4140 vs 4130

I work on indy type race cars. Traditionally, the control arms are 4130 and they have to be heat treated when completed. I read an online page for guys building off road race cars who said they built their parts from 4140, because it eliminated the need for heat treat. Obviously I'd rather not have to heat treat, but is this correct? Are the metal properties similar or different?

Thanks for your time.


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I have never heard of that one...Makes no sense to me.

the basic difference is more carbon in the 4140.
which means more hardenability and requires a higher preheat to prevent brittle zones.

I cant see eliminating heat treatment because of something containing more carbon.

usually 4130 is heat treated only as a stress relief treatment and not to make it stronger.

4140 might be a little be stronger after welding but could also be more brittle depending on the procedure used to weld it and the preheat used.

all this rambling and i still say....its a new one on me.

thanks for the post, maybe some of our racing guys out there can weigh in on this one.



jody