新型马氏体耐热钢G115大型铸件热处理过程有限元分析

为了优化G115钢大型铸件正火及回火热处理制度,通过有限元方法,分析了正火和回火热处理工艺对铸件温度场分布的影响。结果表明,在正火过程中,铸件下端边缘处温度最高且升温速率最快,距上端约1/4处内表面温度最低,且升温速率最慢。在回火过程中,铸件的温度变化规律与正火过程相似。铸件下端边缘处在目标温度下的保温时间最长,上端约1/4截面厚度中心处的保温时间最短。结合加热速率、温差、加热效率及生产成本,正火优选工艺②,回火优选工艺③。采用优化后的热处理工艺所生产G115钢铸件的显微组织及力学性能均匀且明显高于CB2钢。

Finite element analysis of novel martensitic heat-resistant steel G115 heavy castings

In order to optimize the normalizing and tempering treatment processes of G115 steel thick wall hollow castings, the influence of normalizing and tempering heat treatment process on the temperature field distribution of the casting was analyzed by finite element method. The results show that in the normalizing process, the temperature at the lower edge of the castings is the highest and the heating rate is the fastest, and the inner surface temperature at about 1/4 of the upper end is the lowest and the heating rate is the slowest. In the tempering process, the temperature variation of the castings is similar to that of the normalizing process. The holding time of the lower edge of the castings at the target temperature is the longest, and the holding time at the center of about 1/4 section thickness at the upper end is the shortest. Combined with heating rate, temperature difference, heating efficiency and production cost, normalizing process(2) and tempering process(3) are optimized. The microstruture and mechanical properties of the G115 steel casting after heat treating by optimal process are uniform and significantly higher than those of the CB2 steel.