 5 6 7 8

6.2 The register should be cross checked by ADEN/DEN/Sr.DENs during their

inspections and necessary action to implement corrosion control measuresshould be taken.

7.0 On existing rails, where corrosion pits depth is already > 3mm, operation ofdestressing, may result into shifting of liner contact area, which is not desirable.In such stretches, efforts shall be made to intensity corrosion control activitieslike; regular cleaning,. Painting and sealing of liner contact area from sleeperseat, shall also not be carried out, as such a situation is also likely to increasepropensity of rail fractures through corrosion pits on rail foot In suspendedconditions. Such stretches shall be kept under close watch.

For all such locations, Divisions shall carry out detailed survey and submitproposals for renewals ( TRR/CTR as the case may be ) in PWP as per IRPWMpara-302 (b) (ii), duly supported with relevant records and documentation.

These instructions should be brought into practice with immediate effect.

This issues with the approval of PCE.

South Central Railway

Office of the


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Office of theDRM/Works/SC

No.CW.506.Tra ck/Grade/Genl. Date 25.5.2007

All ADENs / SC Division

Sub: Performance of SKV Welders and Grading.***

A database has been developed at the Divisional office and Headquarters. CTEhas given instructions to assess the performance of the welders an grading should be

given to each welder working in your section. As ` A,B or C. The welders whosegrade is A & B only should be utilize in the field as welders. The other welders who are

graded as C should be utilized for supporting the welder and after they gain confidence,they are supposed to be upgraded. However, no welding should be done in the field who

are not having valid compe6tency certificate and graded as B or C.

Sample proforma is enclosed to fallow and the details available are to be updateand submitted to the undersigned along with the number of weldings done by the

individual during the year 2006 till date. Their performance results in terms of defectivejoints / failed joints shall b shown and considered for awarding gradations. The guidelines

given may be follows.

Marks to be awarded:

For Technical knowledge - 35 Marks For Skill in execution. - 35 Marks For quality welding - 30 Marks

(Based on defective/failed joints)-------

Total 100 Marks-----

Grading

A > or= 90 Marks

B < 90 and > or = 75 Marks


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USFD Testing ofAT Welds

ULTRASONIC TESTING OF ALUMINO-THERMIC WELDED RAIL JOINTS

1. SCOPE: Following types of testing for Alumino Thermic welds have been


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prescribed. These are:(a) Testing of weld head/web, which gets covered during through

periodic rail testing by SRT/DRT. The frequency of testing in this

case is as per para 6.8.1.1 of USFD Manual. As per this testing

defects detected in weld heads are classified as IMRW and OBSW

aide Annexure II. The action to be taken for such defective welds isas per para 6.4

(b) Periodic testing of complete weld by hand probing of weld

head/web and bottom flange using O 2MHz, 70 2 MHz, 45 2 MHz

probe ( AT weld foot scanning for half moon shaped defect) and 70

2 MHz ( 8 x 8 mm) probes. The frequency of testing in this case is

as per 6.8.2.1 of USFD Manual. As per this testing defects detected

in welds are classified as DFW . The action to be taken for such

defective welds is as per Para 6.6 of USFD manual.

(c) Besides this, welds are also tested after their execution using O 2

MHz, 70 2 MHZ, 45 2 MHz probe( AT weld foot scanning for

clustered defect/ micro porosities in web foot region) and 45 2MHz

( Tandem probe scanning for lack of fusion). This test is termed as

Initial Acceptance Test. As per this testing, defects detected in

welds are classified as DFW . The action to be taken for such

defective welds is as per Para 8.10 of USFD manual.

2. Equipment : Any RDSO approved model of ultrasonic equipment for

Alumino-thermic welded rail joints as per RDSO specification No.

3. Probes :

( i) Normal/O , 2 MHz, 18 mm Dia, Double crystal - 1 no.

( ii ) 45, 2 MHz, 20 mm Dia. Or 20mmx 20 mm square crystal size, Single


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crystal - 3 nos

( iii ) 70, 2 MHz, 20 mm Dia. Or 20mmx 20 mm square crystal size,

Single crystal - 1 no.

( iv) 70, 2 MHz, 8 mm x 8 mm crystal size, Single crystal - 1 no

4. Cable : Co-axial cable for each probe shall be used. The length shall not

be more than 2 mtrs.

5. Couplant : Soft grease shall be used as couplant.

6. Testing procedure and Classification:

Sl.

No.

Probe Calibr

ation

Sensitivity Defect

Classification(DFW)

Type of defect

Detected

Locatio

n

1 O 2MHz

300mm

60% FSHon 3 mm hole in head

From head40% or moreht.From webor foot >20%ht

To detect Porosity,Blow holes, Slaginclusion inHead&upto midweb of weld

Head &Web

2 70 S/C2MHZ 300mm 60% FSHon 3 mm hole in head

From head40% or moreht

To detect lack ofFusion, Porosity,Blow holes, Slaginclusion, Crack inHead of AT weld

Head

3 70 S/C2MHZ

300mm

60% FSHon 3 mm hole in the

middle ofthe Flangeof AT weld

40% or moreht

To detect lack offusion, Porosity,Blow holes, Slag

inclusion in Flangeof AT weld

Foot

4 45 S/C2 MHZ

500mm

60% FSHon

20% or moreht

To detect Half-moon shaped

Foot

mm) notch atBottom ofAT weld

of weld

6 45/45 500 100% of 40% or more To detect vertical Head,


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S/C 2MHZ(TandemTechnique)

mm FSH andincrease theGain by10db

oriented defectssuch as lack offusion in rail head,web and footregion below web.

Web &footbelowweb

7. Defect Classification, marking and action taken:

Classification

Markingon bothsides ofweb

Action to be taken

DFW + +With redpaint

For NEW Welds:These DFW welds shall be cropped, re-welded andtested again.For Service welds:These DEW welds on detection, SE/USFD/shallimpose SR 30kmph or stricter immediately. Heshould communicate to Sec Se about the flawlocation who shall ensure the following:

( i ) protection of DFW weld by jog. Fps using min.2tight clamps/2 far end tight bolts one on each side,after which SR can be relaxed upto 100/75 Kmph forGoods/Pass trains.( ii ) In case protection of DFW weld has been doneusing jog.FPs with clamps, the DFW weld shall bereplaced with in 15 days.However, protection of DFW weld has a been doneusing jog.FPs with 2 far end tight bolts SR shallcontinue till weld is replaced which should not belater than 3 months.The DFW weld with SR may be continued in track if

8. Weld Testing Frequency ( SKV )

S.No Type Type of testing Testing Schedule


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ofWeld

Acceptance Test Immediately after weldingFirst Periodic Test One year

Routes HavingGMT

Frequency

> 45 2 years

> 30 < 45 3 years> 15 < 30 4 years

1 SKV

Further Testsbased on routeGMT

0 - 15 5 years

9. Note: ( i ) Due to unusual high weld failure or abnormal development insome sections, Chief Engineer may order testing of welds early, as perneed.

( ii )The USFD testing can be dispensed with in case of those welds whichare more than 15 years old and protected by joggled fish plateswith far end tight bolts.

( iii ) TWR should be planned after the welds have carried 50% of thestipulated GMT of Rails.


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Extracts from T-19Manual 1994

INDIAN RAILWAY STANDARD SPECIFICATION FOR FUSION WELDING OFRAILS BY ALUMINO THERMIC PROCESS

Serial No. IRS T-19-1994EXTRACTS


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FOREWORDThis specification is issued under the fixed serial No.T-19. This was originallyadopted in 1961 and was revised in 1965 and 1984. This third revision isnecessitated to include current technological improvements in the process. In thisrevised specification, test requirements of 90 UTS, 110 UTS and Head Hardenedrails have been incorporated, acceptable percentage of porosity, tapping time andtransverse breaking load requirements have been revised.

1. INTRODUCTION1.1 The soundness of the welds produced by alumino - thermic process depends

on the quality of (a) alumino-thermic mixture hereinafter referred to as theMIXTURE and (b) the technical control exercised during the preparation forand the execution of the welding by this process.

1.2. The quantity of the MIXTURE required for welding one rail joint shall becalled a portion.

1.3. A batch shall consist of a number of portions manufactured from similarlyand simultaneously treated raw materials.

1.4. Portions manufactured by agencies approved by RDSO and accepted bynominated inspecting authority shall only be used.

1.5. Except for welds executed for laboratory evaluation

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