高强度钢板方盒形件拉深粘模行为

Galling behavior in square cup drawing of high tensile strength steel

采用方盒形件拉深成形的方法,对高强度钢板SPFC590在干摩擦和半干摩擦条件下的拉深粘模行为进行研究。选用的模具材料分为2类:一类为无涂层模具SKD11,SLD和等温淬火球墨铸铁ADI;另一类为以SKD11为基体的涂层模具TiCN(PVD),TiCN(CVD),TiC(CVD)和DLC-Si(DC-PACVD)。采用无涂层模具时,在半干摩擦条件下仅少数几次拉深就出现宏观粘模现象,模具上粘模产生的位置位于凹模直边底部附近,而没有出现在凹模圆角处,并随着拉深次数的增加向上扩展;拉深工件上粘模产生的位置则位于工件顶部的直边和圆角部分连接处,并随着拉深的进行向下扩展;涂层模具经120次拉深后均未发生明显的粘模,但TiCN(PVD)和TiCN(CVD)涂层模具在凹模底部附近出现了微观粘着物;TiCN(CVD)和DLC-Si(DC-PACVD)涂层模具拉深1000次后均未出现明显粘模现象,但TiCN(CVD)涂层模具上出现了微观粘着物,而DLC-Si(DC-PACVD)涂层模具上没有任何粘着物产生。

The drawing galling behavior of a high tensile strength steel sheet SPFC590 was investigated under semi-dry and dry condition by the square cup drawing method. A cold alloy tool steel （SKD11, SLD） and ADI were used as the non-coated die. TiCN（PVD）, TiCN（CVD）, TiC（CVD） and DLC-Si （DC-PACVD） coated on SKDll were used as the coated die. Using the non-coated dies in semi-dry, the macro-scale galling can clearly observed on die and drawn cup surface after a few drawing cycles. The galling on the die surface occurs at the bottom point of the straight boundary and not at the comer of the die, and grows upward with the drawing cycles. On the drawn cup, the galling starts at the top point of the boundary between the straight and comer edge, and grows downward. Using the coated dies, no remarkable galling is observed on die surface after 120 drawing cycles, but the micro-scale adhesion can be observed on TiCN（PVD） and TiCN（CVD） at the same boundary as the non-coated die. No conspicuous galling can be observed on TiC（CVD） and DLC-Si（DC-PACVD） ever after 1 000 cycles, but micro-scale adhesion can be recognized on TiC（CVD）. No adhesion can be found on DLC-Si（DC-PACVD）.