后混合水射流喷丸工艺对18CrNiMo7-6渗碳钢表面性能的影响

发布时间：2018-08-05 20:38

【摘要】：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。
[Abstract]:Objective to investigate the effect of different water jet shot peening process on the surface properties of 18Cr Ni Mo7-6 Carburizing steel. Methods the surface morphology and surface roughness of the samples before and after shot peening with water jet were studied by using the three dimensional superfield depth microscopy system, the 3D surface topography measurement system, the X-ray residual stress analyzer and the HV-1000 microhardness meter. The variation of residual stress and microhardness with layer depth was analyzed. Results when shot peening by mixing water jet, projectile and water will cause erosion, wear and shearing on the surface of the specimen, which will result in new pits on the surface of the sample. The surface roughness Ra value increases with the increase of the injection pressure P and the target distance H, and decreases with the increase of the velocity v of the nozzle. The maximum microhardness of the samples appeared on the surface, and with the increase of the layer depth, the hardness value decreased gradually. When the spray pressure was 300 MPa, the surface hardness value reached 62.8 HRC, which was 7.35% higher than the initial surface hardness value of the sample. The residual compressive stress introduced by the sample material has the inherent maximum 蟽 mirs. When the residual compressive stress is not up to 蟽 mirs, the maximum residual compressive stress 蟽 mcrs increases with the increase of the injection pressure P. However, there is little change with the jet target distance H and the nozzle moving velocity v. When the introduced residual compressive stress reaches 蟽 mirs, the maximum residual compressive stress 蟽 mcrs will not change, but the maximum residual compressive stress distance from the surface will increase with the increase of jet pressure P. Conclusion after shot peening with mixed water jet, the surface roughness of the sample changes greatly, and the surface microhardness is improved to some extent. The distribution of residual stress is mainly related to the injection pressure P, but not to the jet target distance H and the nozzle moving velocity v.
【作者单位】：郑州大学机械工程学院;
【基金】：国家自然科学基金(51305408) 河南省高等学校重点科研项目(15A460030)~~
【分类号】：TG142.1;TG668

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