mem05012c perform routine mmaw · welder’s leather jacket. this offers the best protection from...

MEM05 Metal and Engineering

Training Package

Learner guide

Version 1

Training and Education Support

Industry Skills Unit

Meadowbank

Product code: 5521

MEM05012C Perform routine manual

metal arc welding

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© TAFE NSW (Training & Education Support Industry Skills Unit, Meadowbank)

2011

MEM05012C Perform routine manual metal arc welding

AcknowledgmentsThe TAFE NSW Training and Education Support Industry Skills Unit, Meadowbank would like to acknowledge the support and assistance of the following organisations and people in the production of this learner guide.

CIGWELDLincoln Electric Co.WIA

WriterEd Harkness (from existing TAFE resources)

ReviewerVince Aranda (Illawarra Institute)

Project ManagerStephen DaviesEducation Programs ManagerTAFE NSW

EnquiriesEnquiries about this and other publications can be made to:

Training and Education Support Industry Skills Unit, Meadowbank Meadowbank TAFE Level 3, Building J, See Street, MEADOWBANK NSW 2114

Tel: 02-9942 3200 Fax: 02-9942 3257

© TAFE NSW (Training and Education Support, Industry Skills Unit Meadowbank) 2011

Copyright of this material is reserved to TAFE NSW Training and Education Support, Industry Skills Unit Meadowbank. Reproduction or transmittal in whole or in part, other than for the purposes of private study or research, and subject to the provisions of the Copyright Act, is prohibited without the written authority of TAFE NSW Training and Education Support, Industry Skills Unit Meadowbank.

ISBN 978-1-74236-263-2

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© TAFE NSW (Training & Education Support Industry Skills Unit, Meadowbank)

2011


Table of Contents

Introduction ................................................................................... 7

1. General introduction ............................................................................. 7

2. Using this learner guide ......................................................................... 7

3. Prior knowledge and experience ............................................................. 9

4. Unit of competency overview ................................................................. 9

5. Assessment ....................................................................................... 12

Topic 1: The manual metal arc welding process ........................... 17

Safety .................................................................................................. 17

Review questions ................................................................................... 28

Practical jobs ......................................................................................... 30

Job 1 – Bead Welds ................................................................................ 32

Job 2 – Pad Welds .................................................................................. 34

Job 3 – Flat Fillet Welds........................................................................... 36

Job 4 – Horizontal/Vertical Fillet Welds ...................................................... 38

Job 5 – Multiple Run Horizontal/Vertical Fillet Welds .................................... 40

Job 6 – Multiple Run H/V Fillet Welds on Structural Sections ......................... 42

Job 7 – Corner Fillet Welds ...................................................................... 44

Job 8 – Butt Welds ................................................................................. 46

Resource Evaluation Form ............................................................ 49SAMPLE


© TAFE NSW (Training & Education Support, Industry Skills Unit Meadowbank) 2011 Page 17 of 52

Topic 1: The manual metal arc welding process

SafetyManual metal arc welding is a safe welding process provided it is used in the correct manner and strict welding safety guidelines are followed. As well as the operator, manual metal arc welding has the capacity to injure others in an area where welding is taking place.

Safety hazards include:

Burns

Burns occur when welding, the causes include;

• touching hot metal

• spatter, sparks or hot slag coming in contact with exposed skin or eyes

• heat of the arc.

Burns from welding can cause extreme discomfort and will often require fi rst aid attention.

Electrocution

Electric shock can occur due to:

• welding in damp or wet conditions

• contact with a non-insulated welding circuit

• using damaged welding plant or equipment

• body parts completing the welding circuit.

Electric shock from arc welding can cause serious injury or death.

Weld fumes

Fumes are given off from:

• the electrode fl ux coating melting in the arc

• oxides or the surface coating on metal parts being welded.

Weld fumes can cause discomfort after a short period of exposure. Some types of weld fumes can cause serious respiratory problems over a longer period of time. In general, weld fumes can cause respiratory problems for welding operators and others nearby.

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of 52 © TAFE NSW (Training & Education Support, Industry Skills Unit Meadowbank) 2011


Ultra-violet and infra-red rays/arc radiation

The welding arc emits especially strong ultra-violet and infra-red rays.

Ultra-violet (UV) rays are especially dangerous and will cause painful injuries to exposed skin and eyes.

Skin injuries are similar to sun burn. UV rays will cause eye injury to welding operators and others nearby, this painful condition is known as “welders fl ash” or “arc eye”.

Welders should be protected against infra-red rays exposure, as it has been associated with chronic damage to human lens.

Safety precautions

To protect yourself and others from injury, it is essential that the following welding safety precautions are followed:

Protective clothing and equipment

This includes:

• overalls or heavy drill cotton long trousers and long-sleeve shirt made from non-fl ammable material

• safety footwear with rubber soles

• welders leather gloves/gauntlets

• approved safety glasses or other eye protection when removing hot slag from a completed weld

– Australian standards approved welding face-shield/helmet with correct fi lter lens shade (e.g. shade 10-13; see table below)

• wearing standards approved safety glasses when working near welding operators.

Note: Clothing worn by the welding operator should be in good repair. Frayed clothing is a fi re hazard.

Never leave butane cigarette lighters in your pockets whilst welding as this can result in an explosion causing serious injury or death.

• Lightweight clothing is not suitable for the intense rays emitted from manual metal arc welding

• New clothing should be washed to remove starching agents which have been known to be fl ammable.

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Old, worn clothing should be discarded as the garment may readily ignite due to general wear, tear and deterioration of its fi bres.

Selection of fi lter lens

Shade of fi lter lens Recommended welding current (amps)10 Up to 150 amps

11 150-250 amps

12 250-300 amps

13 300-400 amps

14 Over 400 amps

Basic hand shield Standard head shield

Auto-darkening welding helmet

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of 52 © TAFE NSW (Training & Education Support, Industry Skills Unit Meadowbank) 2011


Protective clothing and equipment

An adjustable welding helmet allows the welder to view the arc in safety.

Auto-darkening welding helmets are now popular with welding operators

Welders' gauntlet gloves provide good protection from sparks, hot metal and the intense heat emittedfrom welding

Safety footwear protects the welder from the electrical hazards of welding, and hot sparks.

Steel toe-capped footwear will offer the operator protection from heavy falling objects

Welder’s leather jacket. This offers the best protection from heat and welding rays

Flame-proof

cotton clothing; trousers should NOT have cuffs as hot sparks may become trapped and cause clothing

Shirts should be long sleeved,

all pockets

Clear safety glasses should also be worn by all workers. They reduce the risk of eye injury when removing slag from hot welds and sparks from grinding

loose fitting

to catch fire.

with flaps covering

Additional student notes

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Welding screens

• In an open workshop or construction site, erect a welding screen made from non-refl ective material. This will protect others nearby from the harmful effects of the bright rays given off from the arc.

• It is important to warn others working nearby that welding is about to commence. Safety glasses should be worn at all times by both the welding operator and others working nearby.

Welding screens make workplaces safer for other workers

Electrical safety

Before turning on the welding machine:

• check all welding leads are in good condition

• make sure all electrical connections are tight and in good repair

• wear dry insulated safety footwear and work on a dry insulated fl oor where possible

• wear dry leather gloves

• do not change electrodes with bare hands or wet gloves

• never hold the electrode and holder under your arm

• never use welding equipment in a confi ned space or hazardous area without supervision by a competent person

• never place any part of your body in or across the welding circuit

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