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FCAW or GMAW of 4130 to 4130

by Marty
(Vienna, Ohio USA)

I need to weld 4130 to itself. The material is 30mm thick and I need a 10 mm fillet. Which process would be best and what would the preheat be? Will a weld blanket be fine to slow cool after welding.


This is just my opinion... If this is a critical weld, the procedure should be proven out by testing such as tensile pulls, bend tests, microhardness , etc.

between gmaw and fcaw, I believe fcaw would be the better choice because of the quick cooling rate of short circuit gmaw.

you can find preheat calculators on the web but my guess is about 300-400 f preheat to prevent hardening.

below is a link code for a free preheat calculator.
its free but i cant vouch for its accuracy.



a 10mm fillet sounds like a pretty small weld for 30 mm thick material.

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