Glossary
The welding glossary
68 terms in plain language — defined once, linked everywhere they appear across the site.
duty cycle The fraction of each 10-minute period a welder can run at a … stick-out The distance from the MIG contact tip to the work — 8–10 mm … penetration How deep the weld fuses into the parent metal below the surf… shielding gas The gas (argon, argon-CO2 mix, CO2) flowing over the weld po… flux core Hollow MIG-style wire with flux inside that generates its ow… slag The hardened flux crust over a stick or flux-core weld, chip… polarity Which way current flows: electrode positive (heat in the wir… arc length The gap between electrode and work. Stick wants about one ro… travel speed How fast you move along the joint — with current, the other … weld pool The molten puddle under the arc. Learning to read it (width,… tungsten The non-consumable TIG electrode. 2% lanthanated (blue) is t… filler rod The hand-fed metal rod added to a TIG pool (or the wire in M… weave Side-to-side torch/rod motion on wider joints or in vertical… backstep Welding backwards along the joint sequence to pull distortio… tack weld Small temporary welds holding fit-up before the full seam. T… butt weld A joint between two pieces in the same plane. Often bevelled… fillet weld A triangular weld joining two surfaces at right angles — the… throat The effective thickness of a fillet weld through its cross-s… root pass The first pass in a multi-pass weld, at the bottom of the jo… cap The final visible pass of a multi-pass weld. Cosmetic matter… hot pass The second pass after the root — typically run hot and fast … undercut A groove melted into the parent metal at the weld toe, leavi… porosity Gas bubbles trapped in the weld — the classic shielding fail… spatter Metal droplets thrown from the arc onto surrounding steel. V… crater The dimple left when an arc stops abruptly mid-pool. Unfille… distortion Warpage from uneven heating across a joint. Control with tac… heat input The energy per length of weld (joules per millimetre) — the … haz Heat-Affected Zone — the band of parent metal next to the we… sugaring Oxidation of stainless steel's weld root from lack of back-s… purging Flooding the back of a joint with argon during stainless/alu… gas lens A TIG torch component with mesh screens that laminises gas f… lift arc A TIG start method: touch tungsten to work, lift, arc strike… hf start High-Frequency start — TIG arc ignition without touching, vi… ac balance On AC TIG (aluminium), the ratio of electrode-negative to el… short circuit transfer MIG mode at low voltage where the wire dips into the pool — … spray transfer MIG mode above ~200 A where droplets spray across the arc — … synergic Machine mode where one knob sets everything: voltage and wir… pulse mig MIG with a pulsed current — drops transfer at controlled pea… inverter Modern welder power source: switching electronics instead of… igbt The switching transistor technology inside modern inverter w… ocv Open-Circuit Voltage — the voltage at the torch before the a… ampere (amps) The current measurement that governs penetration and heat. T… voltage The setting that governs arc length and bead width in MIG — … wire feed speed How fast MIG wire feeds, in metres per minute — with voltage… deposition rate Kilograms of filler deposited per arc-hour — the productivit… argon The inert shielding gas for TIG everything, MIG aluminium/st… co2 Carbon dioxide — cheap MIG gas for thick steel: deep penetra… argon mix Argon-CO2 blend (92/8 standard in Australia) for MIG steel —… gasless wire Self-shielded flux-cored MIG wire — no bottle, wind-proof. T… electrode Generic term for the current-carrying end: stick rods, MIG w… e7018 / e48xx Low-hydrogen stick rod classes (US/AU naming) for structural… 6013 The general-purpose rutile stick rod — easy arc, forgiving, … er70s-6 The standard mild-steel MIG wire class — 70 ksi tensile with… er308l / er316l Stainless filler matched to 304 and 316 grades respectively … er4043 / er5356 The two aluminium fillers: 4043 flows beautifully (general),… mill scale The blue-grey oxide skin on hot-rolled steel. Welding throug… galvanising Zinc anti-corrosion coating on steel. Weldable, but zinc fum… cast iron High-carbon iron that cracks if welded hot-and-fast. Nickel … chromoly 4130 chromium-molybdenum alloy steel — motorsport and airfra… as 1796 The Australian standard governing pressure-welder certificat… as/nzs 1554 The joint Australian/New Zealand structural steel welding st… 6g The hardest welding test position: pipe fixed at 45°, coveri… welding ticket Australian slang for an AS 1796 certification — proof you te… arc eye Photokeratitis — sunburn of the cornea from arc exposure. Gr… metal fume fever Flu-like zinc oxide poisoning from welding galvanised steel … pape Powered Air-Purifying Respirator — a helmet-integrated fan a… rmd tip Replaceable copper MIG contact tip that transfers current to… liner The conduit guiding MIG wire from drive rolls to torch. Kink…