稀土变质处理对低合金铸钢组织和性能的影响

Effects of Rare Earth Modification on Structures and Properties of Low-Alloy Cast Steel

变质处理对耐磨铸钢组织和性能有重要的影响,选择合理的变质处理工艺是提高低碳铸钢耐磨性能的重要手段。用稀土硅铁合金对低合金耐磨铸钢进行变质处理,研究了变质剂加入量对铸钢的硬度和冲击韧性的影响。结果表明:当1#稀土硅铁合金加入量为0.25%时,低合金钢的晶粒细化;在控制冷却的条件下,能稳定地得到上贝氏体+下贝氏体+马氏体的复合组织。适量稀土硅铁的加入可以有效地改善低合金铸钢的微观组织、提高低合金耐磨铸钢的力学性能,但稀土加入量不足或过量会使铸钢的性能降低。

Modification treatment has one of important effects on structure and properties of wear resistant steels. The appropriate kind and amount of modification agent are effective methods to improve properties of the steels. The influence of rare earth modification on hardness and the impact toughness of low-alloy cast steel was investigated. The results show that the steel modified with 0.25 % Re-Si-Fe alloy has a good comprehensive properties resulted in refine grain size and upper and lower bainite and martensite structure obtained in the substrate. Proper quantities RE-Si-Fe added can improvement the microstructure and mechanical property of low-alloy steel. It was found that less or excess rare earth in the steel results in hardness and impact toughness of low-alloy steel decreasing.