强化喷丸对渗碳齿轮表面接触疲劳裂纹形成与扩展的影响

Influence of Strengthening Shot Peening on Formation and Extension of Fatigue Crack in Carburized Gear Surface

导致渗碳齿轮接触疲劳裂纹形成与扩展的动力参数是齿轮次表面所受的最大切应力τmax与其表面硬度的比值,减小该比值可延缓齿轮表面接触疲劳裂纹形成与扩展过程,提高齿轮疲劳寿命。分析了强化喷丸工艺对渗碳齿轮次表面所受τmax和表面硬度的影响,通过强力喷丸引入的冷作硬化可使渗碳齿轮表面硬度明显提高;引入的高残余压应力可使渗碳件次表面所受的τmax显著减小。试验表明,齿轮渗碳后再按最佳工艺进行强化喷丸后,可显著提高齿轮表面的疲劳强度。

The ratio of maximum shear stress to stiffness for gear subsurface （τmax）is the dynamic parameter which leads to the formation and extension of fatigue crack in carburized gear surface,and decrease of this ratio can delay the formation and extension of fatigue crack in gear surface and improve gear fatigue life.The influence of strengthening shot peening technique on maximum shear stress and stiffness of carburized gear subsurface are analyzed,which indicates that cold hardening may improve the stiffness of carbonized gear surface and high residual compressive stress may reduce the maximum shear stress obviously.The tests show that the strengthening shot peening treatment for carburized gear can improve gear surface＇s fatigue strength obviously.