Research on Hybrid Surface Modification by Cavitating Jet

1.通过对不锈钢、硅锰钢、工具合金和碳钢等金属材料进行空化射流冲击实验，利用X射线衍射方法研究了空化射流对金属材料的残余压应力的影响。通过显微维氏硬度随载荷变化的测试，从表面深度评价表面改性效果.结果表明，碳钢的耐蚀性和机械强度同时得到提高，混合表面改性，通过使用空化射流。测量了不同类型喷嘴的流量。从可重复性的角度考虑，圆柱形喷嘴适用于复合表面改性的空化射流.空化的影响进行了测量的PVDF传感器，这是由调查人员开发的，为各种空化条件。空化冲击的强度可以通过调节喷嘴上下游压力来控制.结果表明，空化射流能有效提高铝合金铸件、硅锰钢和碳钢的疲劳强度.冲击面形状对空化流动有一定的影响。为了对齿轮进行喷丸处理，研究了最佳喷丸工艺条件。结果表明，与喷丸相比，空化射流的喷丸表面非常光滑.结果表明，表面粗糙度和残余应力是影响最佳加工时间的主要因素。利用X射线衍射法，通过残余应力来评价表面改性是可能的。

1. Injecting a cavitating jet to metallic materials such as stainless steel, silicon manganese steel, tool alloy and carbon steel, it was revealed that the cavitating jet can introduce compressive residual stress on the metallic materials by means of X-ray diffraction method. It was also revealed to evaluate the surface modification with depth from the surface by using Micro-Vickers hardness testing changing with the load.2. It was revealed that the corrosion resistance and the mechanical strength of carbon steel were improved at same time, i.e., hybrid surface modification, by using a cavitating jet.3. The flow rate of various type of nozzle was measured. The cylindrical nozzle was suitable for the cavitating jet for the hybrid surface modification in view point of repeatability.4. Cavitation impacts were measured by a PVDF transducer, which is developed by the investigators, for various cavitating conditions. The intensity of cavitation impact can be controlled by the upstream and downstream pressure of the nozzle.5. It was shown that the cavitating jet could improve the fatigue strength of aluminum alloy casting, silicon manganese steel and carbonized steel.6. Cavitating flow was affected by the shape of impinging surface. In order to treat gear, the optimum peening condition was investigated. It was revealed that the peened surface by a cavitating jet was very smooth comparing with that of the shot peening.7. It was shown that the roughness of the surface and the residual stress were main factor of optimum processing time. It will be possible to evaluate the surface modification by means of the residual stress using X-ray diffraction method.