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

    Tungsten-arc gas shielded welding (TAG) of stainless steel in the overhead position requires knowledge of safety, equipment, parameters, and distortion con

    Topic Synopsis

    Tungsten-arc gas shielded welding (TAG) of stainless steel in the overhead position requires knowledge of safety, equipment, parameters, and distortion control. This Level 3 unit covers theory and practical skills.

    Key Concepts & Core Principles

    Exam Tips & Revision Strategies

    Common Misconceptions & Mistakes to Avoid

    Examiner Marking Points

    Tungsten-Arc Gas Shielded Welding - (Overhead) - Stainless Steel

    SEG AWARDS
    vocational

    Tungsten-arc gas shielded welding (TAG) of stainless steel in the overhead position requires knowledge of safety, equipment, parameters, and distortion control. This Level 3 unit covers theory and practical skills.

    1
    Learning Outcomes
    3
    Assessment Guidance
    3
    Key Skills
    1
    Key Terms
    4
    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 aiming to become proficient welders in the engineering and manufacturing sectors. This diploma covers a wide range of welding processes, including Manual Metal Arc (MMA), Metal Inert Gas (MIG), and Tungsten Inert Gas (TIG) welding, as well as advanced techniques such as pipe welding and welding in different positions. Students develop practical skills in preparing materials, setting up equipment, and producing high-quality welds that meet industry standards, alongside theoretical knowledge of welding metallurgy, safety procedures, and quality control.

    This qualification is essential for those seeking careers as welding technicians, fabricators, or maintenance engineers, as it provides the hands-on experience and certification required by employers. The diploma also integrates key aspects of design and technology, such as interpreting engineering drawings, selecting appropriate welding processes for specific materials, and understanding the mechanical properties of welded joints. By completing this diploma, students gain a comprehensive foundation that prepares them for further study or direct entry into the welding industry.

    Within the wider context of Design and Technology, welding is a critical fabrication technique that bridges design concepts with practical implementation. The Level 3 Diploma emphasizes precision, safety, and problem-solving, enabling students to contribute to projects ranging from structural steelwork to automotive components. Mastery of welding techniques not only enhances employability but also fosters an understanding of material science and engineering principles, making it a valuable component of vocational education.

    Key Concepts

    Core ideas you must understand for this topic

    • →Welding processes: Understand the principles, advantages, and limitations of MMA, MIG, and TIG welding, including appropriate applications for each process.
    • →Welding positions: Master flat, horizontal, vertical, and overhead welding positions, as each requires different techniques and affects weld quality.
    • →Weld defects and inspection: Identify common defects like porosity, slag inclusion, and undercut, and learn non-destructive testing methods such as visual inspection and dye penetrant testing.
    • →Material preparation: Properly clean, bevel, and fit materials to ensure strong, defect-free welds, including understanding heat-affected zones and preheating requirements.
    • →Safety and regulations: Adhere to health and safety standards, including proper use of PPE, ventilation, and fire prevention, as well as compliance with British and European welding standards.

    Learning Objectives

    What you need to know and understand

    • 1.1. Identify the roles of various organisations involved with Health and safety in the workplace, to include:• Health and Safety Executive (HSE)• Environmental Health• Local Authorities1.2. Identify the roles of various individuals involved with Health and Safety in the workplace, to include:• Company safety officers• Company safety representatives• Environmental health officers• HSE inspectors1.3. Identify the purpose and typical contents of an organisations Health and Safety Policy1.4. Describe the purpose of a risk assessment, to include:• who should carry out risk assessments• when to carry out a risk assessment• identification of the 5 steps of risk assessment1.5. Identify the precautions to be taken when working in high risk areas, to include:• risk assessments• permits to work• high/low temperature working conditions• lock off systems• isolation of equipment1.6. Describe the control and safe removal of welding fumes and gases created during the welding process, to include:• natural extraction• local extraction• PPE and specialist breathing equipment1.7. Describe the hazards associated when using the TAG welding process, to include:• arc radiation• using high frequency• production of phosgene gas1.8. Identify the power sources used in TAG welding1.9. Identify the type of welding current (AC/DC) and polarity to be used when welding:• low carbon steel• stainless steel• aluminium1.10. Describe the application and use of equipment used in the TAG welding process, to include:• high frequency unit• current control foot pedal• gas pressure regulator• gas flow meter• gas lens1.11. Describe the importance of correct storage conditions for tungsten electrodes and filler wires, to include:• location• ventilation• contamination• labelling 1.12. Identify the range of different alloying elements added to tungsten electrodes1.13. Identify the electrode (tip) preparation required when using an AC or DC welding current1.14. Identify the content and application of a range of filler wires used in the TAG welding process1.15. Describe the effects of using damaged tungsten electrodes and filler wires1.16. Identify the range and application of shielding gases used in the TAG welding process1.17. Identify and select the welding parameters to be used when welding low carbon steel, stainless steel or aluminium in the overhead welding position (PE), to include:• welding voltage• slope in/slope out control• torch slope and tilt angles• high frequency• speed of travel• pre/post gas flow• shielding gas flow rate (LPM)1.18. Describe the application and function of gas backing /purging1.19. Identify suitable welding preparations for the type of joint and material thickness being welded, to include:• included angle• angle of bevel• root face dimension• root gap dimension1.20. Describe the advantages and limitations of the methods listed that are used to produce suitable welding preparations on materials, to include:• thermal methods• mechanical (chip forming)• shearing• bevelling machines• abrasive methods1.21. Identify the main types of distortion found in completed welded joints, to include:• longitudinal• transverse• angular1.22. Identify the main causes of distortion in welded joints1.23. Identify methods used to control distortion in welded joints1.24. Describe the significance of residual stress found in welded joints1.25. Identify appropriate safety checks on the welding equipment prior to use1.26. Select suitable welding parameters to enable the listed joints to be welded by the TAG welding process on one material type to cover, low carbon steel, stainless steel or aluminium in a thickness range of between 1.6 mm to 3 mm.• tee fillet (PE)• butt (PE)• open outside corner (PE)• lap joint (PE)1.27. Carry out destructive tests on the completed welds and document the results. Tests to include:• face bend• root bend• fracture test• nick break test1.28. Identify the function of:• weld inspection activities• quality control• quality assurance1.29. Des

    Assessment Criteria

    Key criteria assessors look for in your portfolio

    • Identify health and safety roles and risk assessment steps.
    • Describe TAG welding equipment, shielding gases, and electrodes.
    • Select correct parameters for overhead stainless steel welding.
    • Control distortion and perform destructive tests.

    Assessment Guidance

    Guidance for achieving higher grades

    • 💡Memorise safety regulations and risk assessment steps.
    • 💡Practice setting parameters for different materials.
    • 💡Understand distortion causes and control methods.
    • 💡Pay close attention to weld preparation and cleanliness. Examiners often deduct marks for poor fit-up or contamination, so ensure edges are clean and properly aligned before welding.
    • 💡Demonstrate your understanding of welding parameters by explaining why you chose specific current, voltage, and travel speed for each joint. This shows depth of knowledge beyond just performing the weld.
    • 💡Practice welding in all positions, especially vertical and overhead, as these are commonly tested and require refined technique. Use consistent travel speed and angle to produce uniform beads.

    Common Mistakes

    Common errors to avoid in your coursework

    • Using incorrect electrode preparation for AC/DC.
    • Inadequate gas shielding leading to porosity.
    • Poor joint preparation causing lack of fusion.
    • Misconception: MIG welding is always easier than TIG welding. Correction: While MIG welding is more forgiving for beginners, TIG welding offers greater control and is essential for thin materials or critical joints. Both require practice to master.
    • 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 compromise strength. Always conduct proper inspection and testing.
    • Misconception: Welding is just about joining metal. Correction: Welding involves understanding metallurgy, heat control, distortion management, and adherence to codes. It is a skilled trade requiring theoretical knowledge and practical precision.

    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 and their properties, such as carbon steel, stainless steel, and aluminium.
    • •Familiarity with workshop safety practices and the use of hand tools and measuring equipment.
    • •Completion of a Level 2 welding qualification or equivalent experience in basic welding techniques.

    Key Terminology

    Essential terms to know

    • 1.1. Identify the roles of various organisations involved with Health and safety in the workplace, to include:• Health and Safety Executive (HSE)• Environmental Health• Local Authorities1.2. Identify the roles of various individuals involved with Health and Safety in the workplace, to include:• Company safety officers• Company safety representatives• Environmental health officers• HSE inspectors1.3. Identify the purpose and typical contents of an organisations Health and Safety Policy1.4. Describe the purpose of a risk assessment, to include:• who should carry out risk assessments• when to carry out a risk assessment• identification of the 5 steps of risk assessment1.5. Identify the precautions to be taken when working in high risk areas, to include:• risk assessments• permits to work• high/low temperature working conditions• lock off systems• isolation of equipment1.6. Describe the control and safe removal of welding fumes and gases created during the welding process, to include:• natural extraction• local extraction• PPE and specialist breathing equipment1.7. Describe the hazards associated when using the TAG welding process, to include:• arc radiation• using high frequency• production of phosgene gas1.8. Identify the power sources used in TAG welding1.9. Identify the type of welding current (AC/DC) and polarity to be used when welding:• low carbon steel• stainless steel• aluminium1.10. Describe the application and use of equipment used in the TAG welding process, to include:• high frequency unit• current control foot pedal• gas pressure regulator• gas flow meter• gas lens1.11. Describe the importance of correct storage conditions for tungsten electrodes and filler wires, to include:• location• ventilation• contamination• labelling 1.12. Identify the range of different alloying elements added to tungsten electrodes1.13. Identify the electrode (tip) preparation required when using an AC or DC welding current1.14. Identify the content and application of a range of filler wires used in the TAG welding process1.15. Describe the effects of using damaged tungsten electrodes and filler wires1.16. Identify the range and application of shielding gases used in the TAG welding process1.17. Identify and select the welding parameters to be used when welding low carbon steel, stainless steel or aluminium in the overhead welding position (PE), to include:• welding voltage• slope in/slope out control• torch slope and tilt angles• high frequency• speed of travel• pre/post gas flow• shielding gas flow rate (LPM)1.18. Describe the application and function of gas backing /purging1.19. Identify suitable welding preparations for the type of joint and material thickness being welded, to include:• included angle• angle of bevel• root face dimension• root gap dimension1.20. Describe the advantages and limitations of the methods listed that are used to produce suitable welding preparations on materials, to include:• thermal methods• mechanical (chip forming)• shearing• bevelling machines• abrasive methods1.21. Identify the main types of distortion found in completed welded joints, to include:• longitudinal• transverse• angular1.22. Identify the main causes of distortion in welded joints1.23. Identify methods used to control distortion in welded joints1.24. Describe the significance of residual stress found in welded joints1.25. Identify appropriate safety checks on the welding equipment prior to use1.26. Select suitable welding parameters to enable the listed joints to be welded by the TAG welding process on one material type to cover, low carbon steel, stainless steel or aluminium in a thickness range of between 1.6 mm to 3 mm.• tee fillet (PE)• butt (PE)• open outside corner (PE)• lap joint (PE)1.27. Carry out destructive tests on the completed welds and document the results. Tests to include:• face bend• root bend• fracture test• nick break test1.28. Identify the function of:• weld inspection activities• quality control• quality assurance1.29. Des

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