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用阶梯试样研究了铸件壁厚对不同硅含量灰铸铁组织和力学性能的影响。结果表明,在本试验研究范围内,w_(Si)=1.25的灰铸铁内石墨数量比w_(Si)=2.27的灰铸铁的少。随着铸件厚度的增加,前者过冷石墨减少,基体组织按大量莱氏体+少量珠光体→珠光体+少量碳化物→单一珠光体的规律演变,同时伴随着硬度的减小,而后者由于Si含量较多,促进了合金元素的偏析,过冷石墨反而增多,硬度增大,基体组织均为珠光体+少量铁素体。前者抗拉强度和不同厚度断面的布氏硬度均比后者相应值高。
The effect of casting wall thickness on the microstructure and mechanical properties of gray cast iron with different silicon contents was studied by using staircase samples. The results show that the amount of graphite in gray cast iron with w Si = 1.25 is less than gray cast iron w. (Si) = 2.27 within the scope of this study. As the casting thickness increases, the former reduces the amount of supercooled graphite, and the microstructure of the matrix evolves in accordance with the regularity of a large amount of ledeburite + a small amount of pearlite → pearlite + small amount of carbide → single pearlite, accompanied by a decrease in hardness, Si content is more, promote the segregation of alloying elements, but the excessive increase of cold graphite, hardness increases, the matrix microstructure are a small amount of pearlite + ferrite. The former tensile strength and Brinell hardness of different thickness sections are higher than the corresponding value.