摘要:
A rocker arm is made by casting from high chrome cast iron with a microstructure composed of a matrix of martensite and carbide precipitates occupying 30 to less than 45% of the matrix area, and then superfinished by grinding to have a surface roughness of Ra 0.05 to 0.2. The precipitates have an average diameter of 20 micron or less and an average globularity of 40% or more in which the globularity of each precipitate is calculated as a ratio of the real area to the circumcircular area.
摘要:
A high strength high chromium cast iron contains fine particle precipitated hard carbide. The precipitated hard carbide has an average particle size of 20 µm or less, in a martensite matrix with a hardness of Hv 500 or more, and has area ratio of from 30% to 45%. The precipitated hard carbide has a spheroidal ratio (surface area of sphere circumscribing the precipitated hard carbide versus actual surface area of precipitated hard carbide) of 40% or more. The preferred composition (wt%) is C 2.5-3.7; Si 1.0-2.0; Mn 0.5-1.0; Cr 15-20; Ni 0.3-0.7; P at most 0.3; S at most 0.1; optionally one or more of W, Mo, V, Nb, Ta, Ti, and B (total 3-10); rest Fe and impurities.
摘要翻译:高强度高铬铸铁含有细颗粒析出的硬质合金。 在硬度为Hv500以上的马氏体基体中,析出的硬质合金的平均粒径为20μm以下,面积率为30〜45%。 析出的硬质合金具有40%以上的球状比(将沉积的硬质合金与实际的沉淀硬质合金表面积相比的球体的表面积)。 优选的组成(重量%)为C 2.5-3.7; Si 1.0-2.0; Mn 0.5-1.0; Cr 15-20; Ni 0.3-0.7; P至多0.3; S至多0.1; 任选一种或多种W,Mo,V,Nb,Ta,Ti和B(共3-10); 休息Fe和杂质。