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要使铸锭完全由等轴晶所组成,必须要先在型壁上产生带有缩颈的晶粒,然后在稳定的固体壳生成之前使之游离下来。生成等轴晶组织的主要条件有下列:(1)在型壁上生成有缩颈的晶粒;(2)不使形成稳定的固体壳;(3)促使晶粒从型壁上游离下来;(4)防止已经游离下来的晶粒重新熔化掉。金属必须含有熔质,它能在凝固中的固/液界面上造成偏析。如果液体金属在冷的型壁上冷却太快,则型壁上将有大量晶粒生核
To make the ingot completely composed of equiaxed crystals, it is necessary to first produce the necking with grains on the mold wall and then free the stable solid shell prior to its formation. The main conditions for the formation of equiaxed grains are the following: (1) the formation of necking grains on the wall; (2) the formation of a stable solid shell; (3) the withdrawal of grains from the wall; (4) to prevent the re-melting of the grains have been re-melted away. The metal must contain a melt that segregates at the solid / liquid interface during solidification. If the liquid metal is cooled too fast on the cold wall, there will be a lot of nucleation on the wall