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高速钢W18Cr4V属于莱氏体——马氏体钢,由于含有高含量的碳和碳化物形成元素W、Cr和V,所以在其相组成中,含有30％左右的碳化物,它们硬而脆,并大部是一灰碳化物,即使在热加工温度下,也不能全部溶于固溶体。所以变形始辂在两相区进行,由于相的不同,变形能力也不同,造成变形在微观上的不均匀分布,大大恶化了金属的变形能力。特别在鑄态下,碳化物成骨骼状分布于晶界上,越向钢锭中心,其片越厚并包围着靱性的晶粒,使得塑性大大降低。
High-speed steel W18Cr4V belongs to the class of martensite steel, which contains about 30% carbides in its phase composition due to its high content of carbon and carbide forming elements such as W, Cr and V. They are hard and brittle , And most of the carbide is an ash, even in the heat processing temperature, can not all dissolve in solid solution. Therefore, the beginning of deformation in the two-phase zone, due to the different phase, the deformation ability is also different, resulting in uneven deformation in the microscopic distribution, greatly deteriorated the deformation capacity of the metal. Especially in the as-cast state, the carbides become skeletal in shape on the grain boundaries, toward the center of the ingot. The thicker the film is and surrounding the grains, the plasticity is greatly reduced.