Is there any standard or specification that may detail how soon after shot peening must springs be re-heated?
Is there a time period where stresses induced by shot peening begin to relax?
It is customary to stress-relieve springs
after coiling. We heat them again after shot peening. There are companies that do not believe in this practice. There are even shot peeners that feel the same, and even document this in technical data. Our tests prove that reheating after shot peening can extend the fatigue life by approximately 30-50%. However, we have been seeing new customer specifications popping up with notes such as "Stress relieve within 15 minutes after shot peening".
When asked how they determined the time limit, they are not able to produce any known spec, standard or data to support their requirements.
Please advise on this issue.
