球阀零件复合轧制再结晶演化行为研究

Investigation on recrystallization behavior of combined rolling for ball valve parts

复合轧制是一种将普通环轧与三辊横轧相结合的塑性回转成形新方法,可实现球阀类零件的精密成形。以复合轧制为工艺对象,利用有限元模拟与实验验证相结合的方法,研究球阀零件成形过程中的再结晶演变规律及主要工艺参数对其影响规律。结果表明：球阀零件复合轧制过程中,动态再结晶发生的先后与应变发生的先后有关,而发生的速度则与所处位置的温度和变形速度有关;球阀零件除心部晶粒细化作用不明显外,整个内孔壁等大部分金属都发生明显晶粒细化;随着初轧温度的升高,成形件晶粒尺寸逐渐增大,平均晶粒尺寸均匀性越好;随进给速度增加,晶粒尺寸的轴向差异越明显,且晶粒尺寸会略大,平均晶粒尺寸均匀性越差。

Combined rolling is an advance plastic forming method combining the traditional ring rolling and three rollers cross-rolling technology to realize the precision forming of ball valve parts. Based on combined rolling,the evolution of recrystallization and the influence of rolling parameters on the forming process of ball valve parts were studied by the combination of finite element simulation and experimental verification. The results show that during the combined rolling process,the occurrence of dynamic recrystallization is related to the strain,and the speed of dynamic recrystallization is related to the temperature and deformation speed. In addition,the significant grain refinement is observed in most regions except the heart of metal. With the increasing of original rolling temperature,the grain size of rolling part increases and the uniformity of grain size is improved. However,with the increasing of feeding speed,the axial difference in grain size is more obvious,and the grain size becomes slightly large with a worse uniformity.