响应面法在大锻件微观组织质量控制中的应用

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

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。

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 established by the combination of RSM and FEM,and the second-order response surface model based on its design variables of billet temperature,press velocity,angle of up die was given. Furthermore,the regulation between design variable and evaluation objective was researched by Matlab software to obtain the optimal forging process and parameters with temperature of billet 440 ℃,press velocity 8 mm·s^- 1and angle of up die 160°,namely three passes forming process. Finally,the numerical simulation results for large forging part were verified 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.