Tig welding a forged steel automotive crankshaft

[ftlrobby]

I need a 9/16" dia threaded grade 8 bolt welded into the end of a 1" dia forged steel crankshaft. The bolt is lighty pressed into the shaft. Not certain that the mobile welding company that I contacted actually has the expertise to do the job correctly and I would like to avoid a catastrophic failure down the road . His first attempt broke when I attempted to torque the nut onto the bolt. A crankshaft seal is about three inches away from the weld area so heat is an issue, but I feel I can keep the heat away from the seal. Looking for guidance as to type of rod/wire and pre/post heat instructions. Thank you in advance for any assistance or advice. Bill Robertson.

[aametalmaster]

Why? Just wondering...Bob

[theweldor]

Why ? Is a vry good question and gr 8 bolts do not lend themselves well to welding.

[H80N]

Questions for Clarity

I need a 9/16" dia threaded grade 8 bolt welded into the end of a 1" dia forged steel crankshaft. The bolt is lighty pressed into the shaft. Not certain that the mobile welding company that I contacted actually has the expertise to do the job correctly and I would like to avoid a catastrophic failure down the road . His first attempt broke when I attempted to torque the nut onto the bolt. A crankshaft seal is about three inches away from the weld area so heat is an issue, but I feel I can keep the heat away from the seal. Looking for guidance as to type of rod/wire and pre/post heat instructions. Thank you in advance for any assistance or advice. Bill Robertson.

if I understand this correctly... you are welding this bolt to the crank while the crank is still in the engine?? and possibly still in the car...
not a good idea...
the bolt will be grade ZERO once welded...
and there is no way to restore the heat treat if still in the engine...

Is this by any chance on a Mazda MIATA engine...??

[Silverback]

the short version- when welding anything heat treated you destroy the heat treat, so it will make no difference if it's grade 8, 5, 3 or 0, it will be the same after welding.

I'm with everyone else, what the heck are you doing/what are you working on?

[USMCPOP]

Actually, with low heat and the thermal mass of the crank, it could conceivably quench harden a part of the bolt at the HAZ and make it brittle. In any event, the heat treatment is messed up.

[walker]

Looks like a 1 post wonder!

[hot ticket]

mm-35 feed problem

yes, my finger got stuck on the key board.

[CODE4]

yes, my finger got stuck on the key board.

What are you talking about? This has nothing to do with MM35