RE-Ca-Ti复合处理对ZG55钢组织与性能的影响

Influence of RE-Ca-Ti Complex Modification on Microstructure and Properties of ZG55 Cast Steel

研究了RE－Ca及RE－Ca－Ti两种复合变质处理方法对改善ZG55钢组织与性能的影响。结果表明，加入适量的RE、Ca及Ti，可使钢的铸态一次晶细化．魏氏组织消除．铁素体由条状大块分布变为均匀的小块分布；非金属夹杂由不规则大块状聚集分布变为点状弥散分布。从而使钢具有较高的机械性能并克服了原钢种的热裂倾向大的缺点。此外，研究还表明，采用RE－Ca－Ti处理比RE－Ca处理效果好，但两者差值并不大，因此，一般情况下，只采用RE－Ca处理即可。

Influence of RE-Ca and RE-Ca-Ti two methods of complex modification on the improvement in microstructure and properties of ZG55 cast steel are studied. Results show that, by adding proper amount RE, Ca and Ti,the size of primary grain of the casting state of the steel can be refined, the widmansttaten structure can be eliminated,the ferrite network can be changed into evenly distributed grains, and the aglomerated polygonal non-metallic inclusions can be changed into dispersively distributed spheroids. Therefore, the steel possesses higher mechanical properties. and the tendency in hot-crack forming is remarkably decreases, its casting properties better than no-modification steel. In adition, researching results also show that, application of RE-Ca-Ti modification has a better effect than that of RE-Ca modification, but the different bettwen these is small. Therefore, in normal condition, the RE-Ca modification can be accepted.