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本文重点研究了M_2高速钢连铸坯的凝固组织及其内部质量。测定了铸坯中树枝晶二次枝晶臂间距的大小,从而得到了浇注过程中铸坯的平均冷却速度。同时对M_2高速钢连铸坯的非金属夹杂物作了金相形貌的观察和鉴定,证明M_2高速钢连铸坯的表面质量良好,但内部质量不能令人满意,产生严重的V形偏析,铸坯中发现含钙的大型硅酸盐夹杂和含铝的夹杂物。铸坯的等轴晶带较宽:二次枝晶臂间距较小,因而铸坯的凝固组织致密。除中心部分外其它部位的致密程度皆优于模铸M_2高速钢。
This article focuses on the M_2 high-speed steel billet solidification microstructure and its internal quality. The size of dendrite secondary dendrite arm spacing in the slab was measured, and the average cooling rate of the slab during pouring was obtained. At the same time, the observation and identification of non-metallic inclusions in M_2 high speed steel continuous casting slab showed that the surface quality of M_2 high speed steel continuous casting slab is good, but the internal quality is unsatisfactory and serious V-shaped segregation , Large calcium silicate inclusion and aluminum-containing inclusions were found in the slab. Slab broad equiaxed zone: secondary dendrite arm spacing is small, so slab solidification compact structure. Except for the central part of the other parts of the density are better than molded M_2 high-speed steel.