welding training

8/14/2019 Welding Training

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Welding and inspection

Presented to the

people in need


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Course on

WELDING AND INSPECTION

Presentation on

Welding fundamentals,application , Symbol,inspection

An Overview

by

V UMASHANKAR

[email protected]

Chennai


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Introduction

Trainers background info

15Years in Welding Inspection by Visual and

NDT Heavy Equipment Fabrication Construction

equipment

Trainer in Manufacturing Quality, QMS,

Six sigma Green Belt, TPM Facilitator, QualityCircle Team Leader, Welding Quality, NDTUltrasonic testing and Quality concept.


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WELDING THEORY

Welding is joining two pieces of

materials.

Solid+solid Welding = Solid state bonding

Liquid+Liquid welding=Fusion Welding

Solid+Liquid Welding=Braze Welding

Oxy-Aceteline=Gas Welding

Thermit =

Atomic hydrogen=


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ELECTRICAL ENERGY

WELDING


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A) ELECTRICAL ARC

WELDING FCAW -Flux cored Arc Welding

CAW -Carbon arc Welding

SMAW -Shielded metal arc Welding

GMAW -Gas metal arc Welding

GTAW -Gas Tungsten arc Welding SW -Stud Welding

PAW -Plasma Arc Welding


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SHIELDED METAL ARC WELD


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SUBMERGED ARC WELDING


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Metal inert gas welding,MIG


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TUNGSTEN INERT GAS WELDING


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BRAZE WELDING


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B) ELECTRICAL

RESISTANCE WELDING Spot Welding

Seam Welding

Projection welding

Flash butt Welding

Electro slag Welding Stud Welding


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C) ELECTRICAL INDUCTION

WELDING Induction Presuure Welding

Induction Brazing


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MECHANICAL ENERGY

Friction Welding

Ultrasonic Welding,High freq sound waves

Explosive Welding


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SPECIAL SOURCE WELDING

Electron Beam Welding

Laser Welding


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ELECTRODE DAMAGE &

INFLUANCE Absorbtion or loss Moisture

Cracking & discaling covering

Contamination

Oxidation of the cored wire

Formation of deposits on the surface


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Absorbtion or loss Moisture

& INFLUANCE Porosity in weld metal

Excessive Projection

Spattering arc instability

Visual worsening of seam suface

Scouring / Blistering in cellulose coating Difficulty in removing slag

Cracking caused by hydrogen


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Formation of deposits on the

surface

Absorbtion or loss Moisture

Cracking & discaling covering

Contamination

Oxidation of the cored wire


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Welding inspection

Crack

Bead shift

Burn through

Porosity

Pin holes

Waviness Under cut

Weld appearance


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Weldments - Symbols and Drawing Practices


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DWGA130 Overview (Cont.)Primary Reference -

ISO 2553:1992

Secondary References -

AWS A2.4:1998


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Welding Symbol, Weld Symbol

FIGURE 1: Elements of a Welding Symbol


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Elementary Weld Symbols

Most common are fillet, square groove and

flare bevel weld joints


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Supplementary Weld Symbols

Contour symbols not used much in the past


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Weld Symbol Orientation

Reference lines and

weld symbol detailsremain the same

regardless of which

end the arrow is on.


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Weld Both Sides

Appropriate weld

symbols above and

below referencelines.

Dashed line not

required where theweld joint is

exactly symmetric.


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Combined Weld Symbols

More than

one weld

type. Size specified

individually

for each.


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Fillet Weld Size

Required minimum

weld size dimension(mm)z = leg dimension

a = throat dimension


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Butt/Groove Weld Size

Required minimum

throat dimension

(mm) No direct

measurement -

requires destructivetest and evaluation


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Intermittent Weld Dimensions

ISO vs AWS (App 2)

Size convention is the

same

Number and length of

segments

Spacing between

segments vs AWS ctr

to ctr method


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Symmetric Intermittent Weld

Same weld symbol

and dimensions

both sides Dashed line not

required

Anchor welds ateach end


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Staggered Intermittent Weld

Usually specified to

avoid weld distortion

or interference Offset dimension

specified in detail vs

default Anchor welds -

standard shop practiceZ denotes staggered

intermittent weld


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Intermittent Weld on Circular Part

If necessary, start location

must clearly be identified

Weld size

Number and length of

segments Spacing between segments

(chord dimension)


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Weld All Around

Simplified details

Exactly the same

joint conditions andwelds all the way

around


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Testing methods

Destructive

Mechanical,

Chemical,

Testing

Ultrasonic

TestingD P

Testing ,MPT,ECT,

X-RAY

AET,LEAK,

NRT,

Visual

inspection


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WELDINGSOUNDNESS

Good welding Practice summary

Right Welding

parameter at any time

No

Adjustment

Monitering

For right welding at first

Time and any time

Setting

With

errorproof

interlock

(Poka

yoke)


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Continuous Improvement ModelWelding parameter entry

RESULTRESULT

EVALUATIONEVALUATION

REPAIR,REPAIR,

IDENTIFYIDENTIFYACTION PLANAction Name Date

TIME

Trend Chart

GOAL

CheckCheck

PARETOANALYSIS100%

Set alingment


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Setting

TIME

CURRENT

WIRE

POSITION

DIFT

Wire feed

Input

Quality,

Good

Fittment,

Job

position,

Alingment

VOLTAGE

PM Good Welding


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GOOD WELDING CONTRIBUTION

MACHIN

E

34%

WELDER

16%

MATERI

AL

14%

OTHERS

9%

METHOD

27%


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CHECK POINTS

Rollequality

Spool quality

Alingnment

Torch setting

Flux baking

FITUP GAP

RUST

Input material

Quality

Machine

truness

Key Decisions Made

Ensure proper welding

parameterSet appropriate Time

Correct and monitor the process

Check incoming component

Clean and remove rust,oil

Ensure proper welding.


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Meet spec

Weld width

Penetration

Side wall

fusion

Quantum Improvement in

terms ofQuality

Cost

Cycle time

Leading Consultants for 6

and Cycle time Reduction

Clients:Citicorp, PwC, ICI,3M, Telstra

Requirement


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Six Sigmas definition of Defect


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NDE

Circumferentia

l Butt Weld

Inspection

ll welds shall be inspected. A weldsubject to inspection shall beacceptable if inspection shows:

a) No surface cracks

b) No Visible lack of fusionbetween welds and base metal

c) No craters

d) Uniform Weld profiles

e) That frequency of visibleporosity in fillet welds does notexceed one in each 100 mm oflength and the maximum diameterdoes not exceed 2.4 mm Thatgroove welds have no visibleporosity.

g) Undercut is not more than 0.5mm deep.

Repairable


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