Roundness from Welding

[keffassefa]

I have a Clevis with bore size Ø.763"-.765" and 1.882" long. A shaft of Ø.750 will be welded @ half of the length and the weld need to resist 24000 LB min. pull load.
The issue is this, after welding the clevis bore need to be Ø.760"-Ø.762.
Due to heavy GTAW, the main bore deform and I am not able to maintain the .002" tolerance window, and the part does not shrink uniformly. Any sugestion how to improve the process? Is .002" acheivable with the the current process?

Thanks alot.

 

[DesignerMike]

Whenever I weld ANYTHING I expect some distortion and plan on a post-weld machining operation for toleranced parts. I deal almost exclusively with Stainless which doesn't appreciate the welding process. (there are others that are worse I'm sure). If that is not possible I will re-design the part to move the weld away from the finished surface.

You might be able to predict the distortion after a little history, but every welder and different runs of material will make it almost impossible to stay within .002" and keep it round.

 

[rogzog]

You might experiment with some pre-heating of the weld area and adjacent parts. Also peening of the weld can relieve some of the stress and contraction of the weld area but it's more art than science. Eech welder may get different results.

 

[Tmoose]

1 - weld > stress relieve > finish machine
or
2 - weld > rough machine in several small steps > finish machine

If I already had a batch of parts made I'd get some snug fitting hardened pins (maybe a few of each 0.7595/0.7605/0.7615) and put them thru the bores before welding. After welding, I'd play a torch on the yokes to get them up to nearly a dull red to stress relieve them and allow them to conform to the pin. Depending what the the other finish bore requirements are you might be able to plate the yoke ears and then align hone them. Chevy and Ford reclaimed a million press fit connecting rod small ends that way.