Cert III Welding key terms

A ranked order of risk-reduction measures, from most to least reliable: eliminate the hazard, substitute it, engineer controls, apply administration, then use personal protective equipment as the last barrier.

The process of spotting anything in the workplace that could cause harm, such as fumes, hot slag, unguarded machinery or poor lighting, before work starts and as conditions change.

A structured judgement of how likely a hazard is to cause harm and how severe that harm would be, used to decide which controls are needed and whether work may proceed.

A written breakdown of a task into its steps, listing the hazards of each step and the controls that will be applied, usually reviewed with the crew before starting.

Clothing and gear worn to shield the body from welding hazards, including a filtered helmet, flame-resistant clothing, leather gloves, safety boots, hearing protection and respiratory protection where fumes require it.

Local exhaust ventilation, such as a fume arm or on-torch extraction, that captures airborne metal oxide and gas at the arc before the welder breathes it in confined or enclosed areas.

Work inside a tank, pit or vessel with restricted entry and poor natural ventilation, requiring an entry permit, atmospheric testing, a standby person and rescue arrangements before anyone enters.

A written authorisation to weld, cut or grind in an area where sparks or heat could start a fire, recording the fire watch, area clearance and precautions taken before work begins.

A designated person who stays in the work area during hot work and for a set period afterwards, watching for smouldering material and ready to raise the alarm or extinguish a fire.

Eye or skin injury caused by intense ultraviolet radiation from an arc, producing pain, redness and a gritty feeling, prevented by a properly shaded helmet and protective screens around the work.

A rating on the filter lens of a welding helmet that sets how much light and radiation it blocks, chosen to suit the process and current so the arc is visible without eye strain.

Lifting, carrying and positioning loads by hand, such as gas cylinders and steel sections, which must be planned to avoid back strain and to keep the body in a safe posture.

A drawing method that shows a three-dimensional object as separate flat views, typically front, top and side, arranged so each view represents what is seen looking squarely at that face.

A drawing convention where each view is placed on the side of the object it shows, so the top view sits above the front view and the right side view sits to its right.

The standard notation on a drawing that shows where a weld goes, using a reference line, arrow, fillet or groove shape and any size, length and spacing figures required.

The forked end of a welding reference line where process, procedure or specification notes are written, telling the fabricator which standard or procedure applies to that weld.

A thin line on a drawing terminated by arrowheads that carries a measurement figure, showing the size or position of a feature in the units stated on the drawing.

A drawing view that imagines the object cut open to reveal internal features, with the cut surface shown by hatching lines, used to show joint detail hidden in outside views.

The permitted amount by which a dimension may vary while still being acceptable, written as plus and minus limits or a range that the finished part must fall within.

A drawing or schedule that numbers each weld on a fabrication, linking every number to its size, type and inspection requirement so welders and inspectors can trace each joint.

A controlled document that states the approved variables for a joint, including process, consumable, current, voltage, travel speed and preheat, so the weld is made the same way each time.

The record of a test weld made to prove that a welding procedure produces sound results, listing the actual variables used and the results of mechanical and visual testing.

A welding supply whose output voltage changes widely with arc length while current stays close to the set value, characteristic of manual metal arc and tungsten arc welding.

A welding supply that holds voltage nearly steady while current rises and falls with arc length, giving the self-regulating behaviour used for gas metal arc welding with a wire feeder.

The percentage of a ten-minute period a power source can run at its rated output without overheating, so a 60 percent machine at 200 amps must rest or run cooler for the remaining time.

The gap between the electrode tip and the molten pool, which controls arc voltage and stability; too long gives spatter and poor penetration, too short risks sticking or stubbing.

The welding current in amps, which sets how much heat enters the joint and therefore controls penetration depth, deposition rate, bead width and the risk of burn-through.

The amount of energy delivered per unit length of weld, calculated from current, voltage and travel speed, which affects cooling rate, hardness and distortion in the finished joint.

A calculated value combining the carbon and alloy content of steel to estimate how readily it hardens and cracks when welded, guiding preheat and consumable choices.

Heating the base metal before welding to slow cooling, drive off moisture and reduce the risk of cracking in thick, high-carbon or low-temperature steels.

Delayed cracking in the heat-affected zone caused by hydrogen from moisture or contaminated consumables combined with hard microstructure and restraint, often appearing hours after welding.

Keeping consumables in dry, controlled conditions, with low-hydrogen electrodes held in heated ovens and issued in limited quantities, so moisture does not enter the weld.

Checking the classification marking on electrodes, wire and flux against the procedure before use, ensuring the correct strength, position capability and coating are being applied.

Shaping the edges of parts before welding by cutting, bevelling, cleaning and setting the root gap and land, so the arc can reach the full thickness and fuse both sides.

The small space left between the two members at the bottom of a joint, allowing the root pass to penetrate fully through the thickness without overlapping or missing fusion.

A short temporary weld used to hold parts in alignment until the main welds are made, sized and spaced so it does not crack or leave defects in the finished joint.

The first run deposited at the base of a joint, which must fuse into both side walls and give full penetration, since later passes cannot repair a defective root from the outside.

The angle of the electrode or torch relative to the joint as it moves along, which directs the arc force, controls bead shape and helps prevent slag being drawn into the weld.

Unwanted change in shape caused by uneven heating and cooling, managed by balanced sequences, backstep welding, clamping, pre-setting and keeping heat input under control.

A defect where the weld metal does not reach the full depth of the joint root, leaving a gap that concentrates stress and weakens the connection.

Trapped non-metallic material from electrode coatings or flux left inside the weld, usually from poor inter-run cleaning or incorrect travel angle, and detected by radiography or ultrasonics.

Rounded gas pockets trapped in solidified weld metal, caused by moisture, dirt, paint, wrong gas flow or excessive arc length, and visible as pinholes on the surface or on radiographs.

A groove melted into the base metal along the edge of a weld and left unfilled, reducing thickness and acting as a stress raiser, often from excessive current or poor travel angle.

Examination methods that reveal defects without damaging the weld, including visual inspection, dye penetrant, magnetic particle, ultrasonic and radiographic testing chosen to suit the joint.

The first and most basic quality check, examining bead profile, size, undercut, spatter and surface defects against the acceptance criteria before any other testing is arranged.

Testing that cuts or breaks a sample weld to reveal its internal quality, such as bend, tensile, nick-break and macro tests, used to qualify procedures and welder skill.

A planned list of routine checks and servicing for welders, cables, regulators and feeders, carried out at set intervals to keep equipment safe and prevent breakdowns mid-job.

Checking welding leads and return cables for cuts, exposed conductors, damaged insulation and loose lugs before use, replacing anything that could shock the operator or arc badly.

Tagging out and recording a faulty machine, torch or regulator so it cannot be used until repaired, following the site procedure and informing the supervisor promptly.

Keeping cylinders upright, secured, away from heat and separated by gas type in a ventilated area, with caps fitted and fuel and oxygen bottles kept apart.

A short briefing before work begins where the crew reviews the task, hazards, controls and responsibilities, giving everyone a chance to raise concerns before welding starts.

A brief, focused discussion held on site about a specific safety or quality topic, used to refresh knowledge and share lessons from recent incidents or inspection findings.

The principle that everyone in the supply chain, from designer to supervisor to welder, shares accountability for safety and quality, so problems must be raised rather than passed on.