4130 to Tungsten welding

By ARacingService Date 11-20-2003 01:09

We have been welding pieces of tungsten into drilled holes in 4130
crankshafts for years, but have never verified the optimum filler material.
Never had a failure by using 309ss rod, but with increasing horsepowers, am now becoming concerned.

By jwright650 (*****)

Date 11-20-2003 18:19

I don't mean to sound like a complete idiot, but for what purpose is the tungsten welded into a crank?
John Wright

By jwright650 (*****)

Date 11-20-2003 18:23

Is it used in balancing?
John Wright

By ARacingService Date 11-21-2003 03:01

Yes, due to the density of the material, (Tungsten), and the lack of clear area to add weight to the counterweights, this method is incorporated to increase counterbalance. This is prevalent on increased stroke engines.

By jwright650 (*****)

Date 11-21-2003 10:57

I was stumped by hearing it called by it's real name. I was used to hearing it called "mallory". Have you tried looking in the forum's archives for the filler metal that would be appropriate for your 4130 cranks? Do a search for chrome moly or 4130 and see if it brings up anything you can use.
John Wright

By GRoberts (***)

Date 11-21-2003 15:32

I think that 309L is a good choice overall. It can tolerate a high level of dilution and resist cracking. Also, austenitic stainless will not reject as much hydrogen into the base metal and thus reduce the chance of underbead cracking also. I'm not exactly sure what affects it would have to melt some of the tungsten into the weld, but there are stainless alloys out there with tungsten already in them, so a little probably won't hurt too much.