Vent: Watching guys skip the pre-heat on a 2-inch thick plate weld drives me nuts

I keep seeing it at the yard, especially on the big pressure vessel jobs. They think because it's a nice day or they're in a hurry, they can just start laying beads. That's how you get cold cracks and a call-back in six months when it fails hydro. My old foreman at the Gary Works would dock your pay for that, and he was right. What's the thickest plate you've ever had to pre-heat before a root pass?

3 comments

3 Comments

jade6392mo ago

Gary Works had a rule for anything over an inch and a quarter. What's the highest interpass temperature you've had to hold on a really thick joint, like on a heavy wall nozzle?

casey9432mo agoTop Commenter

Was that a hard limit or did they let you creep up if you kept the heat input low?

reese55012d agoMost Upvoted

Push back on that. People act like a few degrees over is going to nuke the whole weld and honestly it depends on the material and code. @jade639 I've seen guys at Fab Shop run 300+ on heavy wall nozzles and the radiograph came back clean every time. The interpass temp rules are written for the worst case scenario, not for every single joint out there. Unless you're welding quenched and tempered stuff or something real touchy like that, it ain't the end of the world if you creep up a bit. Hand on the steel and knowing your puddle matters more than staring at a thermometer.