含钨量对铸态290Cr26MoW耐磨铸铁组织和硬度的影响

铸态合金耐磨铸铁适用于大型或复杂结构耐磨件。通过金相组织观察、X射线衍射相结构分析、图像分析仪定量金相测试和力学性能检测,研究了含钨量对铸态290Cr26MoW耐磨铸铁组织、结构和硬度的影响规律。结果表明,在含0～2.79%W的范围内,随着含W量的增加,铸态290Cr26MoW耐磨白口铸铁的初生基体数量减少,共晶团数量增加,共晶碳化物数量增加;铸态290Cr26MoW耐磨白口铸铁的碳化物结构类型没有改变,M7C3型碳化物为共晶碳化物;铸态290Cr26MoW耐磨白口铸铁基体的奥氏体比例增加,马氏体减少。马氏体多位于共晶团,即共晶碳化物周围。铸态290Cr26MoW耐磨白口铸铁的硬度由共晶碳化物数量和硬度以及基体中奥氏体和马氏体数量比共同决定。

Influences of Tungsten Content on Microstructure and Hardness of As-cast Wear Resistant White Cast Iron 290Cr26MoW

As-cast wear resistant white cast irons are commonly used for large or complex wear resistant parts.The influences of tungsten content on microstructure and hardness of as-cast wear resistant white cast iron 290Cr26MoW was investigated by metalloscope,image analyzer,X-ray diffraction and mechanical properties test in this paper.The results show that with increasing W content within the range of 0~2.79wt%,the amount of primary matrix of the as-cast cast iron 290Cr26MoW decreases,but the amount of eutectic blocks and eutectic carbide increases;the type of carbide in the as-cast cast iron 290Cr26MoW doesn't change,and M7C3 is eutectic carbide.The proportion of austenite in the matrix of as-cast cast iron 290Cr26MoW increases but that of martensite decreases.Martensite exists in eutectic blocks,namely,around the eutectic carbide.The hardness of as-cast cast iron 290Cr26MoW depends on the amount and hardness of the eutectic carbide as well as the ratio of austenite and martensite in the matrix.