Welding 4140: Preheat High?
Welding 4140: Preheat High?
(OP)
I am trying to find out how much preheat to do when welding 2.50" thick 4140 bar to 1026 tube. I used Lincoln's calculator and got a preheat of 525 degrees F. I'm not very experienced with welding but this seems a bit high to me.
Here are the 4140 chemical properties I took into account:
C=0.43
Mn=1.00
Si=.35
Cr=1.10
Mo=.35
Thanks in advance,
DAH
Here are the 4140 chemical properties I took into account:
C=0.43
Mn=1.00
Si=.35
Cr=1.10
Mo=.35
Thanks in advance,
DAH





RE: Welding 4140: Preheat High?
RE: Welding 4140: Preheat High?
I would suggest a stress relief operation immediately after welding. Don't let the weldment cool to room temperature and do the stress relief the next day. It will be too late.
Best regards - Al
RE: Welding 4140: Preheat High?
If practical one method we used to handle a few 4140 weldments was to immediately cover the part with vermiculite insulation and allow to cool. Dependent on the weld constraints we either used as welded or if deemed necessary do a stress relief.
RE: Welding 4140: Preheat High?
RE: Welding 4140: Preheat High?
Any type high temperature insulation cloth.
Any type of fibrous insulation used for high temperature. Some types of fiber glass will smoke pretty bad unless you cycle the through an oven, not mama's.
Any other granular insulation. You can even use warm dry sand, Playpen sand.
Old timers used Slacked Lime or an asbestos cloth.
RE: Welding 4140: Preheat High?
Good luck.
Best regards - Al