大型中间轴55钢锻件晶粒度控制研究

Research on grain size control of C55E+N forgings for large intermediate shafts

针对55钢中间轴锻件极易发生粗晶的问题,对55钢进行了820~980℃温度下的奥氏体粗化试验,以及770~920℃温度下的正火试验,研究导致该材料晶粒严重粗化的临界温度以及不同正火温度对其微观组织的影响。结果表明:当温度加热到950℃时,55钢晶粒严重粗化;正火温度在860℃时,可以在细化晶粒的同时,消除网状铁素体,获得良好的组织形态。基于研究结果改进中间轴锻造及正火工艺,有效解决了无损检测粗晶的问题。

In view of the problem that coarseness is very easy to occur in C55E+N intermediate shaft forging,austenite coarsening tests at 820~980℃and normalizing tests at 770~920℃were carried out to study the critical temperature leading to severe grain coarsening and the influence of different normalizing temperatures on the microstructure of C55E+N.The results show that the C55E+N grains are coarsened seriously when the temperature is heated to 950℃.When the normalizing temperature is 860℃,the mesh ferrite can be eliminated while the grain is refined,and the good microstructure can be obtained.Based on the research results,the forging and normalizing process of intermediate shaft are improved,and the problem of detecting coarse crystals is effectively solved.