浅谈叶片钢中δ-铁素体含量的控制

Study on Control of δ-ferrite Content in Blade Steel

以低压末级和次末级叶片用钢0Cr17Ni4Cu4Nb为例,重点分析了影响δ-铁素体形成的因素,采用了兼顾化学成分和热加工温度的方法来预测δ-铁素体的形成,证实了EδF由ECr和ET共同决定,控制低的ECr和ET可以有效限制EδF的含量,实验证明ECr的含量控制在8.5以下,锻造温度控制在1 300℃以下可以保证低的EδF。通过降低铁素体形成元素的含量,提高奥氏体形成元素的含量,从而获得较低的铬当量,减少了δ-铁素体的形成,为新型叶片钢的开发设计、制造使用提供了可靠的参考数据。

Taking 0Cr17Ni4Cu4Nb blade steel for low pressure last stage and second last stage for example, the influence factors ofδ-ferrite formation were analyzed in this paper. By using chemical composition and hot process-ing temperature to predict theδ-ferrite formation, it was confirmed that EδF is co-decided by ECr and ET, EδF can be restricted by limiting content of ECr and ET to lower level. Experiments showed that when the content of ECr was be-low 8.5, and forging temperature below 1300℃, low EδF could be ensured. By reducing the content of ferrite forma-tion element and increasing the content of austenite formation elements for the purpose of low chromium equivalent, the formation ofδ-ferrite was reduced, which provide reliable reference data for the development, design, and manu-facturing of new type blade steel.