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Posted By: Ye Beng Peening & Heat Treatment - 07/09/14 12:03 AM
Hi Dr. Peener,
Peening is basically creating a plastically-deformed surface layer such that compressive residual stresses prevents the formation of surface defects or slows down their growth under fatigue loading. I understand that the recrystallization of deformed grains also occurs more easily and the reduction in recrystallization temperature is related to the degree of deformation. Will the effects of peening be fully- or partially-negated if the peened surface is subsequently thermal-sprayed or baked after electroplating?

For single-crystal alloys, will peening actually cause the formation of unwanted surface grains when the component undergoes a stress relieve heat treatment to reduce/eliminate the effects of fatigue loading? How does re-peening of the same areas salvage the situation?
Posted By: Charlie Re: Peening & Heat Treatment - 11/03/14 09:57 PM
I am not equipped to answer the physics and metallurgy parts of this question, but I can provide insight into temperature ranges. From a proprietary aerospace prime spec:

"When it is necessary to heat parts after peening...the temperatures shall not exceed the following:
Aluminum alloys 250F
Titanium alloys 475F
Nickel Alloys 1000F
Carburized Steels 275F
52100 Steel 285F
All Other Alloy Steels 475F"
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