奥氏体化温度和冷却速率对含Nb高碳钢组织性能的影响  

Effects of austenitizing temperature and cooling rate on microstructure and properties of Nb-containing high carbon steel

作　　者：笪光杰 杨忠民[2] 王凯[2] 陈颖[2] 王慧敏[2] 李少华[2,3] Da Guangjie;Yang Zhongmin;Wang Kai;Chen Ying;Wang Huimin;Li Shaohua(Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China;Institute for Structure Steel,Central Iron and Steel Research Institute,Beijing 100081,China;School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学钢铁共性技术协同创新中心,北京100083 [2]钢铁研究总院工程用钢研究所,北京100081 [3]北京科技大学材料科学与工程学院,北京100083

出　　处：《金属热处理》2020年第6期1-6,共6页Heat Treatment of Metals

基　　金：国家重点研发计划(2017YFB0304800,2017YFB0304802)。

摘　　要：通过Gleeble 1500型热模拟试验机对含Nb高碳试验钢进行了不同奥氏体化温度和冷速下的热处理。采用光学显微镜、扫描电镜、硬度测量等试验手段对试验钢的显微组织、硬度和珠光体片层间距进行了观察和测量。结果表明:奥氏体化温度为950℃时,试验钢淬火后晶粒尺寸为34μm,硬度为813 HV5,以0.1~5℃/s冷速冷却至室温的组织为珠光体+铁素体;而奥氏体化温度为1200℃时,淬火后晶粒尺寸为134μm,硬度为827 HV5,以0.1~1℃/s冷速冷却至室温的组织为珠光体+铁素体,冷速为5℃/s时,组织为针状马氏体+少量的铁素体。在1220℃以上Nb全部固溶在奥氏体中,奥氏体化温度过高会导致晶粒过分长大。珠光体片层间距随着奥氏体化温度的升高和冷却速率的提升而变小,片层间距的减小可使硬度值提高。Heat treatment of a Nb-containing high carbon steel at different austenitizing temperatures and cooling rates was carried out by Gleeble 1500 thermal simulation test machine.The microstructure,hardness and pearlite lamellar spacing of the tested steel were observed and measured by means of metallographic microscope,scanning electron microscope and hardness tester.The results show that when the austenitizing temperature is 950℃,the grain size of the tested steel after quenching is 34μm,the hardness is 813 HV5,and the microstructure cooled to room temperature with cooling rate of 0.1-5℃/s is pearlite+ferrite.When the austenitizing temperature is 1200℃,the grain size after quenching is 134μm,the hardness is 827 HV5,and the microstructure cooled to room temperature with cooling rate of0.1-1℃/s is pearlite+ferrite,while that with 5℃/s cooling rate is acicular martensite+a small amount of ferrite.Above 1220℃,all Nb is completely dissolved in austenite,and too high austenitizing temperature will result in too much grain growth.The pearlite lamellar spacing becomes smaller as the austenitizing temperature increases and the cooling rate increases,and the decrease in the lamellar spacing can increase the hardness value.

关 键 词：含Nb高碳钢 奥氏体化温度 冷速 硬度 珠光体片层间距 

分 类 号：TG142[一般工业技术—材料科学与工程]