大过冷工艺下珠光体钢亚结构组织及力学性能

摘要

采用TEM和MTS Landmark试验机研究盐浴大过冷工艺下SWRS82B珠光体钢亚结构组织变化及其力学性能,从热力学、动力学和碳原子扩散等方面探索最优热处理工艺.研究结果表明,大过冷工艺下珠光体亚结构组织明显细化,珠光体团尺寸细化至2.39 μm,最小片层间距为62.11 nm,且出现粒径55nm左右的纳米级渗碳体,三者受大过冷工艺的过冷温度和时间的影响较复杂;珠光体钢强度主要由珠光体片层间距决定,而塑性主要受团尺寸影响,二者均受纳米级渗碳体影响,随大过冷工艺的过冷温度和时间的变化而变化.最优大过冷工艺参数为300℃/3 s+550℃.%With TEM and MTS Landmark tester,the changes of pearlite microstructure during supercooling and the effect on the mechanical property were researched,and the optimal heat treatment process was explored based on thermodynamics,kinetics and carbon atom diffusion and so on.The results show that the substructure of pearlite after supercooling is refined significantly,the pearlite colony size is equal to 2.39 μm and the interlamellar spacing is decreased to 62.11 nm,and nanoscale cementite with size of 55 nm appears,the above three are complexly influenced by the supercooling temperature and time.The strength is mainly determined by the interlamellar spacing and the reduction of area by the colony,while both the strength and reduction of area are affected by nanoscale cementite,changing according to the supercooling temperature and time.The optimal process of supercoiling is 300 ℃/3 s+550 ℃.