辙叉用贝氏体钢热处理工艺研究  

Research on Heat Treatment of Bainitic Steel Crossing

作　　者：曹栋[1,2] 康杰[1,2] 龙晓燕[1,2] 王艳辉[1,2] 张福成[1,2] 

机构地区：[1]燕山大学亚稳材料制备技术与科学国家重点实验室,秦皇岛066004 [2]燕山大学材料科学与工程学院,秦皇岛066004

出　　处：《机械工程学报》2014年第4期47-52,59,共7页Journal of Mechanical Engineering

基　　金：国家杰出青年科学基金(50925522);国家自然科学基金(50871094)资助项目

摘　　要：对新型辙叉用含Al贝氏体钢进行热处理工艺对比研究。通过对比分析直接空冷、贝氏体开始转变温度(BS)之前快冷后空冷以及等温淬火之后的组织及性能,发现等温淬火的组织具有最佳的综合力学性能,且组织最细。但等温淬火工艺会导致较高的生产成本,并且辙叉本身较大的尺寸导致在实际生产中较难实现。所以根据等温淬火的工艺特点设计出在温度BS之前快冷,温度BS与马氏体开始转变温度(MS)温度期间置于炉中保温缓冷,最后空冷的三阶冷却方式,结果表明三阶冷却方式处理之后的贝氏体钢具有和等温淬火相似的组织形貌及大致相同的强韧性。对接近实际铁路辙叉尺寸的大块试样的不同冷却方式的冷却曲线进行测定,发现油冷不仅能够达到所需的冷速且容易在实际生产中应用。A comparison study is performed on the heat-treatment processes of a new bainitic steel containing A1 used for railway crossing. Microstructures and properties obtained by air cooling, fast cooling before bainite transformation starting temperature （Bs） followed by air cooling and isothermal quenching are analyzed. Results show that the microstructure obtained by isothermal quenching is the finest and possesses the best comprehensive properties. However, higher production cost is caused by isothermal quenching and it is not available in actual production limited by the large size of railway crossing. Based on the character of isothermal quenching process, a three-step cooling method is designed, which consists of fast cooling before Bs point, then slow cooling in furnace between Bs and martensite transformation starting temperature （Ms） and eventually followed by air cooling. It is found that the microstructure, strength and toughness obtained by the three-step cooling method are almost the same as that of isothermal quenching. The cooling curves of the bulk samples close to the actual size of rail crossing under different cooling ways are measured and find that oil cooling can achieve the required cooling rate and easy to realize in actual production.

关 键 词：贝氏体钢 热处理 力学性能 组织结构 铁路辙叉 

分 类 号：TG142[一般工业技术—材料科学与工程]