磨料水射流喷丸对渗碳GDL-1钢表面完整性及疲劳性能的影响

为研究后混合磨料水射流喷丸对渗碳后GDL-1钢表面完整性及疲劳性能的影响规律,利用X射线应力衍射仪、粗糙度仪、显微硬度仪、金相显微镜、扫描电镜、透射电镜等分析了水射流喷丸强化对试样表面残余应力场、粗糙度、硬度、形貌、组织的变化规律,并用升降法测定了抛光及抛光+水喷丸两种状态下渗碳GDL-1钢拉压疲劳性能。结果表明:试样经水喷丸处理后,表面粗糙度有所增加,并且有磨料撞击形成的小凹坑及在表面残留有玻璃磨料,但同时表层脱碳层大部分被去除,硬度得到显著提升、残留奥氏体含量降低,晶粒得到细化,并且在表面形成一定深度的残余压应力层。经水喷丸处理的试样,其较未经水喷丸的疲劳极限提高了19%,且疲劳源全部在远离表面接近1/2R位置形成,这说明水射流喷丸在表层产生的高残余压应力和晶粒细化可以显著提高渗碳钢的疲劳性能。

Effects of Abrasive Waterjet Peening on Surface Integrity and Fatigue Properties of Carburizing GDL-1 Steel

To study the influence of post-mixed AWJP on the surface integrity and fatigue properties of carburizing GDL-1 steel. Residual stress, roughness, hardness, morphology and microstructure of the AWJP surface were characterized by X-ray diffraction, roughness tester, micro hardness tester, metallurgical microscope, SEM and TEM. Based on the method of changing strengh, the tension-compression fatigue properties of carburizing GDL-1 steel of polishing and polishing+AWJP was studied. The results show that the surface roughness is increased. Many small pits were formed and some glass abrasives are found on the AWJP surface. The most decarburized layer are removed. The hardness of the surface layer was remarkably improved, the residual austenite content is decreased, the grain size is refined, and a certain depth of residual compressive stress layer is formed. The fatigue limit of the AWJP treated specimens is increased by 19% compared with that of the polished specimen and all the fatigue sources are formed close to the 1/2R position from the surface, which indicates that the high residual compressive stress and refined gain produced by AWJP can significantly improve the fatigue properties of carburizing steel.