"Mild Steel to Chromoly"

by Anthony
(N.Las Vegas)

Can you weld 4130 chromoly to Mild Steel ? If so will the strength be the same, or will it be different because of dissimilarity in the metal ?

I personally never tried welding these two metals together. What type of filler would I use ?

On Chromoly I normally use Oxyweld 65 brand filler. Of course the process I use is Tig (DCEN).

I am asking this question because I am building a race car out of chromoly, but the brackets for the 4 link are mild steel (they were cheaper) or should I spend the extra money for chromoly?

I really enjoy your site and hope to have more questions that baffle my mind LOL.


jody here from weldingtipsandtricks.com.

I would use E70S-2 mild steel tig welding rods.
and btw, I would use this for all your chromoly welds. the oxweld does not have any good stuff like silicon to scavenge the junk.

i bet it spits sometimes.

with E70S-2, the welds will be a tiny bit stronger than the mild steel but not quite as strong as the chromoly. This is normal.

If its thicker than .125" a preheat is called for to slow the cool rate.

good luck,


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