Welder interview questions and answers
Welder interviews test what you can actually weld and how you check your work. Expect questions on processes, positions, reading drawings and fixing defects, and usually a practical weld test.
The most common question in the videos we reviewed: What safety steps do you take before and during welding.
Which questions come up most?
We read the transcripts of the 5 most watched interview videos for this job and counted how many of them say each question gets asked. The table shows the top ones. The answers below are ours, written to show the shape of a strong reply.
| Question | Videos that mention it (of 5) |
|---|---|
| What safety steps do you take before and during welding? | 4 |
| Which welding processes have you worked with? | 3 |
| What are the main types of welded joints? | 2 |
| What welding positions do you know, and which are you tested in? | 2 |
| What common weld defects do you know and how do you avoid them? | 2 |
| How do you check the quality of your welds? | 2 |
| How do you decide current and other settings for a job? | 2 |
| Tell me about a hard welding job and how you handled it. | 2 |
| Tell me about a mistake you made and what you did about it. | 2 |
| What is preheating and why is it done? | 1 |
The questions, with strong answers
What safety steps do you take before and during welding?
What they check: Whether you protect yourself and others and check the area, the gear and the equipment before striking an arc.
A strong answer: Before welding I check the area for flammable material and ventilation, wear flame resistant clothing, a proper helmet, gloves, boots and eye protection, and inspect the machine, cables and gas hoses. During welding I keep the work area clear, use fume extraction when needed, warn people nearby, and never leave hot work unattended. After welding I let metal cool and check for smouldering.
A weak answer: Saying you just put on a helmet and gloves. It ignores fire risk, fumes, and equipment checks, so it sounds careless.
Which welding processes have you worked with?
What they check: Whether your hands on experience matches the job: which process, which metals and what position.
A strong answer: Name each process you really used, such as MIG, TIG, stick and flux core, and say which metals and thicknesses you did with each. For example, TIG for thin stainless and root passes, stick for structural work outdoors, MIG for fast shop fabrication. Be honest about what you have done less often. Mention any test you passed, so they can match you to the work.
A weak answer: Naming every process you have heard of. Interviewers often follow up with detail, and a thin answer is quickly found out.
What are the main types of welded joints?
What they check: Whether you know the basic vocabulary used on drawings and in shop talk.
A strong answer: The common joints are butt, lap, tee, corner and edge. Name each in simple terms: butt joins two pieces end to end in one plane, lap overlaps them, tee has one piece standing on another, corner meets at an angle and edge joins the edges of parallel plates. Add which joint you used most, and what weld type, such as groove or fillet, fits each.
A weak answer: Naming only one or two joints. It shows narrow experience and makes drawings hard to read.
What welding positions do you know, and which are you tested in?
What they check: Whether you can weld out of position, and understand how pipe and plate test positions are labelled.
A strong answer: Four basic positions: flat, horizontal, vertical and overhead. In test codes these appear as 1G flat, 2G horizontal, 3G vertical and 4G overhead on plate, with pipe positions such as 5G fixed horizontal and 6G fixed at an angle. Say which you have passed, the process, and whether uphill or downhill. Fixed pipe positions are harder because the angle changes as you go around.
A weak answer: Saying you can weld in any position without naming one. Interviewers want proof, usually a test or certificate.
What common weld defects do you know and how do you avoid them?
What they check: Whether you can recognise bad welds and fix the cause rather than just grind them away.
A strong answer: Common defects are porosity, spatter, undercut, overlap, lack of fusion and incomplete penetration. Causes include dirty metal, damp rods, wrong gas flow, too long an arc, wrong current or travel speed. Prevent them by cleaning the joint, drying electrodes, setting parameters for the job, keeping a steady arc length, and checking fit up. Make a test weld when something changes.
A weak answer: Naming defects but not the causes. It suggests you only repair them, and will repeat the problem.
How do you check the quality of your welds?
What they check: Whether you care about quality and know visual checks and common non-destructive tests.
A strong answer: Start before welding with clean metal, good fit up and the right settings. Then inspect each pass visually for size, profile, cracks, undercut and porosity. For critical work, tests such as dye penetrant, magnetic particle, radiography or ultrasound are done by qualified people, and you follow the written procedure. Fix problems straight away, and record what you did.
How do you decide current and other settings for a job?
What they check: Whether you understand how electrode size, material thickness and process affect heat and quality.
A strong answer: Check the welding procedure first if there is one. Otherwise set by electrode or wire size, material thickness, joint type and position. Thicker metal and bigger rods need more current. Out of position welding needs less. Use the maker's chart as a start, run a test piece, and adjust. For stick, polarity depends on the electrode type, so check the box.
Tell me about a hard welding job and how you handled it.
What they check: Whether you solve problems calmly with planning, the right tools and teamwork.
A strong answer: Pick one real job, such as thin material, a tight space, or a deadline. Say what made it hard, what you changed, for example lower heat, smaller filler, back purge, or a jig to hold the part, and the result. Mention talking to the supervisor or team early. End with what you learned and how the weld passed inspection.
Tell me about a mistake you made and what you did about it.
What they check: Whether you are honest, report errors quickly and change your habits.
A strong answer: Choose a real, small mistake, like a cut or bracket made to the wrong angle. Say what happened, that you found it by checking, and that you told your supervisor right away. Explain how you fixed it, for example by making a new part to the drawing. Finish with the habit you added, such as measuring twice with a square or protractor before welding.
What is preheating and why is it done?
What they check: Whether you understand how heat and cooling rate affect weld cracking.
A strong answer: Preheating warms the metal before welding. It slows cooling and drives off moisture, which lowers the chance of cracks, especially on thick or high carbon steel. The temperature comes from the procedure or material specification and is checked with a temperature stick or gauge. Keep the interpass temperature within limits, and cool slowly if the procedure says so.
What is the colour code and safe handling for gas cylinders?
What they check: Whether you handle cylinders safely and can name gases correctly, since colours differ by country.
A strong answer: Cylinder colours depend on local rules, so read the label and gas name instead of trusting colour alone. Keep cylinders upright and chained, caps on when moving, away from heat and from oil, and store oxygen apart from fuel gas. Check hoses, regulators and flashback arrestors, and test joints for leaks with soapy water, never with a flame.
How do you read a weld procedure or a welder test certificate?
What they check: Whether you can follow written instructions and know what your qualification covers.
A strong answer: A procedure tells you the process, material, thickness, filler, current range, polarity, preheat and joint prep. A welder test certificate shows your name, date, process, material, thickness, position and filler you were tested on. Say plainly what yours covers, and that you will only weld within it. Ask for the procedure before starting any code job.
How do you troubleshoot welding equipment problems?
What they check: Whether you can find simple faults in the machine, wire feeder or gas supply instead of waiting for others.
A strong answer: Work through it in order. Check power, ground clamp, cables and connections. Then consumables, such as tip, liner, drive rolls and tension, and the gas flow and hoses. Change one thing at a time and run a test weld. Poor feeding or a bad ground is the usual cause of an unstable arc. If it is a machine fault, tag it out and report it.
Tell me about a time you worked to a tight deadline.
What they check: Whether you stay safe and keep quality when time is short.
A strong answer: Describe a real job with a short deadline. Explain how you planned the order of work, prepared and fitted parts ahead, split tasks with teammates and kept talking with the supervisor. Make clear that you did not skip inspection or safety to save time. Close with the result, such as on time delivery and no rework.
What to know about the hiring process
- Many welder hiring processes include a practical weld test, often on plate or pipe, before or instead of a long interview.
- Employers ask which processes, metals and positions you have been qualified in, and may ask to see test certificates.
- Safety questions about protective gear, fire, fumes and gas cylinders appear in almost every interview.
- Some interviews ask short quiz style questions on defects, joints, polarity and electrodes.
Practise these out loud
On Just One Interview, you type the role and the skills you want tested, and an AI interviewer asks you the questions out loud. You get a report with a score for each answer and a count of your filler words. It runs in the browser on your phone, and the free plan includes 20 minutes of practice a month.