冷却方式对45CrNiMoVA高强钢显微组织和力学性能的影响  

Influence of cooling method on microstructure and mechanical properties of 45CrNiMoVA high⁃strength steel

作　　者：李家辉 王富雪 方晓英[1] 王洪涛 Li Jiahui;Wang Fuxue;Fang Xiaoying;Wang Hongtao(School of Mechanical Engineering,Shandong University of Technology,Zibo Shandong 255022,China)

机构地区：[1]山东理工大学机械工程学院,山东淄博255022

出　　处：《金属热处理》2024年第2期215-220,共6页Heat Treatment of Metals

基　　金：山东省自然科学基金(ZR2021ME136)。

摘　　要：充分奥氏体化后采用炉冷、空冷、风冷、雾冷、水冷5种冷却方式以及回火处理,对45CrNiMoVA高强钢的微观组织和力学性能开展了研究。用光学显微镜观察高强钢的显微组织,通过MTS E45.105型万能试验机测量其拉伸性能,同时使用HXD⁃1000TM型数显维氏硬度计测量维氏硬度。结果表明,在炉冷条件下,试样的显微组织由珠光体+等轴状铁素体组成;在空冷条件下,冷却速率提高,试样的显微组织转变为以贝氏体为主的贝氏体+马氏体混合组织;随着冷却速率进一步提高,在风冷、雾冷条件下,试样的显微组织中贝氏体的含量减少,马氏体的含量增多;在水冷条件下,试样的显微组织完全为马氏体。炉冷的高强钢硬度和抗拉强度最低,为446.88 HV0.1和1430 MPa,水冷的显微硬度和抗拉强度最高,为815.66 HV0.1和2430 MPa。回火处理后,试样显微硬度降低,抗拉强度降低,但断裂总延伸率提高,展示出优秀的综合力学性能。Microstructure and mechanical properties of the 45CrNiMoVA high⁃strength steel were studied using five cooling methods(furnace cooling,air cooling,forced air cooling,fog cooling,and water cooling)after full austenitization,as well as tempering treatment.The microstructure of high⁃strength steel was observed using optical microscope,and the tensile properties were measured using the MTS E45.105 universal testing machine.At the same time,the Vickers hardness was measured using HXD⁃1000TM digital Vickers hardness tester.The results indicate that under furnace cooling condition,the microstructure of the specimen is composed of pearlite and equiaxed ferrite.Under air cooling condition,the cooling rate increases,the microstructure of the specimen transforms into a mixed structure consisting mainly of bainite and martensite.As the cooling rate further increases,the content of bainite in the microstructure of the specimen decreases,while the content of martensite increases under forced air cooling and fog cooling conditions.Under water cooling,the microstructure of the specimen is completely martensite.The hardness and tensile strength of the specimen furnace cooled are the lowest,being 446.88 HV0.1 and 1430 MPa,respectively,while the microhardness and tensile strength of the specimen water cooled are the highest,being 815.66 HV0.1 and 2430 MPa,respectively.After tempering,the microhardness and tensile strength of the specimen decrease,but the percentage total extension at fracture increases,demonstrating excellent comprehensive mechanical properties.

关 键 词：45CrNiMoVA高强钢 冷却速率 微观结构 力学性能 

分 类 号：TG161[金属学及工艺—热处理]