均匀大应变棒材轧制新型孔型设计及成形模拟

New Groove Design and Forming Simulation of Uniform Severe Strain of Bar Rolling

通过对传统孔型的讨论和模拟的结果分析,基于大塑性变形原理的晶粒超微细化方法,提出了均匀大应变棒材轧制的新型孔型设计思想,建立了以多向大塑性变形加工为特点的扁椭圆系列孔型。采用非线性有限元法,建立了孔型棒材温轧过程数值分析模型,对比分析了新型孔型系列与传统孔型系列轧件断面内塑性应变分布规律,得出了在满足形状尺寸精确的条件下新型扁椭孔型能更好地将大塑性应变引入到断面中心,并使断面塑性应变趋于均匀,其中心处最大累积应变超过5.0,达到产生超微细晶粒的大塑性变形制备条件。

Through the discussion of the traditional caliber and the analysis of simulation result,a new groove design method for bar rolling of uniform severe strain was proposed based on the principle of severe plastic deformation to manufacture ultra-fine grain（UFG）,and flat-oval groove type with the characteristic of multidirectional severe deformation was developed.The warm rolling numerical model of bar was established and analyzed by nonlinear finite element method.The laws of plastic strain distribution in cross-section of bar were analyzed between the new caliber and traditional caliber.The simulated results indicated that the new flat-oval caliber can be better to introduce the plastic strain to the center of cross section and get uniform severe strain under the condition of qualified size.The largest strain was more than 5.0 at the center of cross section,which meets the severe deformation condition to produce ultra-fine grain.