In production practice, in order to obtain a more ideal shot peening surface, we should start from the following aspects: provide a better original surface, the Ra value should be below 6.3mm; choose a reasonable steel shot diameter and shot pressure; After the diameter steel shot is strengthened, it is covered once with a smaller steel shot and low pressure (the shot peening strength value cannot be changed) to achieve a better surface roughness. The surface of the parts after shot peening should be lightly polished, and the amount of metal removal on the surface must be controlled during polishing. In this way, the strengthening effect of shot peening is not damaged, and the surface roughness can be improved.
Steel shot-strengthening shot peening will cause plastic deformation of the sprayed surface of the part, and change the surface roughness of the part. Surface roughness is a kind of microscopic geometric shape error, also called microscopic unevenness. The surface roughness is the same as the surface waviness and the shape error. It belongs to the geometric shape error of the part. The surface roughness has an important influence on the performance of the machine parts.
The influence of steel shot on the surface roughness of the material is usually in the range of Ra0.6～20mm. Without changing the process parameters, the higher the original surface roughness of the material, the greater the Ra value after shot peening. Production practice has proved that under normal circumstances, if the surface roughness before spraying is below 6.3mm, shot peening can increase or maintain the original surface roughness. If the original surface roughness is above 6.3mm, the surface roughness after shot peening will decrease.
