重稀土蠕化剂在蠕墨铸铁钢锭模上的应用研究

An Investigation on the Application of Heavy RE-Containing Vermicularizing Alloy to A Heavy Section Vermicular Iron Ingot Mould

浇注400mm×400mm×450mm的厚大断面蠕墨铸铁模拟试块,研究了3种不同稀土蠕化剂和冷铁对模拟试块组织和性能的影响。结果表明,使用冷铁可使共晶凝固开始时间提前30min,共晶凝固时间由4.2h缩短为1.25h;重稀土蠕化剂有良好的蠕化效果和抗衰退能力,模拟试块可获得最高的蠕化率和较好的组织均匀性。采用重稀土蠕化剂处理铁液试制了15t钢锭模,钢锭模附铸试块的蠕化率达到85%,力学性能达到RuT300水平。

By pouring heavy section vermicular iron simulation test block with dimensions of 400mm×400mm×450mm,the effects of three different types of RE-containing vermicularizing alloys and chills on the microstructure and properties of simulation test blocks were investigated. The results showed that the usage of chills caused the beginning time of the eutectic solidification advanced by 30 min,and the duration of eutectic solidification shorten from 4.2 h to 75 min. Among three vermicularizing alloys,the heavy rare earth-containing alloy displayed good vermicularizing effect and ability of anti-fading and by using this type of vermicularizing alloy,the simulation test block with the highest vermicularity and relatively good structure uniformity was obtained. A trial production of an ingot mould with weight of 15t was conducted by using heavy REcontaining vermicularizing alloy to treat the iron melt,and as a result,the vermicularity of the attached test bar of the ingot mould reached 85%,and the mechanical properties reached the level required by RuT 300 grade.