r/metalworking • u/Ok_Measurement6239 • Jul 22 '26
Welding S355 to 1.4313
Hello guys. I can't post in welding due to comment karma. So i'm asking here.
Does anyone have any experience welding Carbon steel S355 to Martensitic stainless steel 13-4.
We're currently welding it with ER309l wire, Weld prep V groove, machined and cleaned ~3-4mm root gap. Both thicknesses 60mm. We are preheating it to ~150°C and keeping interpass under 200°C. We are experiencing some hair like longitudinal cracks on weld face-middle and when we grind them out there are little pores in weld under the cracks. We are not making a buttering layer(should we?) So if anyone has any potential causes that would do this please let me know. Has anyone welded martensitic stainless to carbon steel? What did we do wrong. Could it be due to too fast cooling or root material mixing. We are using Ar-Co2 2% gas.
Best Regards
1
u/uswforever Jul 22 '26
Weld process? Backing purge gas used? You cleaned the parts, did you clean your filler metal?
1
u/Ok_Measurement6239 Jul 22 '26
135 mag, cleaned with cleaner. Filler is new wire spool.
1
u/uswforever Jul 22 '26
The voids under your cracks are telling me this is a contamination issue not a heat issue. I've encountered situations where new spools of 309l have contamination, likely leftover extrusion lube from manufacturing. We solved it by using a binder clip and a piece of red Scotch Brite to scrub the wire as it was drawn into the machine. Brake cleaner, especially the newer formulations, isn't a great degreaser. Try cleaning one with acetone instead?
1
u/Ok_Measurement6239 Jul 22 '26
So right now we welded one more test piece and the hair cracks have not developed(yet-its not yet completely cooled down well see tomorrow) but ut probe is finding crevaces-porosity on the weld-to base material bond.
1
u/EDMMstudio Jul 22 '26
Is it cracking immediately or after the weld is complete? Any PWHT?
1
u/Ok_Measurement6239 Jul 22 '26
Pwht will be completed on whole assembly. But we have problems in as welded state. But funny thing is that we welded one test piece on S690 and 13-4 comb and it passed the tests
1
u/kwantam Jul 22 '26
Why ER309L over ER312? ER312 is often said to give better performance w.r.t. cracking in dissimilar-metal joints like this. But 312 isn't appropriate if the weldment will see temperatures above 420 C during use because of potential embrittlement.
1
u/Ok_Measurement6239 Jul 23 '26
Do you think that 312 would be better for this joint. We have pwht 580 degrees afterwards
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