Microstructure Analysis of High Vanadium High-Speed Steel in the Process of Continuous Cooling
As a new type of wear resistant steel, high vanadium high speed steel is attracted much attention at home and abroad. The continuous cooling transformation curves (CCT) is foundation of studying austenite transformation, microstructures and performance of transmutation product, what more, it is reference for heat treatment of steel. So, it is worthwhile to study the continuous cooling transformation of the alloy. In this paper, high vanadium high-speed steels containing 3% C ，8% V and other alloys additions such as Cr, Mo, etc, were investigated on Gleeble-1500D thermal simulation testing machine, which were austenitised at 1000 ℃ and hold for approximately 10 minutes, and then cooled to room temperature at the linear cooling rates of 0.1, 0.25, 0.5, 1, 4 and 10 ℃/s, respectively. The transformation points of overcooling austenite were investigated and the corresponding CCT diagrams were constructed, which almost involved the formation cures of precipitation of carbides, pearlite, banite and martensite. Additionally the phases and microstructures of the steels were observed by optical microscope, transmission electron microscope and X-ray diffraction. The results indicate that, with the cooling rate of 0.1 ℃/s, granular pearlite and bainite can be obtained. When the cooling rate is 0.25 ℃/s, a mixture of pearlite, bainite and martensite are observed. When the cooling rates are above 0.5 ℃/s, there is only martensite exist. Furthermore, with the cooling rate increases, the martensite start transformation (Ms) becomes lower, the residual austenite content increases, and the structure has a tendency of fining. When the cooling rate is 10 ℃/s, the martensitic structure is fine extrodinary and the substructure is made up of high-density dislocation as well as a large number of twins. In addition, when the cooling speed is less than 1 ℃/s, a certain amount of carbide is precipitated at 900 ℃.
LI Yan JI Ying-ping XU Liu-jie WEI Shi-zhong LONG Rui
Mat.Sci.& Eng.College, Henan University of Science and Technology, Luoyang, 471003, China Henan Engineering Research Center for Wear of Material, Luoyang 471003, China Mat.Sci.& Eng.College, Henan University of Science and Technology, Luoyang, 471003, China Henan Engi
国际会议
桂林
英文
1-7
2010-11-16（万方平台首次上网日期，不代表论文的发表时间）