Grit Blasting Titanium

[rbeale98]

Hello,
I am curious about the effect of embedded grit blast particles on component fatigue life. More specifically in the event of an overspray where particles contaminate a titanium lug bore which gets a pressed bushing later on.

I have seen a few comments that titanium is prone contamination. Can anyone recommend a book or article that talks more about this?

I have also seen some articles discussing the impact of grit blasting to crack initation life. In my mind, three factors come into play: compressive residual stress, surface roughness, and foreign object contamination. I am mostly interested in the effect of the particle to act as a crack iniation site in the event of chafing between the lug bore and bushing. Does anyone have any experience with this?

I appreciate any input or discussion that follows. Thanks

[Gordon]

Hi rbeale98

to the Surface Engineering Forum.

Sorry, as yet I've not come across anything specifically relating to effect of embedded grit blast particles on component fatigue life.

In the case where grit blasting is used for substrate preparation for coatings, grit retention/contamination can be an issue, but mainly with that of coating adhesion rather than effect on fatigue strength.

In your specific case, where grit is trap between bore and bushing and particularly where any movement produces scoring marks, I think effect on fatigue could be far more significant.

[rbeale98]

Thanks Gordon,

The grit blast operation in my application is intended to improve the adhesion of a bonded washer that goes over the lug bore. The correct procedure is to blast the washer, not the part itself. It is believed that an operator erroneously blasted the washer surface on the parent material and may have oversrayed into the lug bore before bushing installation. The impact to surface roughness is not of concern, but the contamination of grit particles is definitely of concern. What range of grit size should I look for if I did a microscopic evaluation of the lug bore?

[Gordon]

Hi rbeale98

What range of grit size should I look for if I did a microscopic evaluation of the lug bore?

The same as for the original grit blast media and finer.