Job Knowledge
Cutting and gougingHealth, safety and accident prevention
Standards and classifications
Weldability and joining of materials
Welding defects and distortion
Welding equipment
Welding processes - arc
Welding processes - others
Mechanical testing
Job knowledge 8:
Thermal gouging (May 1995)
The principles of thermal gouging are outlined including the cutting processes that can be used, materials suitable for gouging, applications and safety.
Job knowledge 9:
Oxygen-fuel gas flame gouging (Jun. 1995)
The principles of flame gouging are outlined including process characteristics, operating parameters and techniques.
Job knowledge 10:
Manual metal arc gouging (Jul. 1995)
The principles of MMA gouging are outlined including process characteristics, electrodes, power sources, operating parameters and applications.
Job knowledge 11:
Plasma arc gouging (Sep. 1995)
The principles of plasma arc gouging are outlined including process characteristics, powers sources, electrodes, plasma and cooling gases, and operating techniques.
Job knowledge 12:
Air carbon arc gouging (Oct. 1995)
The principles of air carbon arc gouging are outlined including applications, electrodes, power sources, air supply, problems of carbon pick-up, operating parameters and process techniques.
Job knowledge 49:
Oxyfuel cutting - process and fuel gases. (September 2000)
The oxyfuel cutting process is introduced. Characteristics of the common fuel gases - acetylene, propane, MAPP (methylacetylene-propadiene), propylene and natural gas - are presented.
Job knowledge 50:
Cutting processes - application of oxyfuel cutting (November 2000)
Includes advantages of the process, the choice of fuel gas and nozzle design to maximise performance, and best practice to ensure adequate quality of the cut surface.
Job knowledge 51:
Cutting processes - plasma arc cutting - process and equipment considerations
The plasma cutting process is described covering process characteristics, power source, cut edge quality and process variants (dual gas, water injection, water shroud, air plasma, high tolerance plasma)
Job knowledge 52:
Cutting processes - laser cutting (March 2001)
Describes the suitability of common materials for laser cutting; process advantages; relationship between lens properties and cut thickness; comparison of the characteristics of flying optics, fixed optics and hybrid systems; and
problems of reflection when cutting aluminium
Job knowledge 53:
Laser cutting: process variants. (May 2001)
CO
2 and Nd:YAG laser cutting are discussed. Topics include process characteristics, assist gases, cut quality and process economics.
Job knowledge 26:
Health, safety and accident prevention - General (Apr.1997)
The general hazards which may arise when carrying out welding and related operations, are identified.
Job knowledge 27:
Health, safety and accident prevention - oxyacetylene welding, cutting and heating
Guidelines are given on the principal health and safety considerations for oxyacetylene welding to ensure safe welding practices.
Job knowledge 28:
Health, safety and accident prevention: electrical hazards - power source and installation
Article gives the principal health and safety considerations to ensure safe welding practices and prevent accidents, particularly on power source installation and electrical hazards
Job knowledge 29:
Health, safety and accident prevention - arc welding (Jul.97)
This article gives guidelines on health and safety considerations when arc welding to ensure safe practice and prevent accidents. The principal hazards are associated with electric shock and arc radiation.
Job knowledge 30:
Health, safety and accident prevention - health risks of welding fume/gases
The principal health and safety considerations are looked at to ensure safe welding practices. A general overview of the hazards associated with fume and gases generated during welding.
Job knowledge 31:
Health, safety and accident prevention - health risks from fume and gases during welding (Oct.97)
Factors affecting welding fume composition for gas, MMA, FCA, MIG/MAG, TIG, plasma and submerged arc processes.
Job knowledge 32:
Health, safety and accident prevention - control of welding fume
Factors that affect welder's exposure to fume are summarised. The measures and equipment used to control welding fume and gases are described.
Job knowledge 1:
Welding and joining process classification (Oct. 1994)
Process terminology according to European standard, EN 24063:1992 is explained and factors which must be taken into account when choosing a suitable welding or joining process are discussed.
Job knowledge 38:
Standards - application standards, codes of practice and quality levels (Nov.1998)
The requirements for standards on welding procedure and welder approval are explained together with the quality levels for imperfections.
Job knowledge 39:
Standards - Approval of welding procedures, welder and welding operators (Jan.1999)
The alternative routes for welding procedure approval are described together with the requirements for welder or welding operator approval.
Job knowledge 64:
A review of the application of weld symbols on drawings - Part 1 (May 2003)
Introduces weld symbols according to BS EN 22553
Job knowledge 65:
A review of the application of weld symbols on drawings - Part 2 (July 2003)
Presents example of symbols used on weld drawings to indicate the location, type, size etc of welds required, welding process to use, and so on.
Job knowledge 66:
Fillet welded joints - a review of the practicalities. (September 2003)
Looks at common joint designs and features and discusses everyday practical problems of achieving correct weld size and shape. Spotlights differences between designers' intentions and what can happen on the shop floor, and
reviews inspection issues.
Job knowledge 19:
Weldability of materials - carbon manganese and low alloy steels. (Aug.1996)
Guidance is given on ferritic steel weldability and the causes of weld imperfections: porosity, solidification cracking, hydrogen cracking and reheat cracking. Procedure and welder techniques for reducing the risk of these in arc
welding are recommended.
Job knowledge 20:
Weldability of materials - stainless steel. (Sept. 1996)
Weldability is discussed for austenitic, ferritic, martensitic and duplex stainless steels, with emphasis on the avoidance of weld imperfections
Job knowledge 21:
Weldability of materials - Aluminium alloys. (Oct. 1996)
Characteristics of aluminium alloys are discussed with emphasis on their fusion weldability. Suitable filler metal grades are listed. Causes and avoidance of porosity, solidification cracking, liquation cracking and poor weld
shape are described.
Job knowledge 22:
Weldability of materials - Nickel and nickel alloys. (Nov. 1996)
Weldability is discussed of nickel and Ni solid solution and precipitation hardening alloys, with causes and avoidance of porosity, oxide inclusions, lack of inter-run fusion, solidification cracks, microfissures, PWHT cracks and
stress corrosion cracks.
Job knowledge 23:
Weldability of materials - Copper and copper alloys. (Jan.1997)
Weldability of copper and Cu alloys (including brasses, bronzes and cupronickels )is discussed with emphasis on fusion welding and avoidance of weld imperfections. Recommended filler materials are listed.
Job knowledge 24:
Weldability of materials - Titanium and titanium alloys. (Feb. 1997)
Types of titanium and Ti alloys are described with emphasis on causes and avoidance of weld imperfections: porosity, embrittlement and contamination cracking. Suitable filler metals are listed.
Job knowledge 25:
Weldability of materials - cast irons (March 1997)
Welding of various types of cast iron by oxy-fuel, MMA, MIG and FCA welding processes is discussed with emphasis on weldability.
Job knowledge 54:
Ceramics - materials, joining and applications (July 2001)
The characteristics of ceramics as engineering materials, industrial applications and factors affecting selection of joining processes are described.
Job knowledge 33:
Distortion - types and causes
Covers several key issues on distortion in arc welded fabrications, especially causes of distortion, basic types of welding distortion and factors affecting the degree of distortion
Job knowledge 34:
Distortion - prevention by design
The article concentrates on providing information on the application of best practice principles to limit distortion during the design and fabrication of arc welded structures.
Job knowledge 35:
Distortion - prevention by pre-setting, pre-bending or use of restraint
Focuses on distortion prevention through pre-setting and pre-bending parts or use of restraint. Provides illustrated, practical information on applying techniques and includes best practice guidelines.
Job knowledge 36:
Distortion - prevention by fabrication techniques
Means of reducing and controlling weld distortion are described, covering control of distortion by tack welding, back-to-back assembly and stiffening and selection of welding process, technique and sequence.
Job knowledge 37:
Distortion - corrective techniques
General guidelines are provided on 'best practice' for correcting distortion using mechanical or thermal techniques.
Job knowledge 40:
Weld defects/imperfections - incomplete root fusion or penetration (Mar.1999)
Types of weld imperfections are introduced and the nature, causes, avoidance and repair of lack of penetration at the weld root when arc welding are described. Acceptance standards to ISO 5817 are mentioned.
Job knowledge 41:
Weld defects/imperfections in welds - lack of sidewall and inter-run fusion (May 1999)
The characteristic features and principal causes of lack of sidewall and inter-run fusion are described. General guidelines on best practice are given so that welders can minimise the risk of imperfections during fabrication.
Job knowledge 42:
Defects/imperfections in welds - porosity (July 1999)
The characteristic features and principal causes of porosity imperfections are described. Best practice guidelines are given so welders can minimise porosity risk during fabrication.
Job knowledge 43:
Defects/imperfections in welds - slag inclusions (September 1999)
The characteristic features and principal causes of slag imperfections are described.
Job knowledge 44:
Defects - solidification cracking. (November 1999)
Covers identification; causes in structural and stainless steels and in aluminium alloys; avoidance; acceptance standards; detection and remedial action for solidification cracking in welds.
Job knowledge 45:
Defects/hydrogen cracks in steels - identification. (January 2000)
Describes the characteristic features and principal causes of hydrogen cracks in ferritic steels.
Job knowledge 46:
Defects - hydrogen cracks in steels - prevention and best practice. (March 2000)
Methods of reducing the risk of hydrogen cracking when arc welding steels are described.
Job knowledge 47:
Defects - lamellar tearing. (May 2000)
The characteristic features, principal causes and best practice in minimising the risk of lamellar tearing are described.
Job knowledge 48:
Defects/imperfections in welds - reheat cracking (July 2000)
The characteristic features and principal causes of reheat cracking are described. General guidelines on best practice are given so that welders can minimise the risk of reheat cracking in welded fabrications.
Job knowledge 67:
A general review of geometric shape imperfections - types and causes - part 1. (November 2003)
Looks at those imperfections related to poor geometric shape, particularly excess weld metal (reinforcement), undercut, overlap (cold lapping), linear misalignment, and incompletely filled groove. Causes, acceptability and
avoidance are covered.
Job knowledge 68:
A general review of the causes and acceptance of shape imperfections - Part 2 (January 2004)
Covers causes, avoidance and acceptance criteria for imperfections in butt and fillet weld bead shape: excess penetration, root concavity, excess convexity, oversize and undersize fillets (large or small throat), asymmetric
fillet, and poor fit-up
Job knowledge 13:
Equipment for oxyacetylene welding (Dec. 1995)
Gas welding torch, hoses, gas regulators and flame traps are described. Differences between oxygen and acetylene cylinders are listed. Typical gas pressures and flow rates for work on C-Mn steels are given. Safety checks are
indicated.
Job knowledge 14:
Equipment for manual metal arc (MMA or SMA) welding (Jan. 1996)
The power source, electrode holder, cables, protective clothing and fume extraction equipment required for safe MMA welding are described. Care of covered electrodes is described, including storage and drying.
Job knowledge 15:
Equipment for MIG welding (Feb. 1996)
The power source, wire feed system, conduit, gun and protective equipment for MIG/MAG welding are described. Current and voltage settings for dip and spray transfer mode and recommended welding glass shade numbers are
presented.
Job knowledge 16:
Equipment for submerged arc welding. (Apr.1996)
The power sources and welding guns suitable for submerged arc welding are described, including manual and mechanised (single and twin wire) operation. Stickout lengths, gun angle, flux handling and protective equipment are
covered.
Job knowledge 17:
Equipment for tungsten inert gas (TIG, GTA) welding (May 1996)
Power sources, torches, backing systems and protective clothing for TIG welding are described.
Job knowledge 18:
Equipment for plasma welding. (Jan. 1996)
Equipment is described for microplasma, medium current plasma and keyhole plasma welding including power source, torch, nozzle, electrode, plasma and shielding gases, backing systems and protective equipment. Recommended shade
numbers are given.
Job knowledge 2:
The manual metal arc process (Nov. 1994)
Principles of the MMA (SMA) welding method are outlined including characteristics of the types of electrodes and electrode coatings, suitable power sources and current ranges.
Job knowledge 4:
Solid wire MIG welding (Jan. 1995)
The principles of MIG/MAG welding are outlined including process characteristics, metal transfer modes, shielding gas types and process applications.
Job knowledge 5:
Submerged arc welding process (Feb. 1995)
The principles of the submerged arc welding process are outlined including process features and characteristics, process variants (e.g. multiple wire), flux types and applications.
Job knowledge 6:
Tungsten inert gas (TIG or GTA) welding (Mar. 1995)
The principles of TIG welding are outlined including process characteristics, power sources, arc starting, electrodes, shielding gases and applications.
Job knowledge 7:
Plasma welding (Apr. 1995)
The principles of plasma welding are outlined including process characteristics, operating modes, power sources, arc starting, electrodes, plasma and shielding gases and applications.
Job knowledge 3:
The oxyacetylene welding [gas welding] process (Oct. 1994)
The principles of the oxyfuel gas welding process are presented including flame types, equipment, operating characteristics and techniques.
Job knowledge 57:
Extrusion welding of thermoplastics (March 2002)
Equipment, procedures and applications for extrusion welding are described.
Job knowledge 55:
Welding techniques for thermoplastics (September 2001)
An overview of the variety of techniques available to industry for the thermal joining of thermoplastic is presented, covering methods based on friction, heated tool, hot gas, energy beam and electromagnetic effects.
Job knowledge 56:
Hot gas welding of plastics: Part 1 - the basics (November 2001)
Describes the hot gas welding process, welding equipment and welding parameters, materials that can be hot gas welded and welder certification.
Job knowledge 56b:
Hot gas welding of plastics: Part 2 - welding techniques (January 2002)
The hot gas welding process is described covering material preparation, joint preparations, procedures for round nozzle welding and speed welding, weld shape and finishing.
Job knowledge 58:
Butt fusion welding of plastics (May 2002)
Butt fusion welding of plastic pipes is described concisely, including tips for a successful weld, machine set up, aligning and clamping the pipe, preparing the pipe, noting heating and cooling times and fusion pressures,
welding, cooling and inspection.
Job knowledge 59:
Friction welding of plastics
Processes suitable for joining thermoplastics are described: linear friction welding (vibration welding), rotational friction welding (spin welding), orbital welding, angular friction welding. Procedure, process parameters,
component design and joint preparation are covered.
Job knowledge 60:
Hot plate welding of plastics moulded components (September 2002)
The hot plate welding process is described in some detail, covering joint design, welding equipment, procedures and welding conditions.
Job knowledge 61:
Ultrasonic welding of injection moulded components - Part 1 - Process and equipment
The equipment used for ultrasonic welding of plastic components is described
Job knowledge 62:
Ultrasonic welding of injection moulded components - Part 2. Component design and weld parameters. (January 2003)
Discusses joint preparation for projection and shear joints, other aspects of component design for weldability, and selection of amplitude and welding mode.
Job knowledge 69:
Mechanical testing - Tensile testing Part 1 (March 2004)
Tensile testing is described, covering test specimen form, determination of the engineering stress/strain curve, and derivation of test results: ultimate tensile strength, yield point, elongation, reduction in area, Young's
modulus of elasticity and proof stress.
Job knowledge 70:
Mechanical testing - Tensile testing Part 2 (May 2004)
To approve a butt welding procedure most specifications such as BS EN 288 Parts 3 and 4 and ASME IX require tensile tests to be carried out.
Job knowledge 71:
Mechanical testing - notched bar or impact testing (July 2004)
The Charpy-V test for characterising notch toughness is described. The qualitative nature of the test, outline procedures and test analysis are described.
Job knowledge 72:
Notched bar or impact testing. Part II (September 2004)
An overview of impact testing of welds and some of the factors which affect the transition temperature, such as composition and microstructure. Part 2 of a technical article on the principles and practice of impact testing.
Copyright © 2005, The Welding Institute