AN INTRODUCTION TO

CSWIP 3.1

By

MR ANSAR BALOCH

Contents

Terms & DefinitionTypes of WeldsTypes of JointsWeld PreparationsTypes of Single Butt PreparationButt Welded JointFillet Weld ProfileEffect of a Poor Toe Blend AngleSummary of TermsDuties of Welding InspectorResponsibilities of Welding InspectorImperfections in Welded JointsMechanical TestingMacro Inspection

A Joint:* A configuration of members

A Weld:* A union between materials caused by heat, and or pressure

Text Page Ref 1:1

Butt welds:*

Fillet welds:*

Spot/Seam welds:*

Plug/Slot welds:*

Edge welds:*

Closed corner

Open corner*

T joints: *

Lap joints: *

Corner joints:*

Butt joints: *

Angle of bevel*

Included angle*

Root gap*

Root face*

Root radius*

Root landing*

Single V

Single bevel

Single J

Single U*

Double bevel

Double V

Double J

Double U*

A butt welded butt joint*

A fillet welded butt joint*

A compound welded butt joint*

A butt welded T joint*

A fillet welded T joint*

A compound welded T joint*

A compound welded Lap joint*

A spot welded Lap joint*

A fillet welded Lap joint*

A butt welded Closed Corner joint*

A fillet welded Closed Corner joint*

A compound welded Closed Corner joint*

An outside fillet welded Open Corner joint*

An An inside filletinside fillet welded Open C welded Open Corner jointrner joint**

A double fillet welded Open Corner joint*

1 2

43

A

B

A + B = Excess Weld Metal**

Weld Face*

Weld Width*

Design Throat Thickness*1.2.3.4. Weld Toes*

Weld Root*HAZ*

Actual Throat Thickness*

 

Weld face*

Vertical Leg Length*

Horizontal Leg Length*

Design throat*Actual throat*

Excess weld metal **

80°

20°

6 mm

3 mm*

Very Poor Weld Toe Blend Angle

Improved Weld Toe Blend Angle

Extremely poor toe blend, but excess weld metal is within limits*

3 mm90°

Weld Sizing (Fillets): DTT. ATT. Excess weld metal. Leg length *

Weld Sizing (Butts): DTT. ATT. Excess weld metal.

Weldment Terms: Weld face & root. HAZ. Weld toes.Weld width

Preparation Terms: Bevel/included angle. Root face/gap. Land/Radius

Types of Preparation: Bevel’s. V’s. J’s. U’s. Single & Double Sided.

Types of Joint: Butt. T. Lap. Corner (Open & Closed)

Types of Weld: Butt. Fillet. Spot. Seam Plug. Slot. Edge.

Weld Preparation: Preparing a joint to allow access and fusion.

Joint: A Configuration of members

Weld: A Union of materials

It is the duty of all welding inspectors: To ensure that welding operations are carried out in accordance with written, or agreed practices or specifications

Before

During

After

*

Discuss the following

1) Safety:

Rules.

2) Documentation: Spec. Drawings. Procedures. Welder approvals. Certificates. Mill sheets

3) Welding Process and accessories: Equipment,Cables, Regulators, Ovens etc

4) Incoming Consumables:

Materials/welding consumables (Size. Condition. Specification. Storage)

5) Marking out preparation & set up: Method. Angles/Root face/gap values. Distortion control. Pre-heat prior to tack welding if applicable*

Before Welding:

During Welding:

1) Pre-Heating (Min 15 C as per UW-30 ASME Section VIII Div-I)

2) In process distortion control (Balance or sequence welding)

3) Consumable control. (Correct baking for E-7018 260-425 C and storage 30-140 C prior to use)

4) Welding process (Related parameters i.e. volts/amps. gas flow rate)

5) Welding run sequence and inter-pass cleaning

6) Minimum/maximum Inter-pass temperatures (150 C for SS, 250 C for CS.

7) Full compliance with all elements given on the WPS*

After Welding:

1) Visual Inspection

2) Non Destructive testing

3) Repairs*

4) Repair procedures (NDT/Welding/Welder approval)

5) PWHT

6) Hydro-static testing

7) Submission of all inspection reports to QC departments*

To Record

To Compare

To Observe Activities & Imperfections*

Activities & Imperfections*

Activities & Imperfections*

A Welding Inspectors toolbox should contain*

A welding gauge (Cambridge style, or high low gauges etc)

A tape measure and scale

A wire brush

A magnifying glass

A torch and mirror

A specification, pen and report, or note paper

Welding imperfections can be categorized into groups:

3) Solid Inclusions

4) Lack of fusion

1) Cracks

6) Mechanical or Surface damage

5) Profile & Lack of Filling

2) Gas Pores & Porosity

7) Misalignment*

A HAZ hydrogen crack, initiated at the weld toe

Most cracks are initiated from stress concentrations *

Surface breaking porosity

Fine cluster porosity Blow hole > 1.6 mm Ø

Hollow root bead 

An isolated internal porosity

Coarse cluster porosityShrinkage cavity* 

Internal solid inclusion causing a lack of sidewall fusion

Surface breaking solid inclusionInternal solid inclusion causinga lack of inter-run fusion*

Solid inclusions caused by undercut in the previous weld run

Internal solid inclusion

Lack of root fusion

Overlap (Causing cold laps)

Lack of inter-run fusion Lack of sidewall fusion

Lack of sidewall fusion & incompletely filled grove*

An Incompletely filled groove

Lack of root fusion

Spatter

A

Poor toe blend

Bulbous, or irregular contourArc Strikes

Incomplete root penetration

B

*

Root Run or “Hot pass” undercut

Parent metal, surface undercut 

Weld metal, surface undercut*

 

Weld metal, surface undercut Parent metal, “top toe” undercut*

Any surface damage caused by:

Grinding

Hammering/chisel marks

Slag chipping hammer marks

Arc strikes

Linear misalignment measured in mm (over 13mm to 19mm as per UW 33 of ASME Sec VIII Div-I)

3 mm

Angular misalignment measured in degrees*

15

Excess weld metal heightLowest plate to highest point

Linear

Angular

Why ?* To establish the level of mechanicalTo establish the level of mechanical propertiesproperties*

Which properties ?*

4) Ductility*3) Tensile strength*

2) Toughness (Impact Test)*

1) Hardness*

We test welds to establish minimum levels of mechanical properties, and soundness of the welded joint*

We divide tests into Quantitative & Qualitative methods:*

1) Quantitative tests: (Have units)*1) Quantitative tests: (Have units)*

2) Qualitative tests: (Have no units)*2) Qualitative tests: (Have no units)*

Types of tests include:

1) Quantitative tests:

Hardness tests

Toughness tests

Tensile strength tests*

1) Quantitative tests:

Hardness tests

Toughness tests

Tensile strength tests*

2) Qualitative tests:

Macro tests

Bend tests

Fracture tests*

2) Qualitative tests:

Macro tests

Bend tests

Fracture tests*

The specimen below has been polished and is ready to be hardness tested

= Hardness Survey

Thickness

Base metal HAZ Fusion boundary Weld metal

Generally we use a diamond or steel ball to form an indentation

We measure the width of the indentation to gauge the hardness*

1)1) Vickers Diamond Pyramid:Vickers Diamond Pyramid: Always uses a diamond*

2)2) Brinell hardness test:Brinell hardness test: Always uses a steel ball*

3)3) Rockwell hardness test:Rockwell hardness test: Uses a ball, or diamond depending on the scale*

10 x 10 mmMachined notch

Pendulum Hammer

Location of specimen

The specimen may be tested from different areas of the weld.*

Graduated scale of absorbed energy in Joules*

1)1) Charpy V test:Charpy V test: 10 x 10 (Specimen horizontal) Joules*

2)2) Izod test:Izod test: 10 x 10 (Specimen vertical) Ft.lbs*

Weld

  HAZ

 

Plate material

 

Test gripping area

 

Radius (For radius reduced test specimens only)

 

Reduced Section

 

Used to assess the tensile strength of the weld metal

Direction of test

 

Tensile test piece cut along weld specimen.

Direction of the test *

All Weld Metal Tensile Testing

Firstly, before the tensile test 2 marks are made 50mm

During the test, Yield point & Tensile strength are measured

The specimen is put together and the marks are re-measured

A new measurement of 75mm will indicate Elongation E50 %*

50 mm

75 mm

3) Lack of Root Fusion

1) Excess Weld Metal Height 7) Poor Toe Blend*

4) Slag inclusion & Lack of inter-run fusion

2) Lack of Sidewall Fusion5) Root Penetration

6)Porosity

Bend tests are used to establish fusion in the area under test

FormerTest Piece

Lack of root fusion shown here*

Further tests include face, side and longitudinal bend tests*

For material over 12 mm thickness, side bend test may be used*

Force

A Guided root bend test*Guide

Specimen prior to test* Specimen after test*

The main difference between Macro & Micro is that Micro is the study of the micro-structure at much higher magnification

The limit of Macro inspection is magnification < X 10

The specimen is usually cut from a stop/start in the test piece

Remember! The process of inspection is to first:

Observe, then Report, then Compare!*