The metal part which operated under alternation loading and subjected to the cycling stress needs to
strengthened by shot peening to improve the fatigue life.
Application: essential components helical spring, spring, twisted, bar gear, transmission part, bearing, cam shaft，
crank and the connecting rod etc.
The landing gear must withstand formidable impulse when the airplane descends, so shot blasting are needed
regularly, and the wing need to do stress-relieving periodic.