Custom 450钢异形方管热挤压成形的数值模拟及试验研究

摘要：为了确定Custom 450钢最佳的热变形区间以指导实际热挤压过程的工艺参数设计，采用Gleeble 3800热模拟试验机在真应变为0.2~1.0，应变速率为0.01～10s-1，变形温度为900~1200℃的条件下开展了热压缩试验，确定了该钢发生完全动态再结晶的工艺参数区间；基于热压缩试验结果，采用热力耦合有限元方法对Custom 450钢异形方管在不同挤压工艺参数下的成形过程进行了数值模拟，并依据模拟结果进行实际挤压试验验证，确定了最佳的热挤压工艺。研究结果表明，Custom 450钢异形方管的最佳挤压速度为180mm/s，最佳坯料预热温度为1200℃，依据模拟结果制备的异形方管形状完整，平直度好，具有优良的显微组织与力学性能均匀性。

Numerical simulation and experimental research on extrusion forming of Custom 450 steel special shaped square tube

In order to obtain the best thermal deformation interval of Custom 450 steel to guide the design of the actual hot extrusion process parameters, the Gleeble 3800 thermal simulation testing machine was used to carry out the thermal compression test under conditions of true strain of 0.2-1.0, strain rate of 0.01-10s-1 and deformation temperature of 900-1200℃, and the process parameters for complete dynamic recrystallization of the steel were determined. Based on the results of thermal compression experiments, numerical simulations of the forming process of Custom 450 steel special shaped square tubes under different extrusion process parameters were carried out with thermal mechanical coupled finite element method. The special shaped square tube prepared at the preheating temperature of 1200℃ with extrusion speed of 180mm/s has a complete shape, good flatness, as well as good uniformity of microstructure and mechanical properties.