GMAW Metal Cored Wire

[holdpt]

We have recently attempted to use metal core in place of the 71T-1 because of the deposition and efficiency differences. However, we encountered porosity, incomplete fusion, and crack issues. I would like to know if others have had success or failures with this wire and process.
We closely monitored weld size, gas flow, power source settings and torch push angle. Could this manufacturer have a wire composition formula issue?

 

[REGRUMBLE]

We use metal core extensively for several years without any more problems than other wires. Some metal core wires reqire flux core welders tickets if you are certified to CWB/AWS but require GMAW tickets if you are welding to ASME. What code are you working to and which metal core?

 

[gtaw]

Make sure you are using the parameters, i.e., voltage, wire feed speed, and CTWD, specified by the manufacturer.

Best regards - Al

 

[holdpt]

All monitored variables mentioned above were within the manufacturer's specs. We are welding to D1.1 using prequalified procedures. It appears that this manufacturer's wire is very sensitive to any differentiation of technique or settings. I know of a couple of other companies welding on thicker material that use it to no end, but I am not sure of the type or manufacturer.

 

[gtaw]

Saying that you were within the ranges provided by the manufacturer is like saying you drove from the West Coast to the East Coast and your speed was within the range of 0-90 miles per hour.

Most manufacturer's list the wire feed speed @ a specified voltage using a specific CTWD, not as a range, but specific values. If the voltage used is on the low end, but the wire feed speed is at the high end of a "range" and the CTWD is too short you will not be happy with the results.

Best regards - Al

 

[holdpt]

Let me put it this way. The rep. approved of the exact settings on exactly that machine for that exact joint.

 

[gtaw]

Now we're talking apples and apples.

Usually the problem can be attributed to improper machine settings, contact tip to work distance, angle of the torch, or shielding gas problems.

It sounds like you have eliminated most of those issues.

Best regards - Al

 

[Guest102023]

The most efficient process is the one that gives you the finished product at lowest total cost. MC wire is heavily marketed on the basis of lb/hr, but that can be distracting from the bigger picture.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[kingnero]

metal cored wire typically needs higher amps than solid wire of the same outside dimensions.
Incomplete fusion leads to believe that there's not enough current. Cracks are another issue. What type of cracks are they?
Porosity comes from either problems with your shielding gas, not a good welding position of the torch, or bad wire (amongst other things, but these are the most likely culprits. water cooling leak is also possible).

If your rep approved of the settings, did he lay down a bead or two?

 

[lukin1977]

how big are the pieces your are welding? sounds like the cooling speed is too fast. try preheating and see what happends

lukin1977

 

[holdpt]

These are 2 1/4" bevel groove joints receiving 150F preheats. The crack was longitudinal right in the center of the weld. Gouged out, MT'd, then re-welded with the same result. Ended up running FCAW so that we could finish. Even with the preheating, I still say it is cooling too rapidly.

 

[gtaw]

Exactly which metal core electrode are you using. What is the AWS classification and specification? I've seen what you are describing happen when electrodes intended for thin base metal is used to weld heavy multiple pass grooves.

Best regards - Al

 

[kingnero]

You describe hot cracks, can you confirm? When did the welds crack, right after welding? Please also give chemical composition of both base and weld metal...

 

[holdpt]

Wire specs: E70C-6M H4, AWS 5.18. A36 material.
I watched it crack as soon as the welder's nozzle had cleared my line of vision during welding.
On a side note, I watched another welder's performance on a similar joint and we flipped up the hoods saying how good it looked . . . until I hit it with the needle gun to remove some silicon. It was full of porosity and you could not see it during welding!

 

[gtaw]

This is getting rather tiresome. You seem to be holding back on provide enough information so we can get a better idea of what's going on. If you were really interested in getting help you would be more forthcoming with the information of what and how you are doing this. Personally, I'm tired of the cat and mouse games you are playing.

If you want answers, give the information, all the information needed to make a real assessment of what you are doing and how you are doing it.



Best regards - Al

 

[berkshire]

You asked in your original question if the manufacturer had a wire composition formula issue.
Have you tried a different manufacturers wire to the same specification?
Your last post would indicate that you had a shielding gas issue.
B.E.

You are judged not by what you know, but by what you can do.

 

[holdpt]

GTAW,
Just what new information was presented by me? I presented the defects, the parameters and answered other's questions so that they may help. You need my mother's maiden and my ss #?
If its tiresome, then do not reply and let someone else try to help who is interested. I have not been on here long, but I have witnessed your smart-ass, holier than thou attitude in your answers more than I care for. If I remember correctly, you replied to one of my other posts and it was obvious that you didn't half read it because the reply made no sense.

I can respect your knowledge but the line is drawn there.

 

[Duwe6]

First; check cleanliness of weld area [within 1/2" 12mm of weld margins]. Sounds like an oil and/or "too much anti-spatter spray" problem.

If that doesn't clear up the problem, bring in an expert welder -- not a salesman that also can weld some. Some problems are too subtle to diagnose by mail.

And gtaw is somewhat right. You are not supplying some 'essential observations', but this is most likely because you just don't have the knowledge of what is trivial and what is important about welds and welding. This not an insult; welding is a narrow specialty, but the required knowledge is VERY deep. And when everything goes correctly, nobody needs to know much except the welder.

 

[dbooker630]

When we used E70C-6M metal core in our shop (Coreweld 70) with mild steel we had to ensure that the weld profile was always convex, otherwise we would see the longitudinal cracking along the center of the bead. We eventually switched to ER70S-6 MIG wire because availability was always a problem for us.