MEM05004C Perform routine oxyacetylene welding … · Burns from welding can cause discomfort and...

MEM05 Metal and Engineering Training Package

Learner guide Version 1

Training and Education Support

Industry Skills Unit Meadowbank

Product Code: 5539

MEM05004C Perform routine

oxyacetylene welding

SAMPLE

MEM05004C Perform routine oxyacetylene welding

© TAFE NSW (Training & Education Support, Industry Skills Unit Meadowbank) 2012

Acknowledgments

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

� BOC Gases � CIGWELD

Writer Ed Harkness (from existing TAFE material)

Reviewer Vince Aranda (Illawarra Institute)

Project Manager Stephen Davies Educational Program Manager TAFE NSW

Enquiries Enquiries 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

ISBN 978-1-74236-275-5

© TAFE NSW (Training and Education Support, Industry Skills Unit Meadowbank) 2012

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 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.

SAMPLE


© TAFE NSW (Training & Education Support, Industry Skills Unit Meadowbank) 2012

Table of contents

Introduction .................................................................................. 5

1. General introduction ........................................................................... 5

2. Using this learner guide ...................................................................... 5

3. Prior knowledge and experience ........................................................... 7

4. Unit of competency overview ............................................................... 7

5. Assessment ..................................................................................... 10

Topic 1: Oxyacetylene welding safety .......................................... 15

Weld fumes ........................................................................................... 15

Use protective clothing and equipment (PPE) ............................................. 16

Review questions .................................................................................... 20

Topic 2: The oxyacetylene welding process .............................. 23

Equipment ............................................................................................. 24

Review questions .................................................................................... 31

Practical jobs ............................................................................... 35

Job 1: Lines of fusion and bead welds ....................................................... 36

Job 2: Pad weld - flat .............................................................................. 38

Job 3: Corner fillet weld - flat ................................................................... 40

Job 4: Corner fillet weld - horizontal/vertical .............................................. 42

Job 5: Lap fillet weld - flat ....................................................................... 44

Job 6: T-fillet weld - horizontal/vertical ..................................................... 46

Job 7: Butt weld - flat ............................................................................. 48

Project: Composite welded structure ......................................................... 50

Resource Evaluation Form ........................................................... 53

SAMPLE


© TAFE NSW (Training & Education Support, Industry Skills Unit Meadowbank) 2012 Page 15 of 56

Topic 1: Oxyacetylene welding safety Oxyacetylene 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 welding operator, oxyacetylene welding can injure others in the area where welding is taking place.

Safety hazards Typical safety hazards associated with this welding process include:

Burns

Burns caused by: � touching hot metal � hot torch parts, hot filler rods or sparks coming in contact with exposed skin � heat of the flame.

Burns from welding can cause discomfort and will often require first aid attention.

Weld fumes Fumes are given off from:

� metals being welded � oxides or surface coatings on metal parts being welded � cleaning solvents used on metal surfaces prior to welding.

Care should be taken when selecting surface cleaning agents. Manufacturer’s information should stipulate that the cleaning agent is safe to use in the presence of welding. 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.

Infra-red rays

The bright light emitted from the welding flame emits infra-red rays. These rays are dangerous and can cause permanent injury to eyes through long term unprotected exposure. Excessive exposure to the heat from the oxyacetylene flame can also cause fatigue to operators, especially when using large welding flames.

Compressed gases

Cylinders used for oxyacetylene welding contain gases stored at high pressures. It is important that they are handled, used and stored carefully according to the suppliers recommendations and instructions.

� Never USE OIL on any oxygen cylinders or fittings

SAMPLE


Page 16 of 56 © TAFE NSW (Training & Education Support, Industry Skills Unit Meadowbank) 2012

� Cylinders should be used and stored in the upright position at all times, and secured to avoid falling over

� Gases should not be used for any other purposes than that of welding � (See Hazards of Industrial Gases for more details).

Safety precautions

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

Use protective clothing and equipment (PPE) This includes:

� overalls or heavy drill cotton long trousers and long-sleeve shirt made from non-flammable material

� safety footwear with leather uppers and rubber soles � welders leather gloves/gauntlets � Australian standards approved welding goggles with correct filter lens shade

(e.g. Shade 5-6; 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 fire hazard. Lightweight clothing is not suitable for the intense heat emitted from fuel gas welding. New clothing should be washed to remove starching agents which have been known to be flammable. Old, worn clothing should be discarded as the garment may ignite due to general wear and tear and deterioration of the fibres. Never leave butane cigarette lighters in your pockets whilst welding as this can result in an explosion causing serious injury or death.

Oxyacetylene welding goggles

SAMPLE



Selection of filter lens

Shade of filter lens

Applications

5 General oxyacetylene welding, brazing, braze welding oxyacetylene welding cast iron and hard facing.

6 For welding pre-heated cast iron and thicker sections of material.

You should seek expert advice before selecting a filter lens shade lower than those listed above.

Welding screens

� In an open workshop or construction site, erect a welding screen made from non-reflective material. This will protect others nearby from the effects of stray welding sparks

� It is important to warn others working nearby that welding about to commence

� Safety glasses should be worn at all times by both the welding operator and others working nearby.

Portable screens make the workplace safer for other workers

SAMPLE



Hazards of industrial gases

Oxygen (O2)

Oxygen by itself is not flammable or explosive. However, it will support combustion and cause material to burn freely. Be extremely careful as it will form highly combustible and explosive mixtures. Oxygen must NEVER be used:

� to operate pneumatic tools � for spray painting � as a substitute for compressed air � to blow out pipelines, vessels or containers � to freshen the air or clear fumes in a confined space � to cool yourself or blow dust from clothing.

Acetylene (C2H2)

Acetylene is an industrial fuel gas. It produces a large amount of heat and in the oxyacetylene flame attains the highest flame temperature of any known mixture of combustible gases of about 3,100° C. The gas is dissolved in liquid acetone in the cylinder and full cylinder pressures are 1550 kPa. Safe use of acetylene gas includes;

� keeping cylinders upright � don’t transfer the gas from one cylinder to another � storing cylinders upright in a cool, well ventilated location.

Sparks emitted from the flame and weld pool

SAMPLE



Adequate ventilation Methods of ensuring that the air is safe to breathe are:

� natural ventilation: - Occurs in a workshop that has large doors and windows, the natural

movement of air will help reduce the concentration weld fumes � forced fume extraction:

- Often required if welding in a confined space or where there is little air movement a forced fume extraction system must be used

� respirators: - wear a standards-approved welding respirator when natural or forced

ventilation are not sufficient methods of reducing weld fume concentrations. Other methods of limiting exposure to fumes include:

� Keeping your head out of rising fumes from the weld area � Avoid breathing in fumes from metals such as stainless steel and nickel/nickel

alloys, and coated metal surfaces like galvanised steel � Using ventilation and respirators when welding these materials.

Care should be taken when selecting surface cleaning agents. Manufacturer’s information should stipulate that the cleaning agent is safe to use in the presence of welding.

Fume extractor providing safer work environment for welding operators

SAMPLE



Review questions The following questions have been included to help you revise what you have learnt in Topic 1: Oxyacetylene welding safety.

1. List three (3) safety hazards associated with the oxyacetylene welding process.

� ___________________________________________________________

� ___________________________________________________________

� ___________________________________________________________

2. Name four (4) items of protective equipment/clothing a welding operator should wear when oxyacetylene welding. � ___________________________________________________________

� ___________________________________________________________

� ___________________________________________________________

� ___________________________________________________________

3. State the recommended shade of filter lens for oxyacetylene welding.

_____________________________________________________________

4. List three (3) safety precautions that must be observed when handing and storing compressed gas cylinders. � ___________________________________________________________

� ___________________________________________________________

� ___________________________________________________________

5. List two (2) methods common used to ensure adequate ventilation is present to protect operators from welding fumes.

� ___________________________________________________________

� ___________________________________________________________

SAMPLE



6. State the name of the “bright light” emitted from the welding flame.

____________________________________________________

SAMPLE

MEM05004C Perform routine oxyacetylene welding … · Burns from welding can cause discomfort and...

Documents

Transcript of MEM05004C Perform routine oxyacetylene welding … · Burns from welding can cause discomfort and...