Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 15965 (2012): Pre-painted Aluminium Zinc Alloy MetallicCoated Steel Strip and Sheet (Plain) [MTD 4: Wrought SteelProducts]

© BIS 2012

B U R E A U O F I N D I A N S T A N D A R D SMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

May 2012 Price Group 7

IS 15965 : 2012

Hkkjrh; ekud

iwoZ-jksxu dh xbZ ,Y;wfefu;e ftad feJ /kkrq ysfirbLikr iÙkh ,oa pknjsa ¼lknk½

Indian Standard

PRE-PAINTED ALUMINIUM ZINC ALLOY METALLICCOATED STEEL STRIP AND SHEET (PLAIN)

ICS 77.140.50

Wrought Steel Products Sectional Committee, MTD 4

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the WroughtSteel Products Sectional Committee had been approved by the Metallurgical Engineering Division Council.

Till recently, there used to be 100 percent import of pre-painted hot-dip aluminium-zinc alloy metallic coatedsteel strip and sheet. Now local production has started and number of manufacturers are developing facilities forthese products. This standard has been formulated to cover the various technical requirements.

For all the tests specified in this standard (chemical/physical/others), the method as specified in relevant ISOStandard may also be followed as an Alternate method.

Annex E and Annex F for weathering performance of the pre-painted steel sheet and strip and summary of test forproperties and expected results, respectively have been added for information.

The Committee responsible for the formulation of this standard has reviewed the provisions of followingInternational Standards referred in this standard and has decided that they are acceptable for use in conjunctionwith this standard:

International Standard Title

ISO 2808 : 2007 Paints and varnishes — Determination of film thicknessISO 4628-2 : 2003 Paints and varnishes — Part 2: Assessment of degree of blistering

The composition of the Committee responsible for the formulation of this standard is given in Annex G.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded offvalue should be the same as that of the specified value in this standard.

1

IS 15965 : 2012

Indian Standard

PRE-PAINTED ALUMINIUM ZINC ALLOY METALLICCOATED STEEL STRIP AND SHEET (PLAIN)

1 SCOPE

1.1 This standard covers the requirement of pre-paintedaluminium-zinc alloy metallic coated steel strip andsheet (plain) for application as exposed buildingproducts. The typical base metal thickness (BMT) ofsheets and coils used for this application would be from0.25 mm to 1.5 mm.

1.2 Sheets and coils are produced by continuouslycoating and baking durable synthetic resin paint, forexample, polyester, epoxy, acrylic, fluorocarbon, etc,over both surfaces of hot dip aluminium-zinc alloycoated steel strip.

1.3 This standard covers requirements for differentclasses of durability of paint coatings in accordancewith the severity of the application as building products.

2 REFERENCES

The standards listed below contain provisions, whichthrough reference in this text constitute provisions ofthis standard. At the time of publication, the editionsindicated were valid. All standards are subject torevision and parties to agreement based on this standardare encouraged to investigate the possibility of applyingthe most recent editions of the standards indicatedbelow:

IS No. Title

101 Methods of sampling and test forpaints, varnishes and relatedproducts:

(Part 4/Sec 4) : Optical tests, Section 4 Gloss1988(Part 5/Sec 1) : Mechanical tests on paint films,1988 Section 1 Hardness tests (third

revision)(Part 5/Sec 2) : Mechanical tests on paint films,1988 Section 2 Flexibility and adhesion

(third revision)(Part 6/Sec 1) : Durability tests, Section 1 Resistance1988 to humidity under conditions of

condensation (third revision)1956 (Part 4) : Glossary of terms relating to iron and

1975 steel: Part 4 Steel sheet and strip (firstrevision)

8910 : 1978 General technical deliveryrequirements for steel and steel

productsIS No. Title

9844 : 1981 Method of testing corrosionresistance of electroplated andanodized aluminium coating byneutral salt spray test

14191 : 1996 Corrosion of metals and alloys —Classification of corrosivity ofatmospheres

15961 : 2011 Hot-dip aluminium — zinc alloycoated steel strip and sheet (plain)

IS/ISO 16163 : Continuously hot-dipped coated steel2005 sheet products — Dimensional and

shape tolerances

ISO 2808 : 2007 Paints and varnishes —Determination of film thickness

ISO 4628-2 : Paints and varnishes: Part 22003 Assessment of degree of blistering

3 TERMINOLOGY

For the purpose of this standard the definitions givenin IS 1956 (Part 4) and the following shall apply.

3.1 Substrate — Hot dip aluminium-zinc alloy coatedsteel strip.

3.2 Coil Coating — A continuous process by whichpaint and other coatings are applied and oven-bakedonto moving aluminium-zinc alloy coated steel strip.The product of this process is referred to as pre-paintedAl/Zn coated steel.

3.3 Organic Coating — The organic paint film of thepre-painted steel product.

3.4 Conversion Coating — A chemical treatmentnormally applied to a metal surface prior to finalfinishing, which is designed to react with and modifythe metal to produce a surface suitable for painting.

3.5 Primer — The first complete layer of paint of acoating system applied to metallic surface. This serveas the bond between the substrate and topcoat/backer-coat and offers added corrosion prevention.

3.6 Finish-Coat — A paint on the top side of the pre-painted steel. This is also known as top-coat.

3.7 Wash-Coat — A thin paint on the bottom side ofthe pre-painted steel. This is also known as backer-coat.

2

IS 15965 : 2012

3.8 Top-Side — The side of the pre-painted sheet,which is exposed to external or internal weathering.

3.9 Bottom-Side — The side of the pre-painted sheet,which is opposite to the exposed weathering side.

3.10 Coating Characteristics

3.10.1 Chalking — The formation on a pigmentedcoating of a friable powder evolved from the film itselfat or just beneath the surface.

3.10.2 Fading — Loss in colour intensity experiencedby paint over time, generally due to the effect of ultra-violet radiation.

3.10.3 Gloss — The luster, shine or reflecting abilityof a surface.

4 SUPPLY OF MATERIAL

The general requirements relating to supply of pre-painted aluminium-zinc alloy coated steel strip andsheet (plain) shall conform to IS 8910.

5 MANUFACTURE

5.1 The substrate for pre-painted aluminium-zinc alloymetallic coated steel strip and sheet (plain) shallconform to IS 15961.

5.2 Pre-painting will be done in a continuous paintingline by applying a conversion coating, primer, back-coat and finish coat on substrate. Curing of paintcoatings shall be at a temperature suitable to producean aesthetic and durable painted surface.

6 PRODUCT DESIGNATION

6.1 The product designation shall follow the sequencebelow:

a) Number of this Indian Standard (IS);

b) Steel grade (see IS 15961);

c) Coating class (see IS 15961); andd) Class of durability of paint coating (see 8.5).

6.2 The designation of steel grade shall include a set ofcharacters as follows:

a) First and second characters: to indicate yieldstrength ‘YS’; and

b) Third, fourth and fifth characters: to representthe minimum yield strength, in MPa, namely‘250’, ‘300’, ‘350’, ‘450’ and ‘550’

Example: ‘YS550’.

6.3 The designation of coating class shall include a setof characters as follows: aluminium- zinc alloy metalliccoating shall be indicated by the prefix ‘AZ’, followedby a number representing the minimum coating mass,

in ‘grams per square metre’ (GSM) of sheets or strips(total for both surfaces determined by triple spot test/on-line X-ray fluorescence method as defined inIS 15961.

Example: ‘AZ150’

6.4 The designation of the paint durability class shallinclude a set of characters as described in 7.

Example : ‘IS 15965 : 2012/YS550/AZ150/Class 3’

7 COATINGS

7.1 The minimum recommended class of thealuminium-zinc alloy metallic coated steel strip shallbe as per Table 1.

7.2 The paint coating thickness shall be measured, inmicrons.

7.3 Standard top-coat (finish coat) coating for durabilityClass 2, 3, 4 shall be minimum 15 µ and backer-coat(wash coat) shall be 4 µ minimum.

NOTE — Other top coating thicknesses, like in durabilityClass 1 can be supplied as per mutual agreement between thecustomer and the supplier depending on the end use applicationof the pre-painted product.

7.4 Primer coating shall be minimum 4 µ for alldurability classes with the exception of Class 1 whereinthe polyester or water-based paint system with mediumor low pigment may have no primer.

7.5 The recommended durability class for atmosphericclassification of IS 14191 is specified in the Table 1.

8 TEST FOR PHYSICAL PROPERTIES OFPAINT COATING

8.1 Mandatory Testing

The following tests for physical properties andappearance are mandatory at the time of production:

a) Adhesion;

b) Pencil hardness;

c) Solvent resistance;d) Colour (see 9.2 );e) Gloss (see 9.3 ); andf) Dry film thickness.

8.2 Sampling Frequency

One sample for the tests given in 9.1, or as agreed tobetween the manufacturer and the buyer, is taken fortesting from every 25 t of sheets/coil or part thereoffrom a lot of the products of the same quality,dimensions, coating mass and colour.

3

IS 15965 : 2012

Table 1 Recommended Guide to the Selection of Pre-painted Coating Class(Clauses 7.1 and 7.5)

Sl No.

Durability Class

Atmospheric Classification (IS 14191)

55 Percent Aluminium- Zinc Alloy Metallic Coating

(see Note 2)

Typical Top Coat Paint System (see Note 1)

(1) (2) (3) (4) (5)

i) Class 4 Category C4 AZ 200 ii) Class 3

iii) Class 2 Category C3 Category C2

AZ 150 AZ 150

iv) Class 1 Category C1 AZ 70/ AZ100

Polyester/Super durable polyester/Polyvinylidene fluoride (PVDF)/Water-based-acrylic

NOTES 1 Different top paint system gives different paint durability at given exposure paint systems with exterior premium durability are for long-term colour and gloss retention requirement. Class 3 denotes products with exterior premium durability compared to Class 2. 2 See IS 15961.

8.3 Adhesion Test

8.3.1 T-bend Adhesion Test

For pre-painted sheet and strip when tested inaccordance with Annex A, the adhesion of the paintshall be sufficient to prevent its removal from the metalwhen tape is pulled. All pre-painted sheet and strip shallcomply to internal bend diameter of 5 t or less, unlessagreed otherwise between the purchaser and themanufacturer.

8.3.2 Reverse Impact Resistance Test

When a pre-painted steel product test piece is subjectedto reverse impact test in accordance with Annex B usingthe impact energy level of 10 J or 1 020 kg.mm, thereshall be no loss of adhesion of the paint coating. Onvisual inspection there should not be any cracking,powdering or peeling of the paint film.

8.4 Pencil Hardness Test

Pencil hardness is one of the attributes, which depictsdegree of cure and how easily it can be processed inthe customers’ factory. Standard pencil of knownhardness should be used for the pencil hardness test[see 4 of IS 101 (Part 5/Sec 1)]. On visual inspectionthere shall not be any scratch on the tested portion.The minimum acceptable hardness shall be HBhardness minimum.

8.5 Scratch Hardness

When measured in accordance with 3 of IS 101 (Part 5/Sec 2), the scratch resistance of the coating shall notbe less than 1.5 kg or as agreed to between the purchaserand the manufacturer.

NOTE — This test is not a part of the mandatory testingmentioned in 8.1.

8.6 Solvent Resistance Test

Methyl ethyl ketone (MEK) double rub test shall be

conducted on a test piece in accordance with Annex C.This is one of the measures for determination of ovenpaint curing process completion.

8.7 Dry Film Thickness

This refers to the paint film thickness of the finish coator top coat. When measured by method 5B of ISO 2808,the supplied dry film thickness of paint coating (Finishcoat or top coat) shall comply with the requirements ofthe 7.3 of this standard or the agreement between themanufacturer and the customer.

NOTE — In order to determine the total thickness of coatingfor optimum corrosion protection the following details shouldbe considered together:

a) Coating class of the aluminium-zinc alloy metallic coatedsteel strip (for example AZ 150, AZ 200).

b) Type and dry film thickness of the top coat and the backcoat paint.

c) Type and dry film thickness of the primer.

9 APPEARANCE

9.1 General

Pre-painted metal products shall have uniformappearance, colour and texture. It will be essentiallyfree of blemishes such as flow lines, streaks, blisters orother surface imperfections. It should be reasonablyflat and free from physical imperfections like bare spots,holes, tears, etc. Sheets and coils shall be free fromdefects detrimental to practical use with the exceptionof coils which may contain some irregular portions (likewelds, colour shading, etc). Since irregular portions inthe coil cannot be removed as in the case with cut length.

9.2 Colour

The colour batch to standard shall match the ‘colourspecified’ (agreed between the pre-painted steelmanufacturer and purchaser). When tested in a lightbooth having a daylight simulator and incandescentlight source, the visual colour match shall achieve arating of 2 or lower. The classification of degrees of

ÏÌÓ

4

IS 15965 : 2012

colour match as determined by unaided visualinspection is described in Table 2. A more accurateinstrumental measurement of colour, withspectrophotometer adopting the Hunter ColourMeasurement System, is also allowed for better batch-to-batch colour consistency.

9.3 Gloss

Gloss of pre-painted metal product shall comply withthe requirement as agreed between the manufacturerand the customer, when tested using a 60° head (glossgeometry) [see IS 101 (Part 4/Sec 4)].

Gloss level shall be agreed to between the pre-paintedsteel manufacturer and paint supplier as well.

NOTE — Specular gloss unit normally do not apply to texturedfinishes. Gloss is dependant on the paint system. However,10 to 40 percent gloss with 60° head is a typical range for astandard paint system.

10 DURABILITY TEST FOR PAINT COATING

Sheets and coils will be subjected to the accelerateddurability tests given in Table 3 and described in 10.1and 10.2.

10.1 Corrosion Resistance

When suitably prepared test specimens (scribed or un-scribed, as appropriate) are exposed to the salt spraytest specified in IS 9844 and Table 3 and assessed inaccordance with Annex D, the pre-finished product shallcomply with the requirements of Table 4.

10.2 Humidity Resistance

When suitably prepared test specimens (scribed or un-scribed, as appropriate) are tested in accordance withIS 101 (Part 6/Sec 1) and Table 3 and assessed inaccordance with Annex D, the pre-finished product shallcomply with the requirements of Table 5.

Table 2 Colour Match(Clause 9.2)

Sl No. Rating Description Explanatory Note (1) (2) (3) (4)

i) 0 Exact match Colour of test sample indistinguishable from that of reference or standard sample ii) 1 Critical match A small, just perceptible colour difference can be seen when the samples are held in contact

but it cannot be detected when separated by 5 mm iii) 2 Close match When separated by 5 mm a small colour difference can be seen, but it is undetectable when

increased to 25 mm iv) 3 Approximate match When separated by 20 mm a small colour difference can be seen, but it is undetectable when

increased to 100 mm v) 4 Crude match (Poor match) Difference is readily detectable even when separated by more than 100 mm

NOTE — A standard light booth shall be used for the above qualitative measurement. These qualitative comparison measurements shall preferably be backed by colour measurements with a standard spectrophotometer for high repeatability and reproducibility of colour.

Table 3 Test Duration for Salt Spray and Humidity Resistance(Clauses 10, 10.1 and 10.2)

Sl No.

Durability Classes for Pre-painted Products Corrosion Resistance (Salt Spray) (IS 9844) h

Humidity Resistance (IS 101 Part 6/Sec 1)

(1) (2) (3) (4)

i) Class 4 2000 1000 ii) Class 3 1000 1000 iii) Class 2 — — iv) Class 1 500 500

NOTES 1 Requirements/results mentioned in Table 4 and Table will be achieved when tested to time (hours) as per Table 3. 2 Durability tests are for manufacturer’s information only and are not necessarily mandatory at the time of production/coating.

Table 4 Requirements for Salt Spray Resistance(Clause 10.1)

Sl No. Type of Deterioration Method of Test, Ref to

Requirement

(1) (2) (3) (4) i) Undercut at scribed lines D-1 Rating of 2.0 or less with no corrosion of base metal, no red rust formation ii) Corrosion of the base metal D-2 Rating 0 iii) Blistering D-3 Not worse than rating 2(S3)1)

1) Face of panel.

5

IS 15965 : 2012

Table 5 Requirements for Humidity Resistance(Clause 10.2)

Sl No.

Type of Deterioration

Method of Test, Ref to

Requirement

(1) (2) (3) (4)

i) Undercut at scribed lines

D-1 Rating of 2.0 or less with no corrosion of base metal, no red rust formation

ii) Blistering D-3 Not worse than rating 3(S2)1)

1) Face of panel.

11 DIMENSIONS AND TOLERANCES

11.1 The dimensions shall be as per IS/ISO 16163. Thetypical base metal thickness (BMT) of sheets and coilsused for this application would be from 0.25 mm to1.5 mm.

11.2 In case of coils, the mass of the coils shall notexceed 10 mt (typical) and the internal diameter of thecoils shall be 508 or 610 mm.

11.3 Sheets and coils of sizes other than those specifiedin 11.1 and 11.2 may be supplied, if agreed betweenthe purchaser and the manufacturer.

11.4 Tolerances

11.4.1 Thickness

The tolerances on Base Metal Thickness (BMT) ofsheets and coils shall be as given in IS/ISO 16163.

11.4.2 Width

No sheet or coil shall be smaller in width than thatspecified. The positive tolerance on width shall be10 mm. In case of trimmed width it shall be + 3 mmmaximum.

11.4.3 Length

No sheet shall be smaller in length than that specified.

Tolerance on length on plus side shall be 15 mm or0.5 percent of length, whichever is greater.

12 SHAPE

12.1 Camber

Minimum camber values for coils and sheets shall beas given in IS/ISO 16163.

12.2 Deviation from Squareness (Out-of-Square)

Deviation from Squareness of flat sheets shall be givenin IS/ISO 16163.

12.3 Deviation from Flatness (Steepness)

This will be in accordance with Table 6

Table 6 Flatness Tolerance

Steepness Ratio, Percentage

Class A Class B

1.2 0.5

NOTES

1 Class A tolerance, where length between the points of contact,is less than 1 000 mm, the steepness ratio percentage will be 1.

2 The steepness ratio expressed as a percentage is calculatedby determining the maximum distance between the productsurface and the straightedge and the length between twoconsecutive points of contact (see Fig. 1), then applying thefollowing equation:

Steepness ratio = (h /l) × 100, percentagewhere

h = deviation from flatness (wave height), in mm; and

l = distance between two consecutive points of contact,

in mm.

13 MASS

13.1 The mass of the sheets or coils shall be given in‘kg’ or ‘mt’ of actual.

�

�

�

� � �

�

�

� �

�

�����������

��

��

������

FIG. 1 DEVIATION FROM FLATNESS

6

IS 15965 : 2012

13.2 The mass tolerance of ±10 percentage forindividual sheet and ±5 percentage for sheet pack/coilshall apply.

14 INSPECTION

14.1 It shall be as follows:

a) The physical properties of paint coating shallcomply with requirements of item 8. Thesetests are normally mandatory at the time ofproduction;

b) Appearance shall comply with requirementsof 9. These tests are normally mandatory atthe time of production;

c) The durability test is performance test and thetests results shall comply with therequirements of 10. The durability tests arenot necessarily mandatory at the time ofproduction;

d) Dimensions and tolerance shall comply withrequirements of 11; and

e) Shape shall comply with requirements of 12.

14.2 Re-inspection

When a part of the test results for physical propertiesfails to comply with the requirement, a re-test (two moresets of test samples shall be taken for specific testrequirements from the same lot) on the relevant itemsmay be carried out to determine whether it is acceptableor not. If any of the re-test samples fail to meet the testrequirements of this standard, the entire batch of sheetsrepresented by the sample shall be deemed as notconforming to this standard.

15 PACKING AND TRANSPORTATION

15.1 Coils should be wrapped with polylaminatedcovering. Inner wrap surface (ID) should also be coveredwith polylaminated covering. The coil should then bewrapped with either steel sheet along with the side coversor with Hessian cloth covering both sides as agreedbetween the purchaser and the manufacturer.Circumferential ring and inner rings should be fitted alongthe edges. Finally it should be strapped with steel tape.

15.2 Sheets should be first wrapped with polylaminatedcovering and then with steel sheet or with Hessian clothas agreed between the purchaser and the manufacturer.Finally it should be strapped with steel tape.

15.3 Every precaution should be taken against paintcoating damage and contact with water during transit.Mixed loading with corrosive substances such aschemicals should be avoided.

16 MARKING

16.1 The following shall be legibly and indeliblymarked on the top of each coil or package of sheets orshown on a tag attached to each coil:

a) IS No. of this standard;

b) Manufacturer’s name or trade-mark;

c) Material identification/coil number/packetnumber/batch number, etc;

d) Product dimension;

e) Number of sheets or mass;

f) Coating class;

g) Colour name of top-coat; and

h) Date of packing.

16.2 BIS Certification Marking

The material may also be marked with the StandardMark.

16.2.1 The use of the standard mark is governed by theprovisions of Bureau of Indian Standards Act, 1986and the Rules and Regulations made thereunder. Thedetails of the conditions under which the license forthe use of the Standard Mark may be granted tomanufacturers or producers may be obtained from theBureau of Indian Standards.

17 STORAGE AND HANDLING OF PRODUCTS

It is essential that pre-painted products be kept dry intransit and stored under cover clear of the ground. Ifpack or coil of the coated steel become wet it shouldbe opened, wiped dry with a clean cloth and positionedso that air circulation will complete the drying process.The use of these procedures should preventdeterioration of the coating, which otherwise can leadto reduced life expectancy or poor appearance of theproduct.

Pre-painted products should be lifted directly and notdragged over rough surfaces or over each other. Careshould also be taken to avoid dragging, cutting andforming tools over the surfaces of the pre-paintedproducts.

Stocks of pre-painted products should be used inrotation as some mechanical properties of the coatingmay change slightly during prolonged storage, forexample duration greater than six months. Thesechanges are typically small and in most fabricationprocesses are not significant. However, it is possiblethat they could cause fabrication problems duringsevere forming operations.

7

IS 15965 : 2012

A-1 This Annex describes the method for assessingpaint adhesion by the T-bend test. The method issuitable for testing pre-painted sheet and strip productsup to 1.5 mm thickness.

A-2 PRINCIPLE

Pre-painted metallic products is bent flat. Adhesion ofthe paint on the outside of the bend is assessed by theapplication of adhesive tape and its subsequent rapidremoval.

A-3 APPARATUS

The following test apparatus are required:

a) A bench vice approximately 150 mm wide oralternative bending apparatus.

b) Adhesive tape 20 mm to 25 mm wide whichis semi-transparent, pressure-sensitive, andhas an adhesion strength of 5 N to 15 N per24 mm width.

NOTE — Scotch 600 tape fit the above specification.

A-4 PREPARATION OF TEST PIECES

Test pieces shall be cut out parallel to the rolling directionof the base metal and shall be of at least 50 mm width andsufficient length (200 mm long is normally sufficient) to

ANNEX A(Clause 8.3.1)

T-BEND ADHESION TEST

suit the test requirement.

A-5 PROCEDURE

a) Clamp approximately 25 mm of one end ofthe test piece in the vice.

b) Bend the test piece through 90° with thecoating to be assesses on the convex surfaceof the bend.

c) Remove the bent test piece from the vice andbend it through to approximately 180°.

d) Reinsert the test piece in the vice and compressflat. This represents a zero T-bend or startingpoint for subsequent folding.

e) Fold once around this starting point to achieve1 t and compress (the internal diameter of thebend is 1 t). Fold twice for 2 t and compress,and so on until the specified requirement asagreed between the manufacturer and thecustomer is completed.

f) Apply adhesive tape along the entire lengthof the external bend and press down firmly.

g) Remove tape with a rapid single pull at rightangles to the bend.

h) Examine the test piece for removal of paint.

NOTE — T = nominal thickness of sheet or strip.

B-1 This Annex describes a method to assess the impactresistance of pre-painted metal products and theadhesion of a coating to the base metal. This test appliesto base metal thickness from 0.4 mm to 1.5 mm.

B-2 PRINCIPLE

The test piece is struck on the reverse side by a ball ofspecified diameter and with a specified force. Adhesionof the disturbed coating is assessed by examination afterapplication and subsequent rapid removal of adhesivetape.

B-3 APPARATUS

The following apparatus is required:

ANNEX B(Clause 8.3.2)

REVERSE IMPACT TEST

a) An impact tester fitted with a male and afemale die of 19 mm diameter, or otherdiameter if specified in the product standard.

NOTE — Gardner impact tester may be used for this test.

b) Adhesive tape 20 mm to 25 mm wide, whichis semi-transparent, pressure-sensitive, andhas adhesion strength of 5 N to 15 N per24 mm width.

NOTE — Scotch 600 tape fit the above specification.

B-4 PREPARATION OF TEST PIECE

The test piece shall be cut 50 mm wide and 50 mmlong approximately.

8

IS 15965 : 2012

B-5 PROCEDURE

Reverse impact resistance shall be determined usingthe following procedure:

a) Load the test piece into the test machine withthe coated side to be tested facing away fromthe impactor.

b) Set the impactor to apply the specified impactforce.

C-1 This procedure is to be used to determine the degreeof cure of a baked film by the paint films resistance to aspecified solvent. This procedure is applicable wheneverthe resistance to methyl ethyl ketone (MEK) or methyliso-butyl ketone (MIBK) has to be determined.

C-2 PRINCIPLE

The determination of solvent resistance is carried outby using a double rub machine. This machine rubs thetest piece/panel with cotton doused in MEK or MIBK.

C-3 APPARATUS

a) Fume cupboard;

b) Protective gloves;

c) Cotton pad (~50 mm square);d) Solvent (MEK or MIBK); and

e) Solvent double rub machine.

C-4 PREPARATION OF TEST PIECE

A panel of size 120 mm × 300 mm is prepared fromthe production test sample to be tested face up in thesolvent rub machine.

C-5 PROCEDURE

C-5.1 Clamp the 120 mm × 300 mm panel in the solventrub machine.

c) Trigger the machine and impact the test piece.d) Remove the impacted test piece from the

machine and apply adhesive tape to thedeformed area of the coated test side. Pressthe tape down firmly to remove air bubbles.

e) Remove the tape immediately with rapid pullat right angles to the un-deformed surface.

f) Examine the test piece and the tape forremoval of paint.

ANNEX C(Clause 8.6)

SOLVENT RESISTANCE TEST

C-5.2 Place a 50 mm2 cotton pad between themagnetic holders on the bottom of the solvent rubmachine head.

C-5.3 Fill the reservoir with recommended solvent-MEK for top coats and bottom coats or MIBK forprimer evaluations.

C-5.4 Start the machine and stop it based onobservations mentioned in 6.

C-6 EVALUATIONS

C-6.1 Observe the operation of the solvent rub machineand stop the machine when failure has occurred. Failureshall consist of removal of the film to expose the primeror substrate at any spot along the centre-line of thedouble-rub stroke. The first and the last 25 mm of thestroke shall not be considered.

C-6.2 The solvent resistance of the organic coating isclassified as the number of strokes the machine hasmade prior to failure of the organic coating.

C-6.3 The number of rubs required is dependent onthe paint system. However completion of 50 doublerubs is sufficient for the test of standard paint system(for durability class 2, 3 and 4). Failure of the paintfilm at less than 50 double rubs is an indication of a‘problem’.

9

IS 15965 : 2012

D-1 UNDERCUT AT SCRIBED LINES

D-1.1 This method describes the assessment of thedegree of deterioration for a metal substrate that hasbeen coated by a paint system.

D-1.2 Principle

Coated test panels are exposed to an acceleratedcorrosive (Salt Spray Test) or humid (Humidity Test)environment. The corrosion on the surface of the paintfilm and on the metal surface beneath the paint film isassessed by comparison with photographic referencestandards and rating table.

D-1.3 Procedure

a) Remove loose corrosion products and anycoating that has lost adhesion from the vicinityof the scribed line by scraping with a metalspatula or dull knife.

b) Rate the mean creepage of undercut corrosionor loss of paint extending from the scribed line,as prescribed in Table 7.

Table 7 Rating for Failure at Scribe and PanelEdge

Rating Scale Representative Mean Creepage of Under Film Corrosion from Scribed Line

mm (1) (2)

0 1 2 3 4 5

> 0 > 0 ≤ 1.0 > 1.0 ≤ 3.0 > 3.0 ≤ 7.0 > 7.0 ≤ 13.0 > 13

D-2 CORROSION OF THE BASE METAL

D-2.1 This method describes the assessment of thedegree of deterioration for a metal substrate that hasbeen coated by a paint system.

D-2.2 Principle

Coated test panels are exposed to an acceleratedcorrosive environment. The corrosion on the metal

ANNEX D(Clauses 10.1 and 10.2 and Table 4 and Table 5)

METHODS OF ASSESSMENT OF SALT SPRAY AND HUMIDITY TEST RESULT

surface beneath the paint film is assessed by comparisonwith photographic reference standards.

D-2.3 Procedure

a) Carefully remove a portion or whole of thepaint film using a suitable solvent-based paintremover.

b) Determine the severity of corrosion byreferring to the pictorial standards in thefollowing Fig. 2.

D-3 BLISTERING

D-3.1 This Annex sets out a method for determiningthe degree of blistering in a paint film exposed toaccelerated weathering conditions.

D-3.2 Principle

The test is visually evaluated for the degree of blisteringby comparing with diagram reference standards, whichshows rated stages of blistering.

NOTE — The diagram reference standards have been adoptedfrom ISO 4628-2.

D-3.3 Apparatus

Diagram standards (see Fig. 3, 4 and 5) — required forcomparison with the test film.

D-3.4 Viewing Environment

Examination of the films should be carried out underlighting conditions of at least 500 lux or lumen/m2.

D-3.5 Procedure

a) Visually examine the test film by comparingthe surface finish with the reference diagramstandards (see D-3.2) that shows a similaramount of blistering.

b) Using Table 8 determine the rating for densityof blistering and Table 9 for the size ofblistering.

c) Record the rating as for example 2 (S 3)where 2 stands for density and S 3 stands forsize of blister.

10

IS 15965 : 2012

FIG. 2 TYPICAL CORROSION ON THE STRIPPED METAL SUBSTRATE

Table 8 Rating for Density of Blistering(Clause D-3.5)

Rating Scale1) Density of Blistering

0 1 2 3 4 5

None Less than few Few Medium Medium-dense Dense

1) The rating scale conforms to current ISO practice.

Table 9 Rating for Size of Blisters(Clause D-3.5)

Rating Scale1) Size of Blistering

1 2 3 4

Finer than in Fig. 3 See Fig. 3 See Fig. 4 See Fig. 5

1) The rating scale conforms to current ISO practice.

11

IS 15965 : 2012

FIG. 3 BLISTERS OF SIZE 2

12

IS 15965 : 2012

FIG. 4 BLISTERS OF SIZE 3

13

IS 15965 : 2012

FIG. 5 BLISTERS OF SIZE 4

14

IS 15965 : 2012

E-1 GENERAL

All organic coatings gradually change their appearancewhen exposed to the weather. The changes that takeplace occur at different rates depending on theaggressiveness of the environment and on the abilityof the coatings to resist those changes.

Changes in the appearance of an organic coating donot necessarily imply that the coating has lost the abilityto protect the base metal.

The changes that can occur and their likely effect onthe performance of pre-painted metal products areoutlined in E-2 to E-6.

E-2 LOSS OF GLOSS

Ageing on exposure to ultraviolet light causes initialloss of gloss. Contamination by atmospheric pollutants,for example, sulfurous and ammoniacal fumes and bythe collection of dirt can also cause deterioration ofgloss.

The rate of impairment of gloss by the collection ofdirt is less for vertically installed surfaces than forhorizontal surfaces. Pre-painted products can beexpected to retain their gloss better than products withconventional architectural paints used for the sameapplication.

Loss of gloss usually precedes chalking.

E-3 CHALKING

Chalking involves the release of one or more of theconstituents of the organic film in the form of looselyadherent fine powder. Chalking occurs slowly onpre-painted products and is not considered a seriousdefect unless it occurs early in the life of the product.

E-4 CHECKING

Checking is the formation of breaks in the surface ofan organic coating, which do not render the underlyingmetal visible. Although checking can occur in a numberof forms, it does not greatly detract from the appearance

ANNEX E(Foreword)

ADVICE ON THE WEATHERING PERFORMANCE OF THE PRE-PAINTED ALUMINIUM-ZINCALLOY METALIC COATED STEEL STRIP AND SHEET (PLAIN)

of a coating until the breaks become quite visible.Checking does not have a great effect on the durabilityof pre-painted metal products.

Slight checking, especially if it occurs during or aftercold weather, is not detrimental to the product, and isconsidered to be a means whereby internal stresses thatoccur from time to time are relieved.

E-5 COLOUR FADING

Although fading involves loss of colour, the term is usedto cover any colour change, including darkening. Thedegree and rate of loss of colour increase with increasein exposure to ultraviolet light (sunlight). Loss of colouris also associated with the inherent characteristics ofpigments and the exposure environment.

Discolouration by dirt collection, chalking andsubsequent absorption of foreign matter can often bemisleading and give a false impression of a colourchange. On removal of such contaminants the originalcolour is often restored. However, when chalking occursat the same time as fading, cleaning can seldom restorethe original surface colour.

E-6 EROSION OF ORGANIC COATINGS

Attrition of the organic coating by natural weatheringdepends very much on exposure conditions. Little orno erosion will occur when products are used indoorsin domestic dwellings.

Products installed at an angle can be expected todeteriorate at up to twice the rate that would occur forproducts installed vertically or otherwise sheltered fromthe elements.

In general, products installed at an angle will erodemore rapidly than those installed vertically.

The effects of dirt or industrial fallout can be greatlyreduced by natural rain washing or by general washingwith water. It is recommended that sheltered areas, suchas under eaves and those that receive little natural rain-washing, are periodically washed with clean water.

15

IS 15965 : 2012

ANNEX F(Foreword)

SUMMARY OF TESTS FOR PROPERTIES AND EXPECTED RESULTS

Sl No.

Tests Results Comments

i) T-bend adhesion test 5 t, Max See Annex A ii) Reverse impact test 10 J or 1020 kg. mm, Min See Annex B

iii) Pencil hardness test HB hardness, Min See 8.4 iv) Scratch resistance test

1.5 kg, Min Or as agreed between the manufacturer and the

customer. Not a part of the mandatory testing as mentioned in 8.5.

v) Solvent resistance test

50 Double rubs, Min The number of rubs required is dependent on the paint system of the top-coat. However the result is an indication of standard topcoat paint system (see Annex C).

vi) Dry film thickness test 15 µ, Min Or as per agreement between the manufacturer and the customer. This refers to the paint film thickness of the finish coat or top-coat.

vii) Colour Rating of 2, Max Rating classification for degree of colour match. (see Table 2).

viii) Gloss 10-40 per cent with 60° head (gloss geometry)

Gloss is dependant on the paint system. However the result is a typical range for a standard paint system. Or acceptable limit is as agreed to between the customer and the supplier.

ANNEX G(Foreword)

COMMITTEE COMPOSITION

Wrought Steel Products Sectional Committee, MTD 4

Organization Representative(s)

Tata Steel Ltd, Jamshedpur DR D. BHATTACHRJEE (Chairman)SHRI INDRANIL CHAKRABORTY (Alternate I)DR A. N. BHAGAT (Alternate II)

All India Induction Furnace Association, New Delhi SHRI L. N. GOSWAMI

Bharat Heavy Electricals Ltd, Tiruchirapalli SHRI V. RAJASEKHARAN

Central Boilers Board, New Delhi REPRESENTATIVE

Central Public Works Department, New Delhi CHIEF ENGINEER (NDR)SUPERINTENDING ENGINEER (NDR) (Alternate)

DGS & D, Bhilai Nagar/Delhi REPRESENTATIVE

Escorts Knowledge Management Centre, Faridabad SHRI ALOK NAYAR

Essar Steels Ltd, Hazira DR A. K. DASSHRI R. K. BALASUBRAMANIAM (Alternate)

Instiute of Steel Development and Growth, Kolkata SHRI JAYANTA KUMAR SAHA

Jindal South West Ltd, Vasind SHRI M. K. MAHESHWARI

M. N. Dastur & Co Ltd, Kolkata/Delhi SHRI SUBHABRATA SENGUPTASHRI V. K. TYAGI (Alternate)

Ministry of Defence (DGOFB), Kolkata SHRI P. S. BANDHOPADHYAYSHRI T. BASU (Alternate)

Ministry of Defence (DGQA), Ichapur SHRI S. K. KHILNANEYSHRI P. MEENA (Alternate)

16

IS 15965 : 2012

Organization Representative(s)

Ministry of Railways (RDSO), Lucknow SHRI RADHEY SHAMSHRI V. D. MEHARKURE (Alternate)

Ministry of Steel (Government of India), New Delhi SHRI A. C. R. DASSHRI B. D. GHOSH (Alternate)

Power Grid Corporation of India Ltd, Gurgaon SHRI K. N. M. RAOSHRI M. K. SETHI (Alternate)

Rashtriya Ispat Nigam Ltd (VSP), Vishakhapatnam SHRI P. K. SENSHRI P. SRINIVAS (Alternate)

SAIL, Bhilai Steel Plant, Bhilai SHRI S. BHATTACHARYASHRI P. K. DATTA (Alternate)

SAIL, Bokaro Steel Plant, Bokaro DR M. M. S. SODHISHRI P. S. REDDY (Alternate)

SAIL, Central Marketing Organization, Kolkata SHRI P. C. JHASHRI B. V. S. PANDIT (Alternate)

SAIL, Research & Development Center for Iron & Steel, Ranchi DR B. K. JHASHRI ATUL SAXENA (Alternate)

SAIL, Rourkela Steel Plant, Rourkela SHRI C. MUTHUSWAMYSHRI S. MUKHOPADHYAYA (Alternate)

Steel Re-rolling Mills Association of India, Mandi Gobindgarh SHRI B. M. BERIWALACOL SURINDER SINGH (Alternate)

Tata Motors Limited, Pune SHRI B. R. GALGALISHRI U. B. PATHAK (Alternate)

Tata BlueScope Steel Ltd, Pune SHRI RAJESH MAHESHWARISHRI SANJAY SARASWAT (Alternate)

TCE Consulting Engineers, Jamshedpur DR M. D. MAHESHWARI

BIS Directorate General DR (SHRIMATI) SNEH BHATLA, Scientist ‘F’ and Head (MTD)[Representing Director General (Ex-officio)]

Member SecretarySHRI DEEPAK JAIN

Scientist ‘E’ (Director) (MTD), BIS

Flat Steel Products Subcommittee, MTD 4 : 3

TCE Consulting Engineers, Jamshedpur DR M. D. MAHESHWARI (Convener)

Bhushan Power and Steel Ltd, Hooghly SHRI P. S. PAUL

Federation of Engineering Industries of India, New Delhi SHRI H. L. BHARDWAJSHRI H. L. BANSAL (Alternate)

Indian Oil Corporation Limited, Noida SHRI M. K. JHASHRI T. BANDHOPADHYAY (Alternate)

Ispat Industries Limited, Dolvi SHRI RAMBRIKSH SINGHSHRI RAJENDERA K. VERMA (Alternate)

Metal Containers Manufacturers Association, New Delhi SHRI SANJAY BHATIASHRI DIWAKAR SHETTY (Alternate)

SAIL, Bhilai Steel Plant, Bhilai SHRI A. DASGUPTASHRI K. L. BALASUBRAMANAIAN (Alternate)

SAIL, R&D Centre for Iron & Steel, Ranchi SHRIMATI ANJANA DEVA

SAIL, Salem Steel Plant, Salem SHRI S. S. SISODIA

Tata Motors Limited, Pune SHRI V. HARIHARAN

Tata Steel Ltd, Jamshedpur SHRI M. S. HOME

The Tin Plate Company of India Ltd, Jamshedpur SHRI T. K. GHOSHSHRI A. K. GHOSH (Alternate)

Thyssenkrupp Electrical Steel India Pvt Ltd, Nashik SHRI J. SREENIVASSHRI KAPIL KAPOOR (Alternate)

Welspun Corp Ltd, Anjar SHRI B. LAKSHMINARASIMHAM

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goodsand attending to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publications), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of‘BIS Catalogue’ and ‘Standards : Monthly Additions’.

This Indian Standard has been developed from Doc No.: MTD 4 (4856).

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters:

Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002Telephones : 2323 0131, 2323 3375, 2323 9402 Website: www.bis.org.in

Regional Offices: Telephones

Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg 2323 7617NEW DELHI 110002 2323 3841

Eastern : 1/14 C.I.T. Scheme VII M, V. I. P. Road, Kankurgachi 2337 8499, 2337 8561KOLKATA 700054 2337 8626, 2337 9120

Northern : SCO 335-336, Sector 34-A, CHANDIGARH 160022 60 384360 9285

Southern : C.I.T. Campus, IV Cross Road, CHENNAI 600113 2254 1216, 2254 14422254 2519, 2254 2315

Western : Manakalaya, E9 MIDC, Marol, Andheri (East) 2832 9295, 2832 7858MUMBAI 400093 2832 7891, 2832 7892

Branches: AHMEDABAD. BANGALORE. BHOPAL. BHUBANESHWAR. COIMBATORE. DEHRADUN.FARIDABAD. GHAZIABAD. GUWAHATI. HYDERABAD. JAIPUR. KANPUR. LUCKNOW.NAGPUR. PARWANOO. PATNA. PUNE. RAJKOT. THIRUVANANTHAPURAM.VISAKHAPATNAM.

�

��

�

�

Published by BIS, New Delhi