表面高硬度和耐腐蚀性高强贝氏体钢制备新工艺  

New processing routes of fabricating high-strength bainitic steels with high hardness and better corrosion resistance

作　　者：蔡锋 刘曼 徐光[1,2] CAI Feng;LIU Man;XU Guang(State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan 430081,Hubei,China)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081 [2]钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081

出　　处：《钢铁》2022年第6期143-149,共7页Iron and Steel

基　　金：国家自然科学基金资助项目(52004192,52104381)。

摘　　要：铁路运输和工程机械等领域对贝氏体钢的耐磨性和耐腐蚀性具有较高的要求,而表面渗硼、渗铬处理是常见的提高表面硬度和耐腐蚀性的有效方法。在已有的研究工作中,获得贝氏体基体的等温淬火热处理和表面改性处理是分开进行的,工序复杂且生产成本增加。提出制备表面高硬度、高耐腐蚀性中碳高强度贝氏体钢的新工艺,将表面改性处理和贝氏体等温淬火工艺一体化,既可以简化制备工艺,又降低了生产成本、减少了环境污染。采用渗硼/铬-等温淬火一体化新工艺制备表面高硬度、高耐腐蚀性中碳高强贝氏体钢,通过组织观察、硬度测试和腐蚀试验等,对比分析了渗硼-等温淬火和渗铬-等温淬火一体化工艺对中碳高强贝氏体钢组织和性能的影响。结果表明,与仅经过等温淬火工艺处理相比,渗硼/铬-等温淬火一体化工艺处理后,贝氏体钢表面均形成了维氏硬度超过1500HV的渗层(约为贝氏体基体硬度的3.3倍),且在0.5%NaCl溶液中的腐蚀性能明显提高。暴露在0.5%NaCl溶液中3 h后,渗硼层表现出更好的耐腐蚀性能。两种一体化工艺均可制备表面渗层、基体以贝氏体相为主的新型高强贝氏体钢,在相同处理时间下,与渗铬-等温淬火一体化工艺相比,渗硼-等温淬火一体化工艺处理的渗层生长速率快,且渗硼层与贝氏体钢基体的结合强度更高。The wear resistance and corrosion resistance of bainitic steels are highly required in railway transportation and construction machinery,and boronization and chromizing are common effective methods to improve surface hardness and corrosion resistance.In the existing research work,the austempering for obtaining bainite matrix and surface modification technologies for strengthening surface are carried out separately.The processing route is complicated and increases the production cost.New processing routes for fabricating medium-carbon high-strength bainite steels with high surface hardness and high corrosion resistance were proposed,which integrated the surface modification technologies and austempering.The new processes routes can not only simplify the processing treatment,but also reduce the production cost and environmental pollution.The integrated process of boriding/chromizing and austempering(boro-austempering/chro-austempering)were utilized to fabricate medium-carbon high-strength bainitic steel with high surface hardness and corrosion resistance.The effects of boro-austempering and chro-austempering processes on the microstructure and properties of a bainitic steel were compared and analyzed by means of microstructural observation,hardness test and corrosion experiment.The results show that,compared with only austempering process,extremely hard chromizing layer and boronization layer with Vickers hardness of over 1500 HV(about 3.3 times that of bainite matrix)were synthesized on the bainitic steel surface,and the corrosion performance in 0.5%NaCl solution was obviously improved by chro-austempering and boro-austempering treatments.After being exposed to 0.5%NaCl solution for 3 h,the boro-austempered steel yielded better corrosion resistance.A new type of high strength bainitic steel with bainite as substrate and produced layers on the surface can be fabricated by two integrated processes.Under the same treating time,compared with the chro-austempering process,the boro-austempered steel showed a faster grow

关 键 词：渗硼-等温淬火一体化工艺 渗铬-等温淬火一体化工艺 贝氏体 硬度 腐蚀性能 

分 类 号：TG142.2[一般工业技术—材料科学与工程]