响应面法在大锻件微观组织质量控制中的应用

以某T型截面大锻件分段多道次成形工艺为研究对象,引入数学统计工具-响应面法(RSM)对该分段、不连续变形下的组织均匀性控制问题进行了研究。将工艺条件-道次进行参数表征,采用有限元方法 (FEM)和响应面法相结合,建立了以改善锻件微观组织质量为评价目标,以坯料温度、压力机速度、上模斜角角度和道次表征量为设计变量的二阶响应模型。研究了设计变量与评价目标之间的作用规律,通过Matlab软件得到了最优锻造工艺和工艺参数组合,即采用3道次成形工艺,坯料温度为440℃,压力机速度为8 mm·s-1,上模斜角角度为160°。采用优化结果进行大锻件的生产试制验证,金像分析显示所成形锻件内部组织均匀,表明了应用RSM和FEM可以有效地对分段多道次成形工艺下的锻件组织均匀性进行控制。

Application of response surface method in controlling of microstructural quality for large forging

For the forming process with subsection and multi-passes of a T-shaped forging part, the controlling homogeneity of step-shaped and discontinuous-deformed microstructure was studied by the mathematical and statistical tool, namely response surface method ( RSM) , and the process condition of the first step was parameterized. Then, the evaluation objective of improving microstructural quality was es-tablished by the combination of RSM and FEM, and the second-order response surface model based on its design variables of billet temper-ature, press velocity, angle of up die was given. Furthermore, the regulation between design variable and evaluation objective was re-searched by Matlab software to obtain the optimal forging process and parameters with temperature of billet 440℃, press velocity 8 mm·s-1 and angle of up die 160°, namely three passes forming process. Finally, the numerical simulation results for large forging part were veri-fied by production, and the internal organization was uniform by metallographic analysis. Thus, RSM and FEM can control the process of multiple passes and steps forming process effectively.