王韶华 沈翃 国栋 冯捷 王晓丽

摘 要：为了研究超高硬度及强度的高速重轨钢，在U75V钢成分基础上进行了调整和优化，向其中添加一定量的Cr合金元素，并与原钢种进行了力学性能对比分析，以便得到成本与性能配合最佳的含Cr合金化重轨钢，使其力学性能优于现有的U75V重轨钢的性能指标，并且在内、外部质量方面能够满足高速铁路重轨钢的使用要求。同时利用Thermocalc热力学软件分析了Cr元素的加入对试验钢夹杂析出物的影响，利用金相显微镜和扫描电镜对试验钢微观组织、晶粒度进行观察分析，探究Cr合金元素对试验钢组织性能影响因素。结果表明：当合金化元素Cr的含量为045%时，重轨试验钢的强度、硬度性能达到最大值;珠光体片层间距最小，晶粒度等级提高，晶粒变得细小。研究结果对于开发超高强度和硬度级别重轨钢的应用具有一定的参考价值。

关键词：黑色金属及其合金;Cr合金化;强度及硬度;力学性能;组织性能;晶粒度

中图分类号：TF764   文献标志码：A

Microstructure and performance of Cr alloy steel

WANG Shaohua1， SHEN Hong2，  GUO Dong3，  FENG Jie3， WANG Xiaoli4

（1.The First Steel Mill， HBIS Group Handan Iron & Steel Company， Handan，  Hebei 056015， China;2.Faculty of Information Engineering and Automation，  Hebei College of Industry and Technology， Shijiazhuang， Hebei 050091， China;3.School of Materials Science and Engineering， Hebei University of Science and Technology， Shijiazhuang， Hebei 050018， China;4. Department of Academic Affairs， Baotou Iron & Steel Vocational Technical College， Baotou， Inner Mongolia 014010， China）

Abstract：In order to study high-speed heavy rail steel with ultra-high hardness and strength， Cr elements is added to U75V steel. The chemical composition of test steel is optimized， and its mechanical properties are analyzed for obtaining the best Cr alloying steel with optimum cost and performance， and that its mechanical properties are superior to the performance of existing U75V steel.It can meet the operating requirements of high speed heavy rail both in outside and inside qualities. Thermodynamic software Thermocalc is used to analyze the influence of Cr element addition on the exhalation of test steel. The microstructure and grain size of test steel are observed and analyzed by metallographic microscope and SEM. Influence of Cr on test steel structure and properties is investigated. When the content of Cr is 0.45%， the strength and hardness of test steel reach the maximum value， the pearlitic laminates have the smallest spacing， the grain grade is improved， and the grain size becomes small. Therefore， this study could provide reference for the application of heavy rail steel.

Keywords：black metal and its alloys;

Cr alloying steel;strength and hardness; mechanical performance;microstructure and performance; grain size

目前，世界各國对钢轨性能的研究主要集中在高强度、高耐磨性上，但以C，Si，Mn，Cr，Nb为合金成分的钢轨研究还鲜有报道。本文从钢铁材料角度开发研究了由新型材料制成的重轨钢，即在U75V重轨钢中加入适量的Cr合金元素，以降低新型重轨钢的成本，提高其强度和硬度，使其力学性能和相关服役性能均好于现有的U75V重轨钢的性能指标，并且在内、外部质量方面能够满足铁路钢轨的使用要求，研究新型重轨钢有非常重要的现实意义。……