MEM05047B Weld using flux cored arc welding process

Transcription

1 MEM05 Metal and Engineering Training Package MEM05047B Weld using flux cored arc welding process Learner guide Version 2 Training and Education Support Industry Skills Unit Meadowbank Product Code: 5804

2 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 resource package: CIGWELD ESAB Lincoln Electric Australia Standards Australia Welding Industries of Australia Writer: Updated from existing TAFE resources. Reviewers: Ed Harkness (Illawara Institute) Stephen Davies (TES Industry Skills Unit) TAFE NSW Project Manager: Stephen Davies Education Programs Manager Training and Education Support, Industry Skills Unit, Meadowbank 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: Fax: TAFE NSW (Training and Education Support, Industry Skills Unit Meadowbank) 2013 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. ISBN TAFE NSW (Training & Education Support Industry Skills Unit, Meadowbank) 2013

3 Contents Introduction General introduction Using this learner guide Prior knowledge and experience Unit of competency overview...9 Topic 1: FCAW safety Review questions Topic 2: Basic electrical terms and definitions Review questions Topic 3: The flux cored arc welding process (FCAW) Review questions Topic 4: FCAW consumables Review questions Topic 5: Weld defects and machine faults Review questions Topic 6: Distortion control and weld joints Review questions Practical work JOB 1: T-Fillet - Horizontal/vertical (Plate) JOB 2: Corner fillet - Horizontal/vertical (Plate) JOB 3: T-fillet - Vertical (Plate) JOB 4: Corner fillet - Vertical (Plate) JOB 5: T-Fillet - Overhead (Plate) JOB 6: Fillet - Overhead (Pipe to plate) JOB 7: Butt weld - Flat (Plate) JOB 8: Butt weld - 1G Pipe (Rotated) JOB 9: Butt weld - Horizontal (Plate) Job 10: Butt weld - Horizontal/vertical (Single bevel) Job 11: Butt weld - Vertical (Single bevel) Resource Evaluation Form TAFE NSW (Training & Education Support Industry Skills Unit, Meadowbank) 2013

4 Topic 1: FCAW safety The Work, Health and Safety Act 2011 (WHS Act) and WHS Regulations are enforced throughout all States and Territories. This legislation is aimed at providing consistency, certainty and clarity across Australia making it easy to understand workplace health and safety responsibilities. Consequently this act and its regulations requires employers, employees, contractors and visitors on a worksite to take every reasonable step to work safely and responsibly in the workplace. There are no short cuts to working safely, its everyone s responsibility to either eliminate and minimise potential risks in the workplace, report faulty equipment, unsafe environments and comply with WHS policies and procedures. Detailed information relating to the WHS Act and regulations can be found on: WorkCover Authority of NSW website; or on Safe Work Australia; Note: WorkCover NSW is the regulator for NSW and have the authority to monitor and enforce WHS laws and regulations within the state of NSW. WORK SAFE HOME SAFE Operators must understand and apply the principles governing welding safety, equipment used and workplace health and safety precautions required. The following workplace risks need to be clearly understood and applied when working in a welding environment. Welding hazards Working with electrical equipment, exposure to arc radiation, welding fumes hot metal and sparks are all hazards associated with FCAW. These hazards are explained below and advice is given on how to minimise these risks to yourself and others in the workplace. Electric shocks (low voltage) Electric shocks are possible on the secondary (low voltage) side of the welding circuit. Typical causes are a result of: Working on wet or damp floors Working in a very humid climate or rainy/wet weather. Electic shocks can be avoided by: Standing on insulated mats or wooden boards Wearing dry leather gloves, cloths and wearing rubber soled shoes Ensuring internal electrical repairs to power sources or wire feed units is done by a qualified electrician Regularly inspecting power plugs, leads and guns to ensure they are safe and properly insulted. If faulty, tag and replace immediately. TAFE NSW (TES, Industry Skills Unit Meadowbank) 2013 Page 15 of 98

5 Harmful rays Harmful rays given off form the FCAW process include: Ultra violet rays (UV) Infra-red rays (IR) Excessive brightness. These rays can damage and burn the skin. Ray burn is similar to severe sunburn; your skin reddens and then peels. If ray burn is severe, blisters and sores will develop. Arc rays can also harm a persons eyes causing a condition called a flash or welders flash which is like having your eyes full of sand. The severity of injury due to welders flash is greater with the FCAW process due to the high current ranges used. The symptoms of a flash are delayed pain, reddening and soreness to the eyes which may require medical treatment. Operators must wear appropriate clothing, gloves and PPE to avoid exposure to arc rays. Screening and appropriate signage should be erected or located around the welding area to further reduce the dangers of a flash occurring to others working nearby. Other workers should also wear safety glasses and protective clothing to further reduce the risk. Due to the intersity of arc rays given off from the FCAW process it may be necessary to fit a slightly darker filter lens into your welding helmet. Depending upon the currect levels used, it may be necessary to increase shading from 10 to a shade 11 or even 12. It is important that filter lens are approved and identified in accordance with Australian Standards. For detailed information refer to AS/NZS Portable welding screens Page 16 of 98 TAFE NSW (TES, Industry Skills Unit Meadowbank) 2013

6 Welding fumes Gases, dusts and vapours are given off during FCAW welding. Due to its nature, the FCAW process has a tendency to produce much higher fume levels than other arc welding processes. The volume of fume produced is influenced by the type and size of wire and current levels used. Self-shielding FCAW wires generally produce much higher fume levels than GMAW solid wires. Inhaling welding fume can result in: Asphyxiation due to depletion of oxygen in the work area. This presents a problem when working in confined spaces A build-up of poisonous metals in the body, such as lead, cadmium, zinc Respiratory ailments from a wheeziness to serious lung disorders. Sources of fume can arise from: The production of oxides and nitrous gases from heating of the atmosphere Carbon dioxide from the decomposition of fluxes Incomplete combustion or oxidation of nitrogen from the atmosphere Surface coatings on steel such as; -- Galvanising -- Cadmium plating -- Chrome plating -- Paints and solvents such as red oxide, rust inhibitors, coated parts and degreasing agents Elements contained in the metal being welded. It is important to use some form of fume extraction when using FCAW to prevent inhalation. Different types of extraction systems are available for different working conditions such as working on site, in a confined space or in an open workshop. Fumes can be removed by using one of the following. Fume extraction guns are used in a workshop environment when using lower fume level wires Welding helmets with an attached air supply unit can be used for workshop or on site application where high fume levels are anticipated especially in confined spaces Portable fume extractors can be positioned close to the fume source and moved as required Flexible fume extractors are ideal for use in confined spaces or welding in tanks or containers Fume extraction tables whereby fumes are removed through a ducting system. FCAW fume gun TAFE NSW (TES, Industry Skills Unit Meadowbank) 2013 Page 17 of 98

7 Flexible extraction unit Hot metal Molten droplets have a way of getting into footwear when arc welding. This can be avoided by wearing personal protective equipment (PPE), clothing and footwear. When welding out of position, for example in the vertical or overhead, wear spats over your boots and under the legs of your overalls for added protection. PPE Operators using the FCAW process must wear approved personal protective equipment and safety clothing. Examples include: Welding helmet Leather gloves or gauntlets Heavy drill overalls Steel capped boots with leather uppers and rubber soles Safety glasses Leather apron Leather jacket (if required) Leather spats (if required). Operator wearing PPE and clothing Page 18 of 98 TAFE NSW (TES, Industry Skills Unit Meadowbank) 2013

8 Review questions These questions have been included to help you revise what you have learnt in Topic 1: FCAW safety. 1. List three (3) precautions operators must take to avoid an electric shock. 2. List five (5) items of clothing and PPE that must be worn to minimise FCAW risks. 3. Other than electric shock, list two (2) hazards associated with working in a welding environment. 4. Name two (2) harmful arc rays emitted from the FCAW process. 5. Briefly explain the harmful effects the above arc rays can have on the welding operator. TAFE NSW (TES, Industry Skills Unit Meadowbank) 2013 Page 19 of 98

9 Multiple choice questions (Tick the box with the correct answer) 6. Welding over galvanised steel will produce: Rust resistant welds Stronger welds Poisonous fumes High tensile welds 7. A welding filter lens must be: Shade 5 minimum Approved and identified to Australian Standards Made in Australia Green 8. Ensuring a safe working environment is the responsibility of the: Employer and employee Welding supervisor Owner of the business Chief engineer 9. Legislation governing the safety of Australians in the workplace is covered in: The Work Health and Safety act of 2011 AS 1796 certification of welding operators and supervisors The NSW OHS act of 2000 The Metal and Engineering Award True/False questions (Circle the correct response) 10. WorkCover NSW have the authority to monitor and enforce WHS laws and regulations in NSW. True False 11. FCAW process produces lower fume levels than other arc welding processes. True False Page 20 of 98 TAFE NSW (TES, Industry Skills Unit Meadowbank) 2013