3 pass fillet

[supercharger]

Hello,
I would just like to get professional opinion on whether a 3 pass fillet weld on 1/4 inch mild steel at 130 amps, 1/16 tungsten, 1/8 A18 Filler would be acceptable for use on an automobile cross member. The fillet would only get welded on one side of the tee as the other side has no access. The weld itself is long about 20 Inches and tig is the only option. A smaller piece made from the same stock using the settings labeled above has been completed, although the piece was 12 inches long about 3 inches of the root were done with 316 SS filler due to exotic metal in the steel (recycled steel??) causing bubble with the A18 filler. Passes 2 and 3 were all done with A18 filler. The weld appears to have good penetration, coloration on the back of the plate but I cannot destructive test this piece. It was welded by a qualified tig welder but the machine that was used could only put out 130 amps and no other option is available. I was informed that due to the relatively low amps it had to be done in three passes with a very small bevel 1/16 inch.

Would you guys be happy with this?

 

[Wendelspanswick]

Difficult to give a definitive answer without seeing the job and to see what loads are being put on the piece, pictures would help.

 

[supercharger]

Difficult to give a definitive answer without seeing the job and to see what loads are being put on the piece, pictures would help.

This is the basic layout of the piece:


|
|
weld |
here |
____|______

Weld can only be on the left side as the other side is covered. It is a tee piece essentially.

 

[hotrodder]

As said without seeing how it's loaded in use/knowing whether it's an important cross member or something to support a radiator etc it's impossible to say. Peronally i'd have zero issues about the multiple pass aspect due to the machine not having enough balls i.e. can't create a large enough weldpool to deposit a weld of suitable size in one pass. Quite often an undersize (for the part thickness) weld is OK as the thickness isn't needed for strength so much as stiffness i.e. shaping something thinner would actually be stronger and lighter if you can get enough shape into it to get the stiffness up

about 3 inches of the root were done with 316 SS filler due to exotic metal in the steel (recycled steel??) causing bubble with the A18 filler

This leaps out as BS... rust/contamination or gas shielding issues are more likely causes of the porosity, stainless filler wire is a kinda bodge in that while it 'fixes' porosity (the contaminants etc are soluble in stainless) it can create some 'funky' metallurgy unless specific flavours of stainless are used- these are 'overalloyed' to account for dilution with carbon steel. Having said that i wouldn't worry about it, very unlikely to cause a problem when it's a short section buried under cover passes. It's more of an issue if/when someone uses stainless wire to produce tiny little 'pretty' welds on carbon steel

 

[supercharger]

As said without seeing how it's loaded in use/knowing whether it's an important cross member or something to support a radiator etc it's impossible to say. Peronally i'd have zero issues about the multiple pass aspect due to the machine not having enough balls i.e. can't create a large enough weldpool to deposit a weld of suitable size in one pass. Quite often an undersize (for the part thickness) weld is OK as the thickness isn't needed for strength so much as stiffness i.e. shaping something thinner would actually be stronger and lighter if you can get enough shape into it to get the stiffness up


This leaps out as BS... rust/contamination or gas shielding issues are more likely causes of the porosity, stainless filler wire is a kinda bodge in that while it 'fixes' porosity (the contaminants etc are soluble in stainless) it can create some 'funky' metallurgy unless specific flavours of stainless are used- these are 'overalloyed' to account for dilution with carbon steel. Having said that i wouldn't worry about it, very unlikely to cause a problem when it's a short section buried under cover passes. It's more of an issue if/when someone uses stainless wire to produce tiny little 'pretty' welds on carbon steel

Thank you sir for your answer. The cross member is to hold suspension arms. I am 100% sure of the issue with the ss filler as I when I was cutting it with my grinder it took a chunk from my 1mm disc. Everywhere else was fine. I polished it back and the metal was defiantly a different color, a darker color, similar to nickel.

Bottom line is: should I have the ss cut out or will it be fine and not cause any issues. This is quite a key part. Everything else is A18 filler. The part will be power coated if that makes any difference. The piece is now finished with the three passes done but I can have it cut out if it will cause a problem..

Thanks

 

[hotrodder]

I'm more bothered by the design (torsional stiffness) than the welding personally but we still don't anywhere near enough about it to comment properly...

Nickel is typically brighter/shinier/less gray than steel, closer to stainless but with a warmer look/slight golden tinge (the yellowish look that appears on worn chrome finishes is the nickel underneath being exposed from people religously polishing it with autosol). From the description sounds to me like it was remnants of millscale that got polished rather than removed and can be enough to result in porosity with TIG, moreso with A18 than with A15. I've broken plenty of 1mm cutting discs but it's never been the metals fault, always been me not paying enough attention and snagging them in the cut

 

[supercharger]

Excluding the design would you be happy with the current welding? Should I get the 3 passes cut out or will it be acceptable for a track day car.

 

[BillJ]

Excluding the design would you be happy with the current welding? Should I get the 3 passes cut out or will it be acceptable for a track day car.

I think without people seeing the design, they cannot comment on the suitability of the weld. Since you are familiar with the design, you could rephrase the question. Tell us what type of weld you would want to use ideally and then ask whether the three-pass weld would be equivalent. It's the only comparison anyone here can make since they don't know enough about the part or its application.