【摘要】 研究了回火工艺对无限冷硬轧辊表层基体组织的影响。结果表明,经过550℃回火,在基体组织中能获得一种“编织式碳化物”-它南长度为2-4μm的针状碳化物相互交叉编织而成的碳化物长条,分布在下贝氏体边缘,长度与下贝氏体相一致;将基体组织均匀切割成大小不同的小区域,显著改善试样的磨损性能。这种碳化物条的形成机理是由于贝氏体相变引起碳的扩散而形成很窄的高含碳区,在550℃的回火过程中该区域分解成片状珠光体和针状合金碳化物,这些针状碳化物与珠光体中的渗碳体交叉排列而成。更多还原

【Abstract】 Effects of different tempering processes on surface microstructure of indefinite chill cast-iron roller were studied. A new kind of strip-typed microstructure was obtained in the matrix of surface layer by tempering at 550℃ , which is formed by the weaving of some needle-typed carbides with length of 2 -4μm and is called as "woven-carbides". The woven carbides distribute at the margin of lower bainite, and have the same length as that of lower bainite. They divide the matrix into several small parts, and then enhance the wear resistance of the sample significantly. The formation mechanism of the carbides is that long and narrow regions with high carbon concentration were formed due to the carbon diffusion resulted from the lower bainite transformation, and then, the regions transform into a mixture of the pearlite and the needle alloy carbides intersecting with cementite in pearlite by tempering at更多还原