Manual Metal-Arc Welding - Low Carbon Steel — SEG Awards Vocationally-Related Qualification Design and Technology Revision

    This unit covers manual metal-arc (MMA) welding on low carbon steel, including safety, equipment, welding techniques, and defect identification. Learners m

    Topic Synopsis

    This unit covers manual metal-arc (MMA) welding on low carbon steel, including safety, equipment, welding techniques, and defect identification. Learners must demonstrate practical skills in producing welded joints and performing destructive tests.

    Key Concepts & Core Principles

    Exam Tips & Revision Strategies

    Common Misconceptions & Mistakes to Avoid

    Examiner Marking Points

    Manual Metal-Arc Welding - Low Carbon Steel

    SEG AWARDS
    vocational

    This unit covers manual metal-arc (MMA) welding on low carbon steel, including safety, equipment, welding techniques, and defect identification. Learners must demonstrate practical skills in producing welded joints and performing destructive tests.

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

    Assessment criteria

    SEG Awards Level 2 Award in Welding Techniques and Skills

    Topic Overview

    The SEG Awards Level 2 Award in Welding Techniques and Skills is a vocationally-related qualification that introduces students to the fundamental principles and practices of welding. This course covers essential welding processes, including Manual Metal Arc (MMA), Metal Inert Gas (MIG), and Tungsten Inert Gas (TIG) welding, with a strong emphasis on health and safety, joint preparation, and quality control. Students learn to interpret welding symbols, select appropriate equipment, and produce sound welds on various materials such as mild steel and aluminium.

    This qualification is crucial for students pursuing careers in engineering, construction, manufacturing, or automotive industries. It provides a solid foundation for further study in welding or related fields, such as fabrication or mechanical engineering. By mastering welding techniques, students develop practical skills that are highly valued in the workplace, including precision, problem-solving, and attention to detail. The course also aligns with industry standards, preparing students for certifications like those from the Welding Institute (TWI) or the American Welding Society (AWS).

    Within the wider Design and Technology curriculum, welding is a key manufacturing process that enables the creation of strong, durable structures and products. It complements other topics such as material properties, joining methods, and quality assurance. Understanding welding techniques enhances a student's ability to design and fabricate functional prototypes, making it an integral part of the engineering design process.

    Key Concepts

    Core ideas you must understand for this topic

    • →Welding processes: Understand the differences between MMA, MIG, and TIG welding, including their applications, advantages, and limitations. For example, MMA is versatile for outdoor use, MIG is fast for thin materials, and TIG produces high-quality welds on non-ferrous metals.
    • →Joint types and preparation: Know the five basic joint types (butt, lap, T, corner, and edge) and how to prepare edges by grinding, cleaning, and beveling to ensure proper penetration and strength.
    • →Welding parameters: Master the control of current, voltage, travel speed, and electrode angle. Incorrect settings can lead to defects like porosity, slag inclusion, or lack of fusion.
    • →Health and safety: Always wear appropriate PPE (welding helmet with correct shade, gloves, apron, and safety boots). Ensure adequate ventilation to avoid fume inhalation, and follow fire safety protocols, including having a fire extinguisher nearby.
    • →Quality control and inspection: Learn to identify common weld defects (e.g., undercut, overlap, spatter) and use non-destructive testing methods like visual inspection and dye penetrant testing to assess weld quality.

    Learning Objectives

    What you need to know and understand

    • 1.1 Identify the need to use appropriate PPE (personal protective equipment) when carrying out manual metal welding activities1.2 Identify associated risks when welding with MMA, to include:• arc radiation burns• arc eye• burns from handling hot materials• welding fumes• electric shocks • fire• sparks1.3 Identify fire prevention and emergency procedures required in the workplace, to include:• causes of fire• types of fire extinguisher used• evacuation procedures1.4 Identify the main groups of safety signs, to include:• warning• prohibition• mandatory• information signs1.5 Identify the function of the listed equipment when used with MMA welding activities:• transformer/generators• transformer/rectifiers• welding lead• welding return lead• welding earth• electrode holders1.6 Identify ancillary equipment used when welding with the MMA welding process1.7 Identify suitable storage conditions for manual metal welding electrodes1.8 Identify the electrode in terms of:• size by electrode diameter• flux coating type1.9 Identify appropriate safety checks on MMA welding equipment prior to use1.10 Prepare to carry out MMA welding to produce welded joints in the PA or PB positions, to include:• production of the correct welding preparation• identify distortion control methods to be used• select the correct electrode type/size• set the correct welding current• produce suitable tack welds• weld the joint• post weld cleaning1.11 Identify welding parameters to be used when completing welded joints using MMA welding, to include:• welding current• electrode slope and tilt angles• arc length• electrode polarity1.12 Identify suitable safety checks on welding equipment prior to use1.13 Complete a weld on:• low carbon steel greater than 6 mm in thickness or• stainless steel in materials greater than 3mm in thickness or • aluminium in materials greater than 3mm in thicknessusing the MMA welding process, to include as a minimum:• lap joint • open outside corner • single vee butt joint• tee fillet weldWelds to be completed in the PA or PB position1.14 Describe the limitations of visual inspection on completed welded joints using the MMA welding process1.15 Identify and describe typical welding defects that may be found in MMA welded joints, to include:• undercut • cracks• slag inclusions• porosity• arc craters• lack of penetration 1.16 Check completed welds for:• weld size to include leg length and throat thickness• weld profile• weld appearance and uniformity• absence of surface defects1.17 Complete the requirements for a report document on welds produced1.18 Prepare and carry out a destructive test on a fillet weld in accordance with the supplied drawing of the welded joint, to include:• nick break test1.19 Prepare and carry out destructive tests on a completed single vee butt weld in accordance with the supplied drawing of the welded joint, to include:• face bend test• root bend test• fracture test1.20 Identify appropriate documentation relating to welding activities, to include:• welding procedure specifications (WPS)• weld inspection report

    Assessment Criteria

    Key criteria assessors look for in your portfolio

    • Identify appropriate PPE and safety procedures for MMA welding.
    • Select correct electrodes and set welding parameters for low carbon steel.
    • Produce welded joints (lap, corner, butt, tee) in PA or PB positions.
    • Identify and describe common welding defects such as undercut and porosity.
    • Perform destructive tests (nick break, bend, fracture) and report results.

    Assessment Guidance

    Guidance for achieving higher grades

    • 💡Practise setting up the welding machine correctly.
    • 💡Learn the characteristics of each welding defect.
    • 💡Follow the WPS (Welding Procedure Specification) closely.
    • 💡Tip 1: In practical assessments, always set up your workstation correctly before starting. Examiners look for methodical preparation: check gas flow (for MIG/TIG), select correct electrode/wire, and adjust settings on a test piece. Rushing leads to mistakes.
    • 💡Tip 2: When answering theory questions, use technical terminology accurately. For example, distinguish between 'fusion' (melting base and filler) and 'penetration' (depth of fusion). Show understanding of how parameters affect weld bead shape.
    • 💡Tip 3: For written exams, practice interpreting welding symbols from BS EN ISO standards. Know how to identify weld type, size, length, and contour. A common question asks to sketch a symbol for a fillet weld with specific dimensions.

    Common Mistakes

    Common errors to avoid in your coursework

    • Incorrect electrode angle or arc length leading to poor weld quality.
    • Failing to clean the workpiece before welding.
    • Misidentifying defects due to lack of visual inspection practice.
    • Misconception: 'A longer arc length gives better penetration.' Correction: A long arc reduces penetration and increases spatter. Maintain a short arc length (about the diameter of the electrode) for stable arc and good fusion.
    • Misconception: 'MIG welding doesn't require cleaning the base metal.' Correction: Even MIG welding requires clean surfaces free from rust, oil, or paint to prevent porosity and ensure strong bonds. Always clean with a wire brush or grinder before welding.
    • Misconception: 'TIG welding is only for aluminium.' Correction: While TIG is excellent for aluminium, it is also used for stainless steel, copper, and thin sections of mild steel. It offers precise control but is slower than MIG.

    Frequently Asked Questions

    Common questions students ask about this topic

    Before You Start

    Prior knowledge that will help with this topic

    • •Basic understanding of material properties: Knowledge of how metals behave under heat (expansion, contraction, and melting points) helps in predicting weld distortion and selecting appropriate techniques.
    • •Health and safety fundamentals: Familiarity with workshop safety rules, including fire hazards, electrical safety, and proper use of PPE, is essential before handling welding equipment.
    • •Measurement and marking out: Ability to use rulers, squares, and scribers to accurately mark joint positions and ensure correct alignment before welding.

    Key Terminology

    Essential terms to know

    • 1.1 Identify the need to use appropriate PPE (personal protective equipment) when carrying out manual metal welding activities1.2 Identify associated risks when welding with MMA, to include:• arc radiation burns• arc eye• burns from handling hot materials• welding fumes• electric shocks • fire• sparks1.3 Identify fire prevention and emergency procedures required in the workplace, to include:• causes of fire• types of fire extinguisher used• evacuation procedures1.4 Identify the main groups of safety signs, to include:• warning• prohibition• mandatory• information signs1.5 Identify the function of the listed equipment when used with MMA welding activities:• transformer/generators• transformer/rectifiers• welding lead• welding return lead• welding earth• electrode holders1.6 Identify ancillary equipment used when welding with the MMA welding process1.7 Identify suitable storage conditions for manual metal welding electrodes1.8 Identify the electrode in terms of:• size by electrode diameter• flux coating type1.9 Identify appropriate safety checks on MMA welding equipment prior to use1.10 Prepare to carry out MMA welding to produce welded joints in the PA or PB positions, to include:• production of the correct welding preparation• identify distortion control methods to be used• select the correct electrode type/size• set the correct welding current• produce suitable tack welds• weld the joint• post weld cleaning1.11 Identify welding parameters to be used when completing welded joints using MMA welding, to include:• welding current• electrode slope and tilt angles• arc length• electrode polarity1.12 Identify suitable safety checks on welding equipment prior to use1.13 Complete a weld on:• low carbon steel greater than 6 mm in thickness or• stainless steel in materials greater than 3mm in thickness or • aluminium in materials greater than 3mm in thicknessusing the MMA welding process, to include as a minimum:• lap joint • open outside corner • single vee butt joint• tee fillet weldWelds to be completed in the PA or PB position1.14 Describe the limitations of visual inspection on completed welded joints using the MMA welding process1.15 Identify and describe typical welding defects that may be found in MMA welded joints, to include:• undercut • cracks• slag inclusions• porosity• arc craters• lack of penetration 1.16 Check completed welds for:• weld size to include leg length and throat thickness• weld profile• weld appearance and uniformity• absence of surface defects1.17 Complete the requirements for a report document on welds produced1.18 Prepare and carry out a destructive test on a fillet weld in accordance with the supplied drawing of the welded joint, to include:• nick break test1.19 Prepare and carry out destructive tests on a completed single vee butt weld in accordance with the supplied drawing of the welded joint, to include:• face bend test• root bend test• fracture test1.20 Identify appropriate documentation relating to welding activities, to include:• welding procedure specifications (WPS)• weld inspection report

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