Welder Interview Questions
& Model Answers, 2026

A Welding Procedure Specification is the written recipe: process, base and filler metal, joint design, position, amperage and voltage ranges, travel speed, preheat and interpass temperature, and any post-weld heat treatment. Say plainly that you weld to the WPS, not to habit. What stops you: no WPS on the job, parameters outside the qualified range, wrong filler or wrong preheat for the material. Asking is cheap; a rejected weld on a pressure joint is not.

For pipe: 1G is horizontal rolled (the pipe turns, you weld flat), 2G is vertical pipe welded horizontally, 5G is horizontal fixed (you weld around it, all positions), and 6G is fixed at 45 degrees, the hardest, since it combines flat, vertical and overhead in one pass. A 6G qualification is the one employers want because it generally qualifies you for all the positions below it. Plate uses 1F to 4F for fillets and 1G to 4G for grooves.

This is the question that separates welders who understand qualification from welders who just have a card. Your qualification is bounded by essential variables: the process (SMAW, GMAW, FCAW, GTAW), the position, the base metal group, the thickness and diameter range, the filler classification, and, for some codes, backing versus open root. Change an essential variable and you are outside your qualification. Also mention continuity: most codes require you to have used the process within the last six months or you requalify.

Porosity, gas trapped in the weld, from contamination, moisture, damp electrodes or lost shielding gas in the wind. Undercut, a groove at the toe, from excess current or travel speed and a bad angle. Lack of fusion and incomplete penetration, from low heat input, wrong root gap, or poor technique in the root. Cracking, hot cracks from chemistry and restraint, cold cracks from hydrogen (the answer is low-hydrogen electrodes kept in a rod oven, and preheat). Say what you check visually before an inspector does.

SMAW (stick) for field work, dirty or rusty material and wind, it is forgiving of conditions. GMAW (MIG) for clean shop steel and speed, but it is unforgiving of a breeze and of lack of fusion. FCAW for structural work with high deposition, self-shielded outdoors and gas-shielded in the shop. GTAW (TIG) where quality rules over speed: stainless, aluminium, thin wall and root passes on pipe. A strong answer ties each to a job you actually ran.

Hot work permit and a fire watch, combustibles removed or shielded to 35 feet, and the extinguisher present before the arc. In a confined space: permit, atmospheric testing before entry and continuously, forced ventilation or local exhaust for fume (manganese, hexavalent chromium on stainless), and an attendant outside with a way to get you out. Add the personal side, respirator where required, and the fact that you never leave a hot piece unmarked.

Own it with STAR and no defensiveness. What the rejection was (say, root lack of fusion on a 5G pipe coupon), how you found the cause with the inspector rather than arguing about it, how you cut it out, reprepped and rewelded to procedure, and what you changed in your root technique so it did not repeat. Interviewers know welds get rejected; they are testing whether you hide it.

This is a good question to have an answer to. A missing WPS, an unqualified procedure, material that was not what the print called for, a fit-up that would guarantee a bad root, or a confined space that had not been tested. Describe how you raised it (to the foreman or the inspector, calmly and with the reason), and what happened. Welders who will not put their stencil on bad work are the ones shops keep.

Sixty to ninety seconds: your years and your processes, your certifications and positions (for example AWS D1.1 3G and 4G, plus a 6G pipe qualification), the sectors you have worked (structural, fabrication, pipeline, pressure vessels), and what you want next. Get the position and code in the first fifteen seconds; that is the information they are waiting for.

Talk about process discipline rather than heroics: consistent fit-up and cleaning, machine settings written down and rechecked, electrodes kept properly (rod oven for low-hydrogen), and self-inspection of each pass rather than waiting for the QC round. Then the human part, on shutdown work, twelve-hour nights degrade everybody, so you slow down on the passes that matter and you speak up when you are too tired to hold a root.

Anchor to data and to your qualification: BLS OEWS May 2025 puts the welder median at $53,750/yr ($25.84/hr), with the top 10% above $77,530, and pipe, pressure and code work pays at the top of that. State an hourly range for your certifications and position, and ask what the shop's rate range is for a 6G-qualified welder versus a structural welder, the spread is real.

Ask for the whole number, not the base rate. On shutdowns and travel work the per diem, the overtime rules (over eight in a day or over forty in a week), double time on the seventh day, and who pays for travel days and lodging can be worth more than the hourly. Get it in writing, verbal per-diem promises on a shutdown are the most common pay dispute in this trade.

Take the test, but ask the rate question first and politely: 'Happy to test, what's the rate range for someone who passes at 6G?' A shop that will not give a range before a paid or unpaid test is telling you something. Also ask whether the test is paid, whether they supply consumables, and how quickly they call you with the result, a professional shop answers all three without hesitation.