4130 chromoly welding with a stainless steel Tig welding rod

Can I weld 4130 with a stainless steel welding rod? That’s a frequently asked soldering question seen on all kinds of internet forums for auto racing, home built airplanes, buggies, casualty racing, bike builders, drag racing, and other sports forums. motor.

Obviously a lot of people are welding 4130 tigs using stainless steel filler rods like the 308, but that doesn’t mean it is better than the old E70s2 mild steel tig rod. Why would you want to use a more expensive welding rod if it wasn’t proven to be better?

I can get an E70S2 tig welding rod for around $ 3 a pound. But the 308 stainless steel rod costs about $ 10 a pound. Other stainless steel rods that some people use for tig welding cromoly, like 309, 310, or 312, cost even more, like more than $ 20 a pound.

I am in favor of paying a little more when something works better but I need proof and the only proof I have found is that people say they like the way stainless steel rods are welded. The solder sure looks good when you use stainless steel rods … all shiny with different colors … and you know what that means?

Any!

The problem with using stainless steel filler rod to weld chrome steel is that different welders will get different results. Not superficial appearance, but microstructure. Each welder will obtain a different degree of dilution and therefore the microstructure of the weld made with stainless filler metal can be unpredictable.

Predictability is very important when it comes to things like airplanes and race cars. Just like old man Hank told his son Bobby on King of the Hill … “Bobby, women love predictability!” Using the E70S2 filler rod results in a more predictable weld microstructure that is less dependent on the welder for good results.

Predictability in both welding and women is underestimated.