Shot Peening Process And Its Applications

Author:  P. S. Puranik
Source:  v ICSP & BC - 2
Doc ID:  2001166
Year of Publication:  2001
Abstract:  
Today when a part is not able to withstand the stresses that it is required to, a lot of trial and error effort is put over the part. Its material may be changed, the part may be subjected to heat treatment process or attempt may be made to change the machining techniques. Designer may even go to the extent of changing the design of the part. In many case if analysed properly it will be find out that all the above exercise is totally uncalled for. What may have offered a better solution at a nominal cost could have been the shot peening of the part. Shot peening process increases fatigue life of the part. It toughens the outer surface of the part, it effectively increases the tensile strength of the part and eliminates cracks and other imperfections. This is made possible due to the even compressive stress patterns that are developed during shot peening and also the effective eliminations of microscopic defects in the thin surface shell of the shot peened part. Shot peening is intended to reduce surface tensile stresses in metal parts which are subjected to repeated application of complex load patterns such as axles, springs, gears, shafting, aircraft alighting gear and structural parts for the purpose of improving resistance to fatigue and stress corrosion cracking. Shot peening is also used for application such as to close porosity in casting and to straighten or form the parts. This paper describes the basics of shot peening process. Brief description of the effect of shot peening on the part is described. Various process variables involved in the shot peening process have been discussed. The factors that affect the shot peening process are the size of the shot, the type of the shot, the hardness of the shot, shot velocity and application angle. All these have been discussed in the paper.