An Investigation of Fineblanked Surface of Cold-Rolled 45 Steel

Fine-blanking process has been paid more and more attention for its shearing surface having low tearing-ratio, low roughness, low cost and high dimensional precision characteristics. It is not suitable for fine-blanking process if the carbon content of non-alloy steel is higher than 0.15% in the traditional view. Only the spheroidization is over 95%, the ideal shearing surface could obtain [1]. Methods of SEM and optical microscopy are used to research the tearing and metallographic characteristics in the region of the tearing of the shearing surface. With the help of the numerical simulation and micro-hardness testing, the tearing on the shearing surface and the shearing surface of fine-blanking is investigated. The conclusion is that without the spheroidizing annealing, 3mm thick cold-rolled 45 steel sheet having a clear flowing fiber of metallographic characteristic can get ideal shearing surface having such fine characteristics as small tear ratio, higher surface hardness and high surface finish by fine-blanking, with the help of optimized parameters from ANOVA and regression method, which considering the interaction between the height of the vee-ring indenter and the distance between vee-ring indenter and blanking contour. The present findings is great significant for expanding the scope of application of fine-blanking technology.