Tungsten-Arc Gas Shielded Welding - (Vertical) - Stainless steel — SEG Awards Vocationally-Related Qualification Design and Technology Revision

    This unit covers TAG welding of stainless steel in the vertical position, including health and safety, equipment, parameters, and defect identification. Le

    Topic Synopsis

    This unit covers TAG welding of stainless steel in the vertical position, including health and safety, equipment, parameters, and defect identification. Learners must follow WPS and perform visual and destructive tests.

    Key Concepts & Core Principles

    Exam Tips & Revision Strategies

    Common Misconceptions & Mistakes to Avoid

    Examiner Marking Points

    Tungsten-Arc Gas Shielded Welding - (Vertical) - Stainless steel

    SEG AWARDS
    vocational

    This unit covers TAG welding of stainless steel in the vertical position, including health and safety, equipment, parameters, and defect identification. Learners must follow WPS and perform visual and destructive tests.

    1
    Learning Outcomes
    3
    Assessment Guidance
    3
    Key Skills
    1
    Key Terms
    5
    Assessment Criteria

    Assessment criteria

    SEG Awards Level 3 Diploma in Welding Techniques and Skills

    Topic Overview

    The SEG Awards Level 3 Diploma in Welding Techniques and Skills is a vocationally-related qualification designed for students who wish to pursue a career in welding and fabrication. This diploma covers a wide range of welding processes, including Manual Metal Arc (MMA), Metal Inert Gas (MIG), Tungsten Inert Gas (TIG), and oxy-acetylene welding. Students develop practical skills in preparing, setting up, and executing welds on various materials such as carbon steel, stainless steel, and aluminium. The course also emphasises health and safety regulations, quality control, and interpretation of engineering drawings, ensuring that learners are industry-ready.

    This qualification is part of the Design and Technology curriculum and is equivalent to A-levels, providing UCAS points for university entry or direct progression into apprenticeships and employment. It is assessed through a combination of practical assessments and written exams, testing both hands-on competence and theoretical knowledge. By mastering welding techniques, students gain a valuable trade skill that is in high demand across sectors like construction, manufacturing, automotive, and aerospace.

    The diploma is structured to build from basic principles to advanced techniques. Early units focus on health and safety, welding equipment, and basic joint configurations. Later units delve into complex welding positions, defect identification, and non-destructive testing methods. This progression ensures that students not only learn how to weld but also understand the science behind the processes, enabling them to troubleshoot and produce high-quality welds consistently.

    Key Concepts

    Core ideas you must understand for this topic

    • →Welding Processes: Understand the principles, advantages, and limitations of MMA, MIG, TIG, and oxy-acetylene welding, including appropriate applications for each.
    • →Joint Configurations and Positions: Master the five basic joint types (butt, lap, T, corner, edge) and welding positions (flat, horizontal, vertical, overhead) as per BS EN ISO standards.
    • →Weld Defects and Quality Control: Identify common defects like porosity, slag inclusion, undercut, and lack of fusion; understand causes and prevention methods.
    • →Health and Safety: Comply with COSHH regulations, use personal protective equipment (PPE), and follow safe working practices for welding fumes, fire, and electrical hazards.
    • →Material Properties and Preparation: Know how carbon steel, stainless steel, and aluminium behave under heat; prepare edges by grinding, cleaning, and beveling to ensure sound welds.

    Learning Objectives

    What you need to know and understand

    • 1.1. Identify the responsibilities of both the employer and the employee when complying with the Health and Safety at Work Act 19741.2. Identify the use of current legislation, to include:• COSHH (Control of Substances Hazardous to Health)• PUWER (Provision and Use of Work Equipment)• RIDDOR (Reporting of Injuries, Diseases, and Dangerous Occurrences Regulations)1.3. Identify the use of a risk assessment procedure1.4. Identify safe working practices when using the TAG welding process, to include working:• in a confined space• at an height above 2 metres • with containers that have held chemicals or flammable liquids • in damp or wet conditions• with hazards from using high frequency units1.5. Describe the function of the equipment used in the TAG welding process, to include:• rectifier• inverter• high frequency units• welding lead cable and clamp• welding return cable and clamp• secondary earth and connector• torch• tungsten• collet• shroud• cooling system• gas supply, regulator and flow meter1.6. Identify suitable maintenance checks that would be required on the items listed in 2.11.7. State the procedures to be followed for the safe storage of welding equipment when the welding activity has been completed1.8. Identify a range of tungsten electrodes that are used for the TAG welding process, to include:• types used• size (diameter)• alloying additions• preparation of electrode tip (shape/dimensions)1.9. Identify a range of filler wires that are used for the TAG welding process, to include:• types used• size (diameter)• alloying additions1.10. Describe the effects of incorrect storage of tungsten electrode and filler wires1.11. State the effect of using damaged tungsten electrode and filler wires when carrying out welding activities1.12. Identify the shielding gas/es used in TAG welding1.13. Identify the function of the shielding gas used in TAG welding1.14. Identify and select the welding parameters to be used when welding in the vertical welding position (PF/PG):• welding current• torch slope and tilt angles• filler wire slope and tilt angles• shielding gas flow rate• arc length• speed of travel1.15. Identify the use of autogenous techniques when using the TAG welding process1.16. Identify suitable welding preparations for the type of joint and material thickness being welded1.17. Identify terms associated with welding preparations, to include:• included angle• angle of bevel• root face dimension• root gap dimension 1.18. Describe the application of distortion control techniques, to include: • pre-setting • restraint• joint geometry • chills• weld sequence1.19. Be able to follow instructions given on a WPS (Welding Procedure Sheet)1.20. Identify appropriate safety checks on the welding equipment prior to use1.21. Select suitable welding parameters to enable the listed joints to be welded by the TAG welding process on low carbon steel or stainless steel or aluminium• tee fillet (PF)• butt (PF)• open outside corner (PF or PG)• lap joint (PF or PG)1.22. Carry out visual inspection of completed welds1.23. Prepare and carry out nick break tests on completed fillet welds1.24. Prepare and carry out destructive tests on completed butt welds, to include:• face bend • root bend• fracture test 1.25. Record the results of the weld examination as detailed in 7.1, 7.2 and 7.31.26. Identify and describe typical defects found in the TAG welding process joints, to include:• cracks• inclusions• undercut• lack of fusion• arc craters• porosity• lack of penetration1.27. Identify possible causes of the defects listed in 8.1

    Assessment Criteria

    Key criteria assessors look for in your portfolio

    • Identifies health and safety responsibilities and legislation.
    • Describes TAG welding equipment and its function.
    • Selects correct welding parameters for vertical welding.
    • Performs welds on specified joints and carries out tests.
    • Identifies welding defects and their causes.

    Assessment Guidance

    Guidance for achieving higher grades

    • 💡Memorise key parameters for vertical welding.
    • 💡Practice setting up equipment safely.
    • 💡Learn common defects and their remedies.
    • 💡In practical assessments, always perform a pre-weld check of equipment and materials. Examiners award marks for methodical preparation, including correct gas flow rates, wire feed speed, and electrode selection.
    • 💡When answering theory questions, use specific terminology from the syllabus, such as 'dilution', 'heat input', and 'interpass temperature'. Refer to relevant standards (e.g., BS EN 287-1 for welder approval) to demonstrate depth of knowledge.
    • 💡For written exams, practice sketching weld symbols from BS EN ISO 2553. Accurate interpretation of symbols is a common area where students lose marks. Label all parts clearly.

    Common Mistakes

    Common errors to avoid in your coursework

    • Incorrect tungsten preparation leading to arc instability.
    • Poor gas shielding causing porosity.
    • Incorrect travel speed or angle causing lack of fusion.
    • Misconception: MIG welding is always easier than TIG. Correction: While MIG is more forgiving on cleanliness, TIG offers greater control and is preferred for thin materials and aesthetic welds. Each process has its own challenges.
    • Misconception: A visually appealing weld is always a strong weld. Correction: Appearance does not guarantee integrity. Internal defects like lack of fusion or porosity can weaken a weld. Non-destructive testing (e.g., dye penetrant) is essential for critical applications.
    • Misconception: More heat always means better penetration. Correction: Excessive heat can cause burn-through, distortion, and weakened heat-affected zones. Correct amperage and travel speed are crucial for optimal penetration without defects.

    Frequently Asked Questions

    Common questions students ask about this topic

    Before You Start

    Prior knowledge that will help with this topic

    • •Basic understanding of engineering materials (e.g., properties of metals) from Level 2 study or GCSE Design and Technology.
    • •Familiarity with workshop health and safety practices, including use of PPE and fire safety.
    • •Competence in reading simple engineering drawings and understanding dimensions and tolerances.

    Key Terminology

    Essential terms to know

    • 1.1. Identify the responsibilities of both the employer and the employee when complying with the Health and Safety at Work Act 19741.2. Identify the use of current legislation, to include:• COSHH (Control of Substances Hazardous to Health)• PUWER (Provision and Use of Work Equipment)• RIDDOR (Reporting of Injuries, Diseases, and Dangerous Occurrences Regulations)1.3. Identify the use of a risk assessment procedure1.4. Identify safe working practices when using the TAG welding process, to include working:• in a confined space• at an height above 2 metres • with containers that have held chemicals or flammable liquids • in damp or wet conditions• with hazards from using high frequency units1.5. Describe the function of the equipment used in the TAG welding process, to include:• rectifier• inverter• high frequency units• welding lead cable and clamp• welding return cable and clamp• secondary earth and connector• torch• tungsten• collet• shroud• cooling system• gas supply, regulator and flow meter1.6. Identify suitable maintenance checks that would be required on the items listed in 2.11.7. State the procedures to be followed for the safe storage of welding equipment when the welding activity has been completed1.8. Identify a range of tungsten electrodes that are used for the TAG welding process, to include:• types used• size (diameter)• alloying additions• preparation of electrode tip (shape/dimensions)1.9. Identify a range of filler wires that are used for the TAG welding process, to include:• types used• size (diameter)• alloying additions1.10. Describe the effects of incorrect storage of tungsten electrode and filler wires1.11. State the effect of using damaged tungsten electrode and filler wires when carrying out welding activities1.12. Identify the shielding gas/es used in TAG welding1.13. Identify the function of the shielding gas used in TAG welding1.14. Identify and select the welding parameters to be used when welding in the vertical welding position (PF/PG):• welding current• torch slope and tilt angles• filler wire slope and tilt angles• shielding gas flow rate• arc length• speed of travel1.15. Identify the use of autogenous techniques when using the TAG welding process1.16. Identify suitable welding preparations for the type of joint and material thickness being welded1.17. Identify terms associated with welding preparations, to include:• included angle• angle of bevel• root face dimension• root gap dimension 1.18. Describe the application of distortion control techniques, to include: • pre-setting • restraint• joint geometry • chills• weld sequence1.19. Be able to follow instructions given on a WPS (Welding Procedure Sheet)1.20. Identify appropriate safety checks on the welding equipment prior to use1.21. Select suitable welding parameters to enable the listed joints to be welded by the TAG welding process on low carbon steel or stainless steel or aluminium• tee fillet (PF)• butt (PF)• open outside corner (PF or PG)• lap joint (PF or PG)1.22. Carry out visual inspection of completed welds1.23. Prepare and carry out nick break tests on completed fillet welds1.24. Prepare and carry out destructive tests on completed butt welds, to include:• face bend • root bend• fracture test 1.25. Record the results of the weld examination as detailed in 7.1, 7.2 and 7.31.26. Identify and describe typical defects found in the TAG welding process joints, to include:• cracks• inclusions• undercut• lack of fusion• arc craters• porosity• lack of penetration1.27. Identify possible causes of the defects listed in 8.1

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