4130 to x42 pipe

By Tony Svaldi Date 03-25-2008 13:02

Hello,
I was wondering if anyone knows the procedure for welding 4130 heat treat to x 42 pipe. I'm using 325 for preheat, 6010 root and 7018 fill and cap then allowing it to cool in floor dry. I am having cracking issues in the root. If anyone has a better procedure or any info on this your help would greatly appreciated.
Tony

By 357max

Date 03-25-2008 15:18

What schedule are you welding? The 6010 is quite possibly adding hydrogen to the weld. ie hydrogen cracking. Use 7018 all the way out. ie open root, hot, fill & cover.

By Superflux (****)

Date 03-26-2008 01:53

8018 all the way ( or GTAW root) and give it 600 F post heat then bury in floor dry.

By Tony Svaldi Date 03-29-2008 03:24

Ok, I have talked to a welding engineer and he said and I quote "4130 is real funky stuff"... He said that the electrode selection was fine and the pre heat was fine, but the post heat treatment was incorrect. He said that the weld joint needed to be normalized. This consists of bringing the joint up to 1350 degrees, 100 degrees each hour per inch of weld, leaving it at 1350 for two hours, then bring the temp back down 100 degrees each hour per inch of weld. This is only for mild type of steel to a heat treated 4130. The post heat treatment is not necessary for mild type of steel to aneeled 4130.
Tony