成形纹缺陷影响因素分析及工艺优化

以侧围外板为代表的难成形零件,对零件表面成形质量要求高,成形后用油石打磨表面后存在成形纹缺陷,影响零件寿命以及涂装质量。应变分析后发现缺陷区域应变量安全裕度远大于10%,在此安全裕度下不会出现严重的减薄而导致表面粗糙。由应变云图可以看出,该区域应变状态为平面应变,平面应变状态下材料晶粒之间对变形比较敏感,晶粒间容易出现变形不协调。通过对材料生产中的热轧温度、卷取温度等工艺参数进行优化改进,改进优化后成形件的材料组织得到了细化,成形件打磨后其材料表面较致密,有效解决了材料的成形纹缺陷。

Affecting factors and process optimization of orange peel

For hard-forming parts such as side panels, the orange peel defects produced by oil stone polishing affect the life of parts and coating quality. It is found that the strain in the defect area is 10% larger than that in the safety margin. However, under this safety mar-gin, it would not appear rough surface caused by serious thinning after margin strain analysis. Furthermore, it is found that the strain state is plane strain. Under the plane strain state the distance between grains in the material is sensitive to deformation, and uncoordinated de-formation is prone to happen. Moreover, process parameters of hot-rolling temperature and curing temperature are optimized in material production, and the material microstructure is refined. Thus, material surface of formed parts is denser after polishing, and the defects of orange peel are solved.