Cert III Welding flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hierarchy of control

The ranked order of hazard controls from most to least effective: elimination, substitution, engineering controls, administrative controls, and finally personal protective equipment as the last line of defence.

Hot work fire watch

A person assigned to monitor for fire during hot work and for at least 30-60 minutes after completion, with combustibles within about 10-11 m removed, shielded or wetted.

Confined space atmosphere limits

Entry requires oxygen between 19.5% and 23.5%, flammable gas below 5% of the lower explosive limit, contaminants below exposure standards, continuous ventilation, a standby person and a rescue plan.

Filter shade selection

The lens darkness number chosen for the process and current: about shade 9-11 for arc welding at 100-200 A and shade 5-6 for oxy-fuel gas welding, increasing with amperage.

Third-angle projection

A drawing convention where each view is placed on the near side of the object, so the top view appears above the front view and the right-side view appears to the right.

Fillet weld symbol dimensions

On a weld symbol the size (leg length) is written to the left of the symbol, while the weld length and pitch of intermittent welds are written to the right.

Weld all around symbol

A small circle placed at the junction of the arrow line and reference line, indicating that the weld is to be made continuously around the entire joint perimeter.

Drawing scale 1:10

A ratio meaning one unit measured on the drawing represents ten units on the actual part, so a 35 mm scaled dimension corresponds to 350 mm actual size.

Constant-current power source

A welding supply that holds current nearly constant as arc length changes, used for manual metal arc and gas tungsten arc welding, where the welder controls arc length.

Constant-voltage power source

A welding supply that holds voltage nearly constant, used for gas metal arc welding, where wire feed speed sets the current and voltage setting controls arc length.

Duty cycle meaning

The percentage of a ten-minute period a machine can operate at a rated current; 60% at 250 A means six minutes welding and four minutes cooling in every ten.

AC for aluminium GTAW

Alternating current is used because the positive half-cycle breaks up the refractory aluminium oxide layer while the negative half-cycle provides penetration and cools the tungsten electrode.

Carbon equivalent formula

CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15, used to estimate weldability; values above about 0.40-0.45% indicate that preheat is needed.

Low-hydrogen electrode storage

Basic coated electrodes such as the E7018 class must be kept dry in a heated holding oven at about 100-150 C and baked according to the manufacturer's instructions before use.

Aluminium oxide melting point

Aluminium oxide melts near 2050 C while the aluminium beneath melts near 660 C, so the oxide must be removed mechanically or by AC cleaning action before welding.

Single-V butt joint preparation

A typical preparation uses a 60-75 degree included bevel angle with a 1.5-3 mm root gap and a 1.5-2 mm root face to control penetration and burn-through.

Drag versus push angle

A drag or backhand travel angle of 5-15 degrees gives good penetration for most flat and horizontal work, while a push angle improves visibility but reduces penetration.

Fillet weld work angle

For a T-joint fillet weld the electrode is held at about 45 degrees to each plate so that heat and filler are distributed evenly and both legs fuse equally.

Backstep welding technique

A distortion-control method in which each bead starts behind the previous bead and progresses toward the free end, spreading heat input and reducing pulling and distortion.

Vertical-up versus vertical-down

Vertical-up welding gives deeper penetration and better fusion and is used for structural joints, while vertical-down is faster but shallow and suits only thin sheet.

Fillet weld throat thickness

The throat is the shortest distance from the weld root to the face; for a 90-degree fillet it equals the leg length multiplied by 0.707.

Dye penetrant testing

A non-destructive method that draws penetrant out of surface-breaking defects on non-porous materials, revealing cracks, laps and porosity as visible indications.

Magnetic particle testing

A non-destructive method using magnetic flux and iron particles to reveal surface and near-surface defects in ferromagnetic steel; it cannot be used on austenitic stainless steel.

Hydrogen-assisted cold cracking

Cracking that appears hours to days after welding in thick or high-strength steel, caused by hydrogen, restraint and hard microstructure, and prevented by low-hydrogen consumables and preheat.

WPS and PQR relationship

A welding procedure specification states the qualified variables for production, while the procedure qualification record documents the destructive test results that prove the procedure is sound.

Bird-nesting wire feed fault

A tangle of wire at the drive rolls usually caused by excessive roll tension, an incorrectly sized groove, a blocked or kinked liner, or a worn contact tip.

GMAW gas flow rate

Shielding gas flow is typically 10-15 litres per minute; too low allows air ingress and porosity, while too high causes turbulence that also draws in air.

Erratic arc troubleshooting

An unstable arc is commonly caused by a poor earth return connection, loose cable or connector, incorrect polarity, damaged electrode or unsuitable power source settings.

Thermal overload trips

Repeated overload trips indicate the machine is being run beyond its duty cycle or that cooling fans and vents are blocked and need cleaning.

Non-conformance report process

Defective work is tagged or segregated, the defect and location are recorded, and the site non-conformance process is followed before authorised rework and re-inspection.

AS/NZS 1554 scope

The Australian and New Zealand standard for structural steel welding, covering materials, qualification, workmanship and acceptance criteria for structural joints.

Weld records and traceability

Keeping welder qualification certificates, consumable batch records and inspection reports allows any defect to be traced back to a welder, procedure or batch of consumables.