Welding Tips and Tricks

I have a question on how thick of plate can be welded bare wire like er 70 S not dual shield & we are talking x-ray quality & is there a AWS spec or code on how thick can be welded ?

Hey mate,

Welcome to the forum. The thickness of plate is basically unlimited, An increase in wire size to 1.2mm or 1.6mm will get the ball rolling.

Mick

I *think* under AWS, all GMAW welds must be individually qualified through a WPS, i.e. there are no generic standards as there are for stick on plate, for example.

Mick's right, though, the sky's the limit with multiple passes, and (for efficiency on thick plate) heavier wire.

My suggestion for qualifying an x-ray procedure would be to use -S2 wire (rather than the more common -S6), and do the extra pre-weld and interpass cleaning, to avoid silicon inclusions.

Two cents... I've never actually had to qualify a GMAW procedure, just weld them.

Steve S

thank you for you're comments . I was talking with a coworker about multi pass mig vertical up verses fcaw . he made the statement that there is no way to make clean multi pass gmaw weld said you would trap silica in the wagon tracks or the under cut that you get when you weld vert up. I called B.S. and said he is full of it I personal have welded frame cracks up with super arc L56 0.030 and never no problem . Some of the cracks where big I would air arc out the crack at 45 deg with a 1/4'' gap grind it to remove any carbon and slag pre heat to 350 deg welding the first pass an open butt weld welding it down filling the gap run a needle gun on it to remove any silica and the next pass would be vert up chip it and repeat until it was welded out. when I got under cut I would grind it to make Shure it was clean and weld a down hand to flush it up or even it out and continue welding it out vert up . The cover passes I would weld down hand and grind it using a 60 grit flap disk to eliminate stress risers in the frame. The frame is 1 1/4 in thick . some times I would use a combination of L56 for the root and 71m fcaw to fill and cap or cap L56 and grind . the frame crack would be 4 in to 30 in long I would typically fill with 71m fcaw on the longer cracks it just welds faster. never had no problems or re work come back. the frames are boxed there is no way to back gouge your root weld. I have in the past put in back up strips in but cracks are generally not strait lines so back up strips are time consuming to make and in stall if you can make an open butt root weld proficiently you really don't need back up strips. any way my co worker thinks I am full of it what do you think?

new job different people and they think there way is the only way to do some thing asked the boss if I could weld with the any wire I wanted he said no that lincoln 71m duel shield fcaw has more tinsel strength than Lincoln super arc L56 gmaw . I thought they where both 70,000 psi tinsel strength?

Welcome to the site. Moved your topic over to Mig & Flux Core where you'll get more people looking at this thread.

Steve is correct as the AWS does not have a pre-qualified structural welding test for GMAW-S. They do have tests that allow GMAW-S in their sheet metal code with a thickness limit of 3/16". That means you have to go through the qualification procedure to use GMAW-S as on a "code level" structural weld. It is a fairly involved procedure but it can be done.

I just went through a round of tests at school with 2 students in my certification practices course. I test my students with the same test for all processes. Limited thickness 3/8" plate, open groove, 60* groove angle. They always pass SMAW with no problem and pass GTAW as soon as they figure out their land and gap to stop suck-back. GMAW-S is the process that gives the most problems even though the visual may be a beautiful weld. The problem seems to be at the toes of the second pass. Fusion and silicon are the problems. Remember that GMAW-S is notorious for cold lap. A switch to ER70S-2 wire did help with the silicon. With a little more practice and carefully watching the puddle both passed vertical up.

This shows that the procedure could be qualified and I would really like to have a WPS if anyone on hear goes through the process.

Kevin