钢材的冲击磨损性能研究

发布时间：2018-06-23 08:49

本文选题：塑性变形 + 45号钢　；参考：《青岛理工大学》2011年硕士论文

【摘要】：本文首先，为理解点接触热弹流薄膜润滑问题，研究了单个表面划痕对乏油条件下非牛顿点接触热薄膜润滑的影响。分析中同时考虑了牛顿流体模型和Ree-Eyring流变模型，研究了划痕的存在对乏油工况下薄膜润滑特性的影响。结果表明，在乏油条件下，处于静止表面上接触中心的横向划痕前后的压力和温度都有尖锐的升高，且这种升高随乏油程度的严重而增加。在乏油条件下，，表面粗糙的存在更不利于润滑，易于造成润滑失效。其次，对钢材在往复冲击载荷作用下的塑性变形和表面损伤行为进行了实验研究。利用时间继电器和电磁铁控制施力，在冲击磨损实验台上进行冲击实验。以一定的频率用钢球往复冲击45号钢、40Cr钢、调质45号钢及表面具有不锈钢焊层的45号钢实验盘。实验研究了试件盘在干接触及两种不同粘度润滑油润滑工况下，随冲击载荷大小及冲击次数的改变，材料表面冲击凹坑的变化。结果发现，冲击使材料表面发生了塑性变形和磨损，塑性变形存在于冲击的每一阶段。磨损量随冲击次数的增加而增加。冲击坑深度及体积随冲击次数的增加呈增大趋势。使用润滑油，会改变冲击压力的分布形式，可在一定程度上有效抑制冲击磨损给材料表面带来的损伤，降低塑性变形。使用PB1300高粘度油冲击时凹坑中心还会出现乏油现象，因此PB1300油润滑在特定工况时，凹坑中心局部甚至会发生非常显著的塑性变形。冲击过程中，凹坑中心会产生一定的热量，并不断向边缘传递，导致凹坑边缘产生凸起。有润滑油存在时，会有利于将冲击产生的热量向凹坑边缘传递，从而使凹坑边缘凸起更加明显。润滑油粘度越高，冲击产生的热量越多，凹坑肩部凸起就越明显。在相同接触条件下凹坑肩部凸起高度随冲击次数及载荷的增加而有所增加。干接触冲击时，凹坑内部出现微细颗粒碎化及微裂纹现象。润滑油工况下，凹坑内部也会出现微裂纹及表面剥离现象。微细颗粒碎化及微裂纹的程度随载荷及冲击次数的增加呈增大趋势。
[Abstract]:In order to understand the problem of point contact thermal elastohydrodynamic film lubrication, the effect of single surface scratch on non Newtonian point contact thermal film lubrication in the absence of oil has been studied in this paper. The Newtonian fluid model and the Ree-Eyring rheological model are taken into account in the analysis, and the influence of the scratch on the lubrication characteristics of the film under the condition of lack of oil is studied. The results show that the pressure and temperature before and after the transverse scratch at the contact center on the stationary surface increase sharply under the condition of lack of oil, and this increase increases with the degree of oil shortage. Under the condition of lack of oil, the existence of surface roughness is more unfavorable to lubrication, and it is easy to cause lubrication failure. Secondly, the plastic deformation and surface damage behavior of steel subjected to reciprocating impact loading are studied experimentally. The impact test was carried out on the impact wear test bench by using time relay and electromagnet to control the force. Steel 45 steel was subjected to reciprocating impact with steel ball at a certain frequency, and 45 steel was quenched and tempered with stainless steel welding layer. Under dry contact and two kinds of lubricating oil lubricating conditions with different viscosity, the impact pits on the material surface were studied with the change of impact load and times of impact. The results show that plastic deformation and wear occur on the surface of the material due to impact, and plastic deformation exists in every stage of impact. The wear rate increases with the increase of impact times. The depth and volume of impact pits increase with the increase of impact times. The distribution of impact pressure will be changed by using lubricating oil, which can effectively restrain the damage caused by impact wear on the material surface and reduce the plastic deformation to a certain extent. When high viscosity oil PB1300 is used to impact the pit center will also appear the phenomenon of lack of oil so PB1300 oil lubrication in a specific condition the center of the pit will even occur a very significant plastic deformation. During the impact process, the center of the pit will produce certain heat and transfer to the edge, which will cause the edge of the pit to protrude. In the presence of lubricating oil, the heat generated by impact will be transferred to the edge of the pit, which will make the edge of the pit more prominent. The higher the viscosity of the lubricating oil, the more heat the impact produces and the more prominent the pit shoulder is. Under the same contact conditions, the height of shoulder bumps increases with the increase of impact times and loads. During dry contact impact, micro-particles and microcracks appear in the pit. Under the condition of lubricating oil, microcracks and surface exfoliation will also appear in the pit. The degree of microparticle fragmentation and microcrack increase with the increase of load and impact times.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH117

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