Strange Occurrence During Weld Tests.

[u/HPHatescrafts]

Hi: Weldit

I have a question. I’m a welder/welding supervisor. Today we did our biannual weld tests and four people failed out of nine which has never happened in our shop before but we have some new hires. But there’s more to it than that. Here’s the details.:

CWB 1GF S classification, carbon steel, 1/16” FCAW, 100% CO2. 

I did a 3-4 GF S classification, carbon steel, .045” FCAW 100% CO2 (standard CWB all position check test) and

1 GF S classification, stainless steel .045” 309L FCAW, 100% CO2

I’m not 100% sure of the class of plate but it wouldn’t be garbage. Most of what we buy is 44W/300W. The plates were plasma cut including the bevel but I ground the surfaces to be welded and ground the mill scale off the backing plate and the backs of the test plates, that was also likely 44W/300W. Clean bright metal all around.

Here’s where it got weird. After the tests were done and the coupons cooled with the assistance of a fan, we wrecked four band saw blades trying to cut the straps. Again, the plates were all hand cool. They would get 3/4 of the way through the 3/8” plate then just ripped teeth. We ended up having to cut them with a chop saw.

I did a stainless test as well using stainless plate (also plasma cut) and it passed the bend tests but again, wrecked a bandsaw blade.

One of the guys who failed, even had one strap not conform to the shape of the 1.5” round ram piece that pushed it through the testing jig. It actually looked the way a piece of angle iron does over a pipe. 

As far as the four who failed go, I did some digging and it seems to me at least like they all turned their wire down to get a prettier weld and it cost them in penetration. They were all around 25.5-26 volts and wire speed of 220-240ipm.  When I do a 1GF, I usually run around 27 volts and 275ipm. (1/16" wire)

I would think there was a defect in the plates if it weren’t for my stainless plates wrecking saw blades too. 

I would think the plasma cutting hardened the steel but typically that hardness doesn’t penetrate more than 1mm and I ground all the surfaces. We’ve been cutting our plates with plasma for some years and never had this problem before, but when we got a new table with a swiveling head in 2024, we started cutting the bevel with plasma too whereas with our old table we used to cut them square then mill the bevel on them.

Your feedback is welcome.

[u/ogeytheterrible]

You should switch to Lenox Contestor GT blades, whatever you're using now isn't good for hard material.

[u/HPHatescrafts → u/ogeytheterrible]

It's not supposed to be hard material. It's mild steel.

[u/StockAmphibian4596 → u/HPHatescrafts]

Not my expertise im ndt but is ya shit blunt, cooling fluid contaminated? Very stab in the dark region here. Overly hardened steel id just be going methodically backwards through process of elimination.

[u/ExtensionNewt5842 → u/ogeytheterrible]

I would have to agree

[u/jondrey]

You shouldn't need more than 25V to pass a 1G test

[u/HPHatescrafts → u/jondrey]

Yeah, we normally weld around there.

[u/Apart-Parsley6215]

Is it your sawblades?

[u/HPHatescrafts → u/Apart-Parsley6215]

I don't think so. We're also a machine shop and we cut 1045 and it's much harder than mild steel plate.

[u/Misconformance]

In what way are they failing? Are they following the WPS? Kinda sounds like you have a shitty batch of bandsaw blades.

[u/HPHatescrafts → u/Misconformance]

Possible but it happened to a coupon I did several months ago with a different batch of blades.

[u/Scotty0132]

Were the plates completely cooled before cutting? Also do you have the Mill reports for the steel? Sometimes suppliers will fuck up and some different grade material get mixed together.

The test that failed I would suspect the wire size to be the main culprit 1/16th is a bit on the large size for a CWB test, combined it with them running the volts a tad on the cold side I can see them failing on the fillet side due to lack of fusion. .045 is the largest I Wil run for a FCAW test (and I think may be the largest wire CWB allows on the S class test)

[u/HPHatescrafts → u/Scotty0132]

1/16" is acceptable for testing. I wouldn't use it outside of the 1GF. The plates were cool to the touch. No mill certs.

[u/OldIronSloot]

In blacksmithing cooling with a fan is usually called air hardening. Some munitions factories use that technique and call it air quenching

[u/ragingchestbeard]

Don't cool the welds not with a fan not with spam and definitely don't let Sam use the fan

[u/I_didnt_saythat]

This is far more technical than how I really now to answer. but I wouldn’t be surprised to find the fan actually cools the plates too rapidly. The company I worked for actually wrecked a set of 960ql test plates by letting them rest in the vicinity of a fan.

[u/brobradh77]

All the weld procedures I've ever seen in the ASME and API would do not allow accelerated cooling...as for the saw maybe you had the wrong blade or fed it to fast?

[u/Tecknodude180]

I worked for a fab shop that did nose landing gear for cirrus aircraft. The upper fitting was flame cut out of 4130 chromolly if i remember right and sometimes we had to send them to get annealed to soften the metal before machine otherwise they would brake/ chip tooling all the time. And if that made it past into welding, when we would send the finished part out to final heat treat hardening sometimes the weld or the heat affected zone would crack. Left of scratching or heads sometimes. Eventually we found out we had to test harnesses first before any machining or welding. If it was soft enough we're got the green light. If not we sent it or for annealing first. And then the place closed down.

[u/Scotty0132]

Also what wire are you running?

[u/HPHatescrafts → u/Scotty0132]

This stuff. It's pretty nice and I've bent hundreds of coupons with no problem.

https://www.hobartbrothers.com/product/product-details/fabco-excel-arc-71/

[u/cloneomega]

Control F in codebook "forced cooling"

[u/shorerider16]

The rapid cooling would be suspect and my primary source of suspicion. You would need to know the material, low carbon steel shouldn't harden that much, even if you water quenched it though.

I've never been on the back end of cwb testing but should there not be a paper trail for mill certs on the test plate?

In school on a few occasions i dunked my test plates in water so I could prep them and bend them by the end of the night, none of those ever broke.

[u/Much-Buy-92]

Take one of the plates and have it PMI tested at your local ndt shop to verify it was the correct material

[u/Alli_Woo]

That pattern points more toward hard weld metal/HAZ than bad plate. Running 1/16" FCAW at 25.5–26 V and 220–240 ipm is low heat input, and fan-cooling coupons right after welding can leave hard, brittle weld/HAZ on 44W/300W. Plasma-cut bevels also leave a hard recast/HAZ layer at the edge; grinding the face won’t remove the through-thickness hard band a bandsaw hits. 309L FCAW is tough and work-hardens too, so ripped teeth are plausible. I’d verify preheat/interpass, actual WFS/voltage, and saw blade feed, speed, and coolant. Were the saw cuts going through the weld/HAZ or just base plate, and what blade speed/feed and coolant were used?

[u/Stixx506]

Thats standard procedure at a lot of testing facilities is to put on a rack and fans blow on them. Just about everyone one ive been to does it. Nobody wants to wait 2 hours for it to cool to bend.

[u/Budget_Bison8200]

CWB Auditor here and AWS SCWI, fan cooling shouldn't have caused any issue. I would suspect a direction of rolling of the test plates. Had a client have similar results from having the wrong orientation of rolling. Did the welds fail outside the HAZ (heat affected zone)?