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QIWS/001 - Tungsten Arc Gas Shielded Welding

Tutor Pack

EAL Level 1 Award in Introductory Welding Skills Unit: QIWS-001 – Tungsten Inert Gas Shielded Welding (TIG)

Issue1.0

QIWS/001 – Tungsten Inert Gas Shielded Welding - 2 -

Contents

Page

Section 1 : Introduction

3

Section 2 : Guidance on assessment

4

Section 3 : Self study pack

5

Section 4 : Welding procedure specifications and assessment sheets

17

Section 5 : Knowledge questions

27

Section 6 : Knowledge answers

30

Section 7 : Declaration of completion

33


Section 1: Introduction This self study booklet is provided to support your learning and prepare you to complete the knowledge

questions provided. You should read this and complete it with support from your tutor and upon

completing the qualification you should retain the booklet as a useful resource about the welding

process you have completed. It also contains the Welding Procedure Specifications (WPS) that detail the

requirements of the 5 five practical tests you must attempt to complete the qualification.

During this qualification you will develop the practical skills required to perform Tungsten Inert Gas

Shielded Welding (TIG) welding in the flat and horizontal/vertical positions. You will produce welds and

visually assess that they are fit for propose against the requirements of the weld procedure (WPS)

provided within the unit internal assessment. Furthermore you will learn the fundamental underpinning

knowledge relevant to the TIG welding process including, safety, use of equipment and choice of

consumables.

This Qualification is intended to provide a level of knowledge that will allow fundamental welding to

take place safely and provide the base level of knowledge and skill to allow progression onto level 2

qualifications.

This booklet covers the six learning outcomes of the qualification:

Learning outcome:

Assessment method:

1. Produce beads on plate in the PA flat position

Practical task

2. Produce a lap fillet weld in the PB horizontal/vertical position

Practical task

3. Produce a tee fillet weld in the PA flat position

Practical task

4. Produce a tee fillet weld in the PB horizontal/vertical position

Practical task

5. Produce a corner weld in the PA flat position

Practical task

6. Know the Process and Health & Safety requirements of TIG welding

Knowledge test

All the assessments must be competed in line with the assessment guidance provided and signed off by your tutor. All work should be retained for inspection by the EAL External Verifier if requested.


Section 2: Guidance on Assessment Guidance on the completion and assessment of the welds

1. All welding plate blanks to be at least 150mm by 50mm

2. All TIG welding tests to be completed using1.0 – 3.0mm Low Carbon Steel

3. All welds to be single run

4. No stop start requirements on tests (however it is recommended this is practiced)

5. All weld testing is visual only (however it is recommended macro etch is demonstrated)

6. All weld assessment must be recorded on the provided sheet and retained

7. Tasks should take no more than 45 minutes

Guidance on the completion of the knowledge questions

1. All questions must be attempted

2. This is an open book assessment

3. Any questions completed incorrectly must be discussed verbally with your tutor until they are satisfied you have understood

4. Answer sheets should be signed off and retained


Section 3 : Self study pack

Learning Outcome 6: Know the Process and Health & Safety requirements of TIG welding

Process description:

A welding power source supplies a welding current to create an electric arc between a tungsten electrode and the surface of the metals to be joined.

This welding current can be set at a D.C. current for steel and stainless steel or an A.C. current for aluminum.

The arc is struck by using a high frequency charge and the tungsten electrode does not touch the surface of the metals to be joined. If it does it becomes contaminated and must be re-sharpened.

The heat of the arc melts the metal to form a molten weld pool.

An inert shielding gas is used to protect the weld from contamination; the gas is

released as the arc is initiated.

The welder manually adds a filler rod into the molten pool as welding progresses by dipping the filler rod into the molten pool. The quality of the finished weld is dependant how well this is done.

TIG welding is a skilled welding process that relies on a high level of manual dexterity.

It is particularly suitable for high quality welding on a range of aluminum and stainless steels. It is used extensively in the welding of aerospace, marine and food processing equipment. It also used to weld the root runs on multi process pipe welding.

Further information on TIG welding can be found at

http://www.twi.co.uk/content/jk6.html

http://en.wikipedia.org/wiki/Welding_power_supply

http://en.wikipedia.org/wiki/Electric_arc



Health and Safety with TIG There are hazards associated with TIG welding. (Discuss each with your tutor and consider what actually causes the danger and how you can reduce the danger to your self and others whilst welding)

High Frequency

Arc Compressed

Gas Cylinders

Hot metal And

Burns

Fire and Explosion

WeldingFumes

and Noise

Arc Radiation

Electric Shock

Hazards


!)

Personal Protective Equipment (PPE)

Protect yourself and others from Arc Radiation and Burns by wearing and using the correct PPE!

Wear the correct welding helmet with the correct grade of filter glass fitted (check it

Wear leather TIG gloves, welding overalls and steel toe capped boots in good serviceable condition

Exposure to welding arc can cause:

Skin burns like a very bad sunburn (ultra violet light) Fatigue and tiredness (infra red light) Arc eye (severe irritation to the eye –watering eyes and partial loss of vision), occurs 4-

8 hours after exposure and painful Beware of arc radiation from reflective surfaces Use screens around your work area to protect others


degreased

Protect yourself from excessive noise- welding can be noisy!

ocess and grinding can generate noise ensure you wear ear protection if necessary

Protect yourself and others from electric shocks- they can be fatal!

emove rings and metallic watch straps

ear protective clothing including overalls and insulating safety boots

tand or kneel on a dry surface when welding

nly use a TIG torch in good condition

Do not weld in the rain without a suitable cover

Protect yourself and others from fire – fires start easily!

Protect yourself and others from fumes – by using the correct extraction!

Welding fumes can cause lung irritation and long term lung damage

Make sure fume extractors are working and positioned correctly (ask you tutor to show you)

Welding materials must be clean and

Welding pr

R

W

S

O


Remove any flammable material from the welding area Beware of containers that may have contained flammable materials Know wh extinguishers are kept (for use onelectrical equipment) Ensure y

ere CO2 or powder fire

our tutor has explained to

are of fire exits and the

evacuation procedure

ype and use of fire extinguishers – learn the right extinguisher for the right job

you how to use the correct type of fire extinguisher

Be aw

T

Extinguisher Type (Coloured ban red bod white wrd on y with iting)

Water Foam Powder CO 2 Class of Fire

Paper, Wood, Textiles, Fabric

Flammable Liquids

Flammable Gases

Electrical Equipment

Transport, Domestic eg boats, cars, caravans, the home


Explosions – consider what you are actually welding!

There is a great danger of explosion or fire when welding containers that have previously contained explosive or flammable substances, such as petrol or oil; flammable materials can be trapped in:

grooves seams riveted joints

Never weld old oil cans or petrol tanks unless before welding, the following action must be carried out:

Remove explosive materials by steaming out with a low pressure steam cleaner and before welding the atmosphere inside the container must be certified as safe.

Compressed gas cylinders – always treat with respect! Cylinders of compressed gas must always be treated with respect; great care should be taken in moving them around the workshop, connecting them to welding equipment and in their storage. Safety rules include: Moving cylinders

Always use an approved type of cylinder trolley to move cylinders

Never move cylinders with their regulators attached

If necessary to move by hand it should only be over short distances

Always ensure your pathway is clear before starting to move a cylinder

Never move cylinders over cables etc


Safety signs - protect yourself and others

Prohibition signs – must be obeyed Circular signs with red surround and diagonal red line.

NO SMOKING

Mandatory signs – must be carried out Circular blue signs

WEAR EYE PROTECTION

Warning signs – warns of hazard or danger Yellow triangular signs with black symbol and surround

DANGER HIGHLY FLAMMABLE

Information signs – to advise Green square signs

FIRE EXIT

All taken from http://www.onlinesign.com/build_sign.php?pic=58

http://www.online-sign.com/pictogram_�

http://www.onlinesign.com/build_sign.php?pic=58


What equipment do you use for TIG welding?

Ask your tutor to show you and identify each equipment

component listed below.

(PPE) Personal protective

equipment Gloves

Welding helmet Boots

Overalls

TIG power source (power source)

Conduit/harness Welding torch Return lead Gas cylinder Regulators Flow meter

Consumables Tungsten electrodes

Filler wire Shielding gas

Tools and equipment Wire brush

Work bench Welding booth and

curtains Extraction

The TIG Power Source Current control: The current can be controlled by using a dial on the welding machine. The current will vary according to the thickness of the metal.


TIG welding set (power source) TIG power sources mostly use a transformer rectifier. This type of power source creates an AC welding current and rectifies it to a DC welding current. The DC welding current is used for steel and stainless steel and the A.C. current for aluminum. The power source has a control so you can choose which type of current you need. (A rectifier is an electrical device which converts alternating current (AC) to direct current (DC) this process is known as rectification.) Once the TIG welding machine has been set up correctly, it will provide the correct power for the TIG welding process.

Electrical connections There are two cables connected to and from the welding machine:

the welding lead (harness or conduit) the welding return attached to the return clamp

The welding machine will have its own separate electrical earth lead. TIG welding torch (ask your tutor to show you these components) The welding torch can be air or water cooled and is made up of the:

collet ,collet holder and backcap (to insulate and grip the tungsten electrode)

gas lense (which focuses the gas glow) ceramic shroud (guides the shielding gases onto the

welding area) tungsten electrode nozzle (made out of heat resistant material)

http://en.wikipedia.org/wiki/Alternating_current

http://en.wikipedia.org/wiki/Direct_current


17.html

Ignition switch/foot control The current to the welding torch can be controlled by the ignition switch on the torch body or from a remote foot control

Shielding Gas The shielding gases used for TIG welding are pure argon or helium/argon mixture, which are supplied in cylinders or piped directly into the workshop. The pressure regulator on the cylinder allows the operator to adjust the gas flow rate for the type of welding. There is a flow meter on the cylinder to allow find adjustment and show the flow rate.

Tungsten Electrode The tungsten electrode is made from tungsten or a tungsten alloy, tungsten has the highest melting temperature among pure metals, at 3,422 °C (6,192 °F). As a result, the electrode is not consumed during welding, though some erosion can occur.

Tungsten electrodes need to be ground to a specific point shape to suit the current being used. They can be ground freehand or using a special grinding machine. (Ask your tutor to show you how they are sharpened)

Filler wire The welder may add filler wire into the molten pool as welding progresses. The filler wire will be made of the same metal as the materials being welded. It is normally supplied in large sealed plastic tubes. Steel wire will be coated in copper to protect from corrosion.

Further information on TIG welding equipment can be found at http://www.twi.co.uk/content/jk



Starting to Weld

Striking the arc:

set the power source up in terms of current type and level relevant to material thickness

hold the tungsten approx 3-4mm above the surface of the work press the foot pedal (if using foot control) or the switch on the torch the high frequency will automatically start the arc .

Making a good weld relies on:

using the correct diameter and type of filler wire using the correct shielding gas type, flow and pressure rate using the correct current type (AC or DC) keeping the arc length consistent consistent speed and angle of tungsten tip movement along the plate feeding the filler wire in a regular and uniform way making smooth joins when stop and start mid way through a weld


Possible defects with welds

Defect name Possible reason for defect

Poor weld appearance Bad technique or machine not set up correctly – check with your tutor

Tungsten inclusion Poor technique allowing the tungsten to touch down

Undercut Poor technique - ask your tutor to show you

Lack of fusion/penetration Poor technique or settings too low

Porous weld Lack of shielding gas or dirty plate - check flow meter and material cleanliness

Weld too wide or too narrow

Poor technique, moving too fast or too slow- ask your tutor to show you

Parts of a fillet weld

The different areas of a fillet weld are named to allow them to be identified and measured against any weld standards. The leg length gives you the size of the fillet, so if the leg length measured 5mm you would have a 5mm fillet weld.


Section 4 : Welding procedure specifications and assessment sheets

Welding Procedure Specification:

Learning Outcome 1 – Beads on Plate in the flat (PA) position (TIG)

Joint type: Beads on plate

Welding position: PA

Parent Material Type: Low carbon steel (LCS)

Dimension of test piece:

Thickness: 1.0 -3mm.

Length: 150mm minimum.

Width: 50mm minimum

Weld preparation Plates should be degreased and wire brushed prior to welding

Run sequence and completed weld

Method of Preparation and Cleaning: Degrease / mechanical dressing / wire brush.

Run No. Tungsten Electrode dia

Amperage (range)

Arc Voltage (range)

Polarity Gas Flow Rate:

1 2.4mm 80 -120 12-15 dc -ve 5 – 8 litres/min

Other Information: Two parallel weld beads to be completed for full length of plate There is no requirement to complete a stop start on this w but if one is attempted it will be assessed along with

Remo g and sp ean w br rind fi ld surfacdamage.

eldthe weld.

ve any sla atter and cl eld with wire ush, do not g nished we e, avoid surface

Welding Consumables:

Filler material: Suitable carbon steel solid wire Visual ex

Composition: In accordance with BS EN440: 1995

Shielding gas: Argon

Non destructive testing:

amination only – details on assessment sheet


Learning Outcome 1 – Beads on Plate in the flat (PA) position (TIG)

All essen rabletial items and 2 from 3 desi must pass assessment

Learner name: Date of completion:

Decision Pass Fail Assessor Comments 1. Uniformity The weld is uniform and width does not vary more than 4mm along length (desirable)

The weld toes blend without cold lapping (essential)

The weld reinforcement is of even height along weld length (essential) The weld is free from cracking (essential)

No single cavity or inclusion is more than 3mm in any direction or any group more than 3m in total (essential)

2. Undercut Undercutting (intermittent) does not exceed 1.5mm depth (desirable) Undercutting does not exceed 50% of total weld length(desirable) No single undercutting exceeds 25mm (desirable)

Assessor General Comment

Assessor Signature

Learner Signature

Pass Mark (delete as appropriate) Task Pass/Fail

Date of re-assessment (if applicable)


edure Specificati n:

fille ontal/vertic l (PB) position (TIG)

Welding Proc o

Learning Outcome 2 – Lap t in the horiz a

Joint type: Lap fillet

Welding position: PB


Dimension of test piece:

Thickness: 1.0 -3mm.

Length: 150mm minimum.

Width: 50mm minimum

Weld preparation


Method of Preparation and Cleaning: Degrease / mechanical dressing / wire brush.


Amperage (range)

Arc Voltage (range)

Polarity Gas Flow Rate:


Other Information: Ensure plates are clamped and tack welded prior to welding There is no requirement to complete a stop start on this weld but if one is attempted it will be assessed along with the weld.

Remove any slag and spatter and clean weld with wire brush, do not grind finished weld surface, avoid surface damage. Welding Consumables:

Filler material: Suitable carbon steel solid wire



Non destructive testing: Visual examination only – details on assessment sheet


Learning Outcome 2 – Lap fillet in horizontal/vertical (PB) position (TIG)

A

ll essential items and 3 from 5 desirable must pass assessment

L n: earner name: Date of completio

Decision Pass Fail Assessor Comments 1. Alignment Linear misalignment should not exceed +/- 3mm of c )

entre line (desirable

2. Uniformity The weld is uniform and width does not vary more than +/- 3mm along length (desirable)

Leg length must not exceed metal thickness + 2mm (essential)


The weld reinforcement is of even height along weld length (essential)

The weld i

s free from cracking (essential)

No single cavity or inclu an 3a or any group an 3m in(

sion is more th mm in ny direction more th total essential)

3. Undercut Udepth (desirable)

ndercutting (intermittent) does not exceed 1.5mm

Ul rable)

ndercutting does not exceed 50% of total weld ength(desi

N

o single undercutting exceeds 25mm (desirable)


A ssessor Signature

Learner Signature




Learning Outcome 3 – Tee fillet in the flat (PA) position (TIG)


Joint type: Tee fillet Dimension of test piece:

Welding position: PA


Thick

: 150mm minimum.

idt m

ness: 1.0 -3mm.

Length

W h: 50m minimum

Weld preparation


450

Method of Preparation and Cleaning: Degrease / mech ical dressing / e brush. an wir

Run No. Tungsten Amperage )

Arc Voltage (range)

Polarity Gas Flow Rate: Electrode dia (range


Other Informa

tion:

welding

on th weld b f one i attempted it will be assessed along with

re rush, do not grind finished weld surface, avoid surface damage.

Ensure plates are clamped and tack welded prior to There is no requirement to complete a stop startthe weld.

is ut i s

Remove any slag and spatter and clean weld with wi b


aterial: Suitable carbon steel solid wire

In accordance with BS EN440: 1995


Filler m

Composition:



L e flat (PA) position (TIG)

A

earning Outcome 3 – Tee fillet in th

ll essential items and 3 from 6 desirable must pass assessment

L n: earner name: Date of completio

Decision Pass Fail Assessor Comments 1. Alignment Linear misalignment should not exceed +/- 3mm of c )

entre line (desirable

Angular alignment is within +/_ 50 from 900

(desirable)




The weld rel

inforcement is of even height along weld ength (essential)

The w rom crac al)

eld is free f king (essenti

N ity or inclusio e than 3a roup more than 3m in total (esse

o single cav n is mor mm in ny direction or any g

ntial) 3. Undercut Undercutting (intermittent) does not exceed 1.5mm d

epth (desirable)

U does not exceed 50% of total weld l

ndercuttingength(desirable) N ndercutting exceeds 25mm (desirable)

o single u


Assessor Signature

L earner Signature





Learning Outcome 4 – Tee fillet in the horizontal/vertical (PB) position (TIG)

Joint type: Tee fillet

PB

ype: Low carbon steel (LCS)

n of test piece:

ckn 1.0

Lengt 150mm minimum.

Width 50mm minimum

Welding position:

Parent Material T

Dimensio

Thi ess: -3mm.

h:

:

Weld preparation

Run sequence a d completed weld

n

Method of Preparation and Cleaning: Degrease / mech ical dre sing / wire brush. an s

Run No. Tungsten Amperage

Arc Voltage (range)

Polarity Gas Flow Rate: Electrode dia (range)


Ot er Inforh mat

ion:

el ing

on thi ld bu if one is will be assessed along with

ire brush, do ot grind shed weld surface, avoid surface damage.

Ensure plates are clamped and tack welded prior to w

d

There is no requirement to complete a stop start the weld.

s we t attempted it

Remove any slag and spatter and clean weld with w n fini


iller material: Suitable carbon steel solid wire

dance with BS EN440: 95


F

Composition: In accor 19



orizontal/vertical (PB) position (TIG)

Learning Outcome 4 – Tee fillet in h

All essential items and 3 from 6 desirable must pass assessment


Decision Pa mments ss Fail Assessor Co1. Alignment Linear misalignment should not exceed +/- 3mm of

le)

centre line (desirabAngular alignment is within +/_ 50 from 900

(desirable)




The weld reinforcement is of even height along weld length (essential)

The w from cra ntial)

eld is free cking (esse

No single cavity or inclusi re than 3group more than 3m in total

on is mo mm in any direction or any

ntial) (esse3. Undercut Undercutting (intermittent) does not exceed 1.5mm depth (desirable) Undercutting does not exceed 50% of total weld length(desirable) No single undercutting exceeds 25mm (desirable)


Assessor Signature

Learner Signature





Learning Outcome 5 – Corner weld in the flat (PA) position (TIG)

Joint type: Outside corner

elding position: PA

t Material Type: Low carbon steel (LCS)

Dimen

ss: 1.0

gt mm

Width 50mm minimum

W

Paren

sion of test piece:

Thickne -3mm.

Len h: 150 minimum.

:

Weld preparation


Method of Preparation and Cleaning: Degrease / mech ical dre sing / wire brush. an s


Amperage (range)

Arc Vol age (range)

Polarity Gas Flow Rate: t


Other Information:

lamped and tack welded prior to welding

hi ld bu if one is will be assessed along with

Remove any slag and spatter and clean weld with wire brush, do not grind shed weld surface, avoid surface

Ensure plates are c There is no requirement to complete a stop start on t s we t attempted it the weld.

finidamage. Welding Consumables:

iller material: Suitable carbon steel solid wire



F



in the flat (PA) position (TIG)

Learning Outcome 5 – Corner weld

All essential items and 4 from 7 desirable must pass assessment


Decision Pa mments ss Fail Assessor Co1. Alignment Angular alignment is within +/_ 50 from 900 (desirable) 2. Uniformity The weld is of uniform width of face (desirable)

The weld ripples are consistent and without excessive undulation (essential)


The weld profile is rounded (essential)

The weld is free from cracking (essential)

No si or inclu e thanany d r any gr 3m

ngle cavityirection o

sion is moroup more than

3mm in in total

(essential)

3. Undercut Undercutting (intermittent) does not exceed 1.5mm

depth (desirable)

Undercutting does not exceed 50% of total weld length(desirable)

No single undercutting exceeds 25mm (desirable)


Assessor Signature

Learner Signature




Section 5 : Knowledge questions TIG Welding

1. Complete the diagram showing the main hazards of TIG welding.

. List the main items of PPE and clothing to be worn during TIG welding.

2

Continued on next page

High reque cy

cF n

Ar

Hazards


3. Identify the type of weld in the diagram below.

Weld type is:……………………………………. Position is:……………………………………….

4. What is the purpose of the arc in TIG welding?

5. What is the main purpose of the active gas shield around the tungsten tip?

6. What are the consumables used in TIG welding?



. What are the main items of equipment used FOR TIG welding? Complete the diagram below.

. List the main defects found in TIG welds?

9. Which types of electrical current can be used for TIG welding?

0. Why is it important to erect screens around the welding area?

7

8

Ask your tutor to

below.

show you and identify each equipment

component listed

(PPE)

TIG power source

Consumables

Tools and equipment

1


Section 5 : Knowledge questions - solutions

1. List the main hazards of TIG welding.

) TIG welding gloves ) boots welding helmet

. Identify the type of weld in the diagram below.

orner weld in the PA flat position


High Frequency Arc

Electric Shock

Compressed Gas Cylinders

. List the main items of PPE and clothing to be worn during TIG welding. 2

abc)d) overalls

3 c

Hot metal And

Burns

Fire and Explosion

Welding d Fumes an

Noise

Hazards

Arc

Radiation


To produce heat to melt the filler rod and parent metal

gas shield around the tungsten tip?

To protect the weld from contamination

6. What are the consumables used in TIG welding?

filler rods Shielding gas

7. What are the main items of equipment used for TIG Welding? Complete the diagram below.

ontinued on next page

4. What is the purpose of the arc in TIG welding?

5. What is the main purpose of the active

Ask your tutor to show you and identify each equipment

component listed below.

(PPE) Personal protective

Welding helmet

veralls

TIG power source (power source)

return lead

Consumables Tungsten electrodes

gas cylinder regulators flow meter

Tools and equipment Wire brush

Work bench Welding booth and

curtains Extraction

equipment Gloves

Boots O

conduit/harness welding torch

Filler wire Shielding gas:

C


Poor weld appearance

Undercut Porous weld

r TIG welding?

0. Why is it important to erect screens around the welding area?

eople from Arc radiation

8. List the main defects found in welds?

Tungsten inclusion

Weld too wide or too narrow

9. Which types of electrical current can be used fo

AC and DC current

1 To protect other p


pletion – Unit 001 TIG

Section 7 : Declaration of com


Assessor name: Centre Name:

Task details Date completed

Assessor signature

1. Produce beads on plate in the PA flat position

2. Produce a lap fillet weld in the PB

horizontal/vertical position

3. Produce a tee fillet weld in the PA flat position

4. Produce a tee fillet weld in the PB horizontal/vertical position

5. Produce a corner weld in the PA flat position

6. Know the Process and Health & Safety requirements of TIG welding – knowledge test


Assessor Signature

Learner Signature

© 2011 EMTA Awards Limited All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of EAL EMTA Awards Limited Requests should be made in writing and addressed to: Product Development, EAL EMTA Awards Limited, 3365 Century Way, Thorpe Park, Leeds LS15 8ZB.

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