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目的探究不同后混合水射流喷丸工艺对18Cr Ni Mo7-6渗碳钢表面性能的影响。方法运用超景深三维显微系统、三维表面形貌测量系统、X射线残余应力分析仪及HV-1000显微硬度计等,对后混合水射流喷丸前后试样的表面形貌、表面粗糙度、残余应力及显微硬度随层深的变化情况进行分析。结果后混合水射流喷丸时,弹丸和水会对试样表层产生一定的冲蚀、磨损、剪切作用,使试样表面产生新的凹坑。表面粗糙度Ra值随着喷射压力P及喷射靶距H的增加而增大,随着喷嘴移动速度v的增加而减小。试样显微硬度最大值都出现在表面,且随层深的增加,硬度值逐渐减小,喷射压力P=300 MPa时,表面硬度值达到62.8HRC,比试样初始表面硬度值增加了7.35%。试样材料所能引入的残余压应力具有固有最大值σmirs,当引入的残余压应力未达到σmirs时,所产生的最大残余压应力值σmcrs随喷射压力P的增加而增大,但随喷射靶距H和喷嘴移动速度v的改变变化不大。当引入的残余压应力达到σmirs时,所产生的最大残余压应力值σmcrs即为σmirs,不再改变,但是最大残余压应力距表面距离值zm仍会随着喷射压力P的增加而增大。结论后混合水射流喷丸后,试样表面粗糙度变化较大,表层显微硬度有一定提高。残余应力的分布主要与喷射压力P有关,而与喷射靶距H和喷嘴移动速度v关系不大。
Objective To investigate the effect of different post-mixing water jet peening on the surface properties of 18Cr Ni Mo7-6 carburized steel. Methods The surface topography, surface roughness of the post-mixing water jet before and after shot peening were measured by three-dimensional ultra-depth-of-view microscopy, three-dimensional surface topography measurement system, X-ray residual stress analyzer and HV-1000 microhardness tester , Residual stress and microhardness with the depth of the changes were analyzed. Results After mixed water jet peening, the projectile and water will exert some erosion, abrasion and shearing on the sample surface, resulting in new pits on the sample surface. The Ra value of the surface roughness increases with the increase of the injection pressure P and the injection target distance H, and decreases as the nozzle moving speed v increases. The maximum microhardness of the sample appears on the surface, and with the increase of layer depth, the hardness value decreases gradually. When the injection pressure is 300 MPa, the surface hardness reaches 62.8HRC, which is 7.35 higher than the initial surface hardness %. The residual compressive stress that the sample material can introduce has the intrinsic maximum σmirs. When the residual compressive stress introduced does not reach σmirs, the maximum residual compressive stress σmcrs increases with the increase of the injection pressure P, The change from H and nozzle velocity v did not change much. When the residual compressive stress is introduced into σmirs, the maximum residual compressive stress σmcrs is σmirs, which is no longer changed. However, the maximum residual compressive stress from the surface zm still increases with the increase of injection pressure P. Conclusions After the shot blasting with mixed water jet, the surface roughness of the sample changes greatly, and the microhardness of the surface layer increases to a certain extent. The distribution of residual stress is mainly related to the injection pressure P, but has little to do with the jet target distance H and the nozzle moving speed v.