Application of shot peening in gears

1、Why gears use shot peening?
With the rapid development of automobile industry in recent years, the life requirements of mechanical parts are also increasing, hence the shot peening process is gradually applied in the automobile industry, particularly in the gear industry.

The proportion of automatic transmission increases year by year, and its requirement for gear strength is higher. Shot peening is a high-efficiency and low-cost process to improve the gear life. A layer of residual compressive stress is introduced into the gear surface, and the gear life after shot peening can be effectively increased by 10-30%, which has been accepted as an effective manufacturing process by the majority of gear manufacturers.

2、What are the failure types of gears?

Gear failure position:

a) Pitting on tooth surface —— contact fatigue —— commonly occurred in large module gears

b) Root fracture —— bending fatigue—— commonly occurred in small module gears


3、Shot peening process commonly used in gear

a) Shot peening intensity: 0.36-0.43mmA

b) Coverage (test piece saturation method): 200% or 400%

c) Recommended shot: CW23 (0.6mm) / HV640 / G2

d) Shot peening area: tooth root (somtimes considering the tooth surface area)

e) Residual compressive stress requirements:

Coverage 200% 400%
Residual stress0um>600Mpa

 f) 齿轮强化设备的形式                                       


                             a)Shot peening                                                                              b) Shot blasting

                     High pressure gas is used to accelerate                                                    The head throwing motor is used to accelerate

                     the shot media to the gear surface.                                                           the shot media throwing to the gear surface.



4、 Shot peening/blasting machines for strengthening automobile gears

a)Gear diameter≤200mm

Recommended equipment: 4RT200-G80II/4/1X  

4-position turning table shot peening machine


b)Gear diameter300mm

Recommended equipment: 4RT300-G80II/4/1X 

4-position turning table shot peening machine



c)Gear diameter≤500mm

Recommended equipment: 2RT500-G80II/4/3X  

2-position turning table 3-axis shot blasting machine



d)Gear diameter≤300mm

Recommended equipment: 5ST300-P380/2/15 

5-position stepping rotary table shot blasting machine