厚规格铝压型板辊弯成型工艺与裂纹缺陷分析

Roll forming technology of the thick profiled aluminum sheet and the defect analysis of the cracks

厚规格铝压型板具有重量轻和比强度高等优点,也使其成型过程载荷增大、横向位移增加,成型难度增大。通过分析材料性能和成型工艺的特点,成功开发了厚规格铝压型板辊弯顺序成型工艺,给出了各道次压下规程和轧轮轴向横移量,并对少量压型板角部裂纹缺陷进行了断口SEM和EDS分析。研究发现裂纹断口是典型的微孔聚合型断裂形貌,韧窝内大多包含有夹杂物或第二相颗粒,裂纹多萌生于Al6(FeMn)等硬化相或夹杂物与基体的界面上。通过预退火处理和减慢加工速率等措施可以降低板材加工硬化、提高塑性成形能力,减少裂纹缺陷的发生。

The thick profiled aluminum alloy sheets have the advantages of light weight and high specific intensity However, the profiled sheets are difficult to form because of the increase of the deformed force and shifting displacement. The roll forming technology of the thick profiled A1 alloy sheet was developed by analyzing the features of the roll forming and formability of the metal. The reduction schedule and shifting displacement of each pass were presented, and a few defects at the corner crack were analyzed by the fracture SEM and EDS. Research shows that the fracture is a typical micro-porosity convergent morphology. There are some inclusions and second phases in the dimples, and the cracks are mainly initiated at the interface between the A16（FeMn） hardened phases, inclusions and the aluminum alloy matrix. The pre-heat treatment and the reduction of the deformation rate can reduce the work hardening, improve the formabilitv of the A1 alloy sheet, and reduce the cr^k d^f,~,~t~