Wear of Cemented Carbide Dies for Steel Cord Wire Drawing

抄録

Cemented carbide dies with five categories of composition, namely, WC–Co straight alloys, TaNbC-, Cr₃C₂- or VC-containing WC–Co alloys and WC–Ni alloys, were fabricated by sintering and HIP treatment. The wear behavior of these cemented carbide dies for drawing steel cord wire is examined, and material properties such as hardness, transverse-rupture strength and corrosion resistance are evaluated. It is found that the TaNbC-containing alloy shows the longest lifetime as a steel cord drawing die, followed by the Cr₃C₂-containing alloy, WC–Co, VC-containing alloy and WC–Ni alloy. The strength and corrosion resistance show no relation with the drawing die life. The hardness has some influence on the die life; for example, within the same alloy category, there is a tendency that the longer die life is obtained for the material with the higher hardness. However, it is not possible to explain simply from the viewpoint of hardness even why the TaNbC-containing alloy has the longest life though the VC-containing alloy has the finest grain size and highest hardness. The wear mechanism of cemented carbide dies for steel cord wire drawing was discussed, focusing on WC/Co interface adhesion.