Shot peening of titanium springs

[Theisk]

Hi
Do any of you have experience with shot peening of titanium springs? If so, which type of shots is best for this process? Will stainless steel shots be sufficient?
And is heat treatment after the peening necessary?

My goal with the shot peening is to increase fatique resistans and to have a good looking surface - like this DSP spring:

I hope you can guide me! Thanks in advance
Theis

 

[tbuelna]

Theisk,

Shot peening titanium springs provides the same fatigue life benefits as shot peening other materials. It creates a residual compressive stress in the surface which inhibits the formation of fractures due to tensile stresses. As for what is the optimum form of shot to use for your particular application, you'll have to base that decision on the degree of mechanical strain you wish to impart to your spring surface. Shot size, impact intensity, shot hardness, the relative MoE between the shot and part materials, the angle of shot impact, etc. can all have a big effect on peening results

Stainless steel shot is a compatible material choice for titanium. You do not want to perform any heat treatment on the titanium after shot peening. Maybe just some polishing to remove rolled edges, and some mild surface etching/cleaning.

 

[Tmoose]

MIL-S-13165C available on line.
Specifics about shot and intensity, max temp after peening, etc.
Cancelled, but contains some info maintained in superceding specs

 

[GregRubin]

Theisk,

You may also want to look into HIPPING. Particularly on cast titanium pieces it is a very effective way to reduce fatige issues.

Greg Rubin
Allied Titanium