A rush job came in the shop the other day. It was a part made from 4130 chromoly and it was 1-1/4" thick. while thin wall 4130 tubing can be tig welded without a preheat or post heat treatment, ...Thick 4130 requires a preheat in order to avoid hard and brittle areas. Preheating slows the cooling rate and drives off moisture and is needed for high strength low allow steels like 4130 and 4140 in order to avoid cracking and hard brittle zones. | Welding Tips & Tricks

68K views · 287 reactions | Are you working on a project welding 4130 chromoly tube? Don't miss these tips on fitup, proper filler metal, techniques and more for this temperature-sensitive material. bit.ly/3swBtUS | Miller Welders | Facebook