Just my opinion, nothing more. I'm a CWI who teaches Welding and Inspection. Folks ask me questions through the AWS-CWI Seminars I teach. I do my best to give them an answer that educates.
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Saturday, July 21, 2012
Why do good Welders fail weld tests?
Some time around 1981 I completed technical school and was given the opportunity to take my first Welder Qualification test. Cyde Iron Works in Duluth, MN was hiring. Passing meant a $12hr opportunity to join the USWA Local 1424. At that time, unemployment hovered just over 9%. The 4 tests consisted of unlimited thickness, 3G and 4G tests with both Flux-Core (FCAW) and Stick (SMAW). This was the opportunity I had spent the last year training for.
I was at the dinner table when the 3rd shift Foreman called to let me know I had failed the 3G SMAW test. I was devastated. Three days later my instructor called to say they were allowing me a retest.
Over the past 30 years I’ve administered 100’s of (probably closer to 1000) Welder Qualification and Procedure Qualification (PQR) tests. There is little more frustrating then when good Welder, fail. So why do they? I’ve come up with a few ideas…
• Nerves – There is a lot on the line when a Welder enters the test booth. Maybe they’ve been out for a while and finances are tight. Maybe there are 20 Welders competing for 2 positions. Maybe passing gets them that much needed raise.
What ever it is, chill-out. A welder qual test is no different then the work you’ll do every day. You wouldn’t be in that booth if you weren’t ready for it.
• Prep – There is a lot riding on a Welder Qual test, so make it count.
Remove any flame or plasma cut surface from the groove face.
Remove any mill scale from the plate surface for at least a ¼ inch from the joint.
If the bevel does not require a land (root face), insure you grind it to a knife’s edge. If the bevel requires a land, make it consistent.
Remove any mill scale from the backing plate. That joint should shine.
• Technique – Use ALL your best practices.
If given a Weld Procedure (WPS), read it! What should your wire feed speed be? Set It! What should your current or voltage be? Set It! What should your flow rate be? Set it! You do that, and you’re dang near there.
When given run-off tabs, use them! Backing bars should be 2 inches longer than the joint. That’s 1 inch at the start end and 1 inch at the finish end. Use them. Starting a weld on a run-off tab allows your eyes to focus and the arc to settle down. Ending on a run-off tab insures you will fill the joint for its entire length.
Don’t “break” the arc if you don’t have to. If you have to, break it in the center of the joint (I’ve said too much already).
Bring a wire cutter and ALWAYS cut the wire (filler or electrode) before striking the next arc.
Clean the Mig (GMAW) or Flux-Core (FCAW) shielding nozzle after every pass.
When Tig (GTAW) welding, don’t allow the filler wire outside the shielding gas.
When pipe welding, keep your tacks small. Grind them if they’ll let you.
Maintain your purge. Remember, as you finish your root that purge gas needs someplace to go. Give it that opening.
• Ask questions – Lots of them.
Can I make adjustments to the machine?
Can I use some practice material to adjust to this equipment?
If I make a mistake, can I remove it with a grinder?
What is the finish weld visual expectation?
Why are you looking at me like that?
My Uncle Bud was a welding god (at least in my and my families’ eyes). He once took me aside, after a failed Welder Qualification test and said, “The only Welder who’s never failed a weld test is the one who’s not been welding very long.”
There’s a special place in my heart for good Welders that fail a weld test. But for your sake, don’t be that guy.
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