中Mn高Ti耐磨钢中残余奥氏体调控及对其耐磨性能的影响  

Regulation of retained austenite in medium Mn and high Ti content wear-resistant steel and effect on its wear resistance

作　　者：杨建华[1] YANG Jianhua(Hunan Xiangtan Hualin Iron and Steel Co.,Ltd.,Xiangtan 411l0l,China)

机构地区：[1]湖南华菱湘潭钢铁有限公司,湖南湘潭411101

出　　处：《轧钢》2024年第3期11-20,共10页Steel Rolling

基　　金：国家重点研发计划项目(2017YFB0305100)。

摘　　要：对于工程机械用耐磨钢,不仅要求其具有较高的耐磨性,同时还应具有良好的塑韧性。通过中Mn合金成分设计及采用两相区退火工艺,在高Ti马氏体耐磨钢中引入残余奥氏体,使耐磨钢获得了良好的塑韧性和耐磨性能。研究结果表明:随着在630℃两相区退火保温时间的增加,残余奥氏体含量增加,保温8 h后试样可以获得体积分数为32.1%的残余奥氏体,其伸长率为17%。拉伸过程中,两相区退火试样的加工硬化率曲线先下降后略微增加,然后维持稳定,最后开始降低直至试样发生断裂,加工硬化率的上升与应变诱导马氏体转变有关,高的加工硬化率有利于提高钢的伸长率。相对于轧态试样,两相区退火保温8 h试样的硬度降低了120HV,但是相对耐磨性提升了23%。两相区退火试样的磨损形貌为沟槽和剥落坑,而轧态试样的磨损形貌中除了沟槽和剥落坑,还具有较多的塑变疲劳剥落。因为轧态试样的伸长率低,塑性和耐疲劳性能较差,实验钢在反复变形过程中容易因为塑变疲劳发生剥落。此外,在磨损过程中两相区退火试样中的残余奥氏体会发生相变,产生相变诱导塑性效应,提高加工硬化率。拉伸后期的加工硬化率对实验钢磨损性能的影响较大,加工硬化率越高,其耐磨性能越好。X射线衍射结果表明,磨损后两相区退火试样的残余奥氏体体积分数都会下降50%以上。Wear-resistant steel for construction machinery not only requires high wear resistance,but also should have good plasticity and toughness.Through the design of medium Mn alloy composition and annealing in two-phase region,the introduction of retained austenite(RA)in high Ti content martensitic wear-resistant steel can make the wear-resistant steel obtain good plastic toughness and wear resistance.The research results show that with the increase of annealing holding time in two-phase region at 630 C,the volume fraction of RA increased.After holding for 8 h,the volume fraction of RA of sample was 32.1%,and the elongation was 17%.During the tensile process,the work hardening rate curve of the samples annealed in the two-phase region first decreased and then increased slightly,then remained stable,and finally began to decrease until the sample breaks.The increase of the work hardening rate was related to the strain-induced martensitic transformation.High work hardening rate was beneficial to the increase of elongation of the steel.Compared with the rolled sample,the hardness of the sample annealed in the two-phase region for 8 h was reduced by 120HV,but the relative wear resistance was increased by 23%.The wear morphology of the sample annealed in the two-phase region was grooves and spalling pits,while the wear morphology of the rolled sample has more plastic deformation fatigue spalling in addition to grooves and spalling pits.Because of the low elongation,poor plasticity and fatigue resistance of the rolled sample,the experimental steel was prone to spalling due to plastic deformation fatigue during repeated deformation.In addition,during the wear process,the RA in the two-phase region annealed sample will undergo phase transformation,resulting in phase transformation induced plasticity effect and increasing the work hardening rate The work hardening rate in the later stage of tensile had a great influence on the wear resistance The higher the work hardening rate was,the better the wear resistance was.The X-ray re

关 键 词：中Mn高Ti马氏体耐磨钢 残余奥氏体 两相区退火 耐磨性能 加工硬化率 

分 类 号：TG142.72[一般工业技术—材料科学与工程]