摘要
回火是残余应力调控的重要手段。采用Gleeble热模拟实验、非等温双回火实验及SEM、TEM组织分析等实验方法,研究了不同预变形及外加应力条件下700L回火碳化物的析出行为。结果表明,在回火过程中,外加应力可以促进碳化物的形核析出。当外加载荷为零时,碳化物主要分布于晶界,且尺寸偏大,为13.9 nm。在50、100 MPa应力回火后,组织中的碳化物数量明显增多,尺寸分别为11.4、11.6 nm,且碳化物的析出位置也由以晶界为主变为晶内弥散分布。在本文研究的应力范围内,回火前增加预变形有效提高了析出物的形核率,并减小了析出物的平均直径。在0MPa下,未变形回火试样的碳化物尺寸为13.9 nm,而5%、10%预变形回火试样的碳化物尺寸为12.9、11.5 nm,较未变形试样分别减小了7.2%和17.2%。经定量统计可知,不同回火工艺下析出物的体积分数几乎保持不变。
Tempering is an important mean of controlling residual stress.The precipitation behavior of 700L tempering carbide under different predeformation and external stress was studied by Gleeble thermal simulation experiment,non-isothermal double tempering experiment and SEM,TEM microstructure analysis.The results show that during the tempering process,applied stress can promote the nucleation and precipitation of carbides.When the applied load is zero,the carbides are mainly distributed in the grain boundaries,and the larger size is 13.9 nm.After 50 MPa and 100 MPa stress tempering,the number of carbides in the microstructure increase significantly,with sizes of 11.4 nm and 11.6 nm,respectively,and the precipitation position of carbides also change from grain boundaries to intragranular dispersion.In the stress range studied,increasing the pre-deformation before tempering can effectively increase the nucleation rate of the precipitates and reduce the average diameter of the precipitates.Under 0MPa,the carbide size of the tempered sample without deformation is 13.9 nm,while the carbide sizes of the 5%and 10%pre-deformed tempered samples are 12.9 nm and 11.5 nm,which are reduced by 7.2%and 17.2%compared with the undeformed samples.According to quantitative statistics,the volume fraction of precipitates is almost constant under different tempering processes.
作者
吴挺
丁文红
祁聪
孙力
刘天武
潘进
张志强
WU Ting;DING Wenhong;QI Cong;SUN Li;LIU Tianwu;PAN Jin;ZHANG Zhiqiang(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China;HBIS Group Technology Research Institute,Shijiazhuang 050023,China;Technology Center,HBIS Group Hansteel Company,Handan 056002,China)
出处
《热加工工艺》
北大核心
2023年第20期140-145,151,共7页
Hot Working Technology
基金
湖北省技术创新专项重大项目(2018AA005)
河北钢铁公司横向项目(2018420112000181)。
关键词
外加应力
预变形
碳化物尺寸
回火
applied stress
pre-deformation
carbide size
tempering
