Surface Treatment of Crl2MoV Steel towards Long-Life Cold-Work Dies

摘要

With the rapid development of the automobile industry in China, there is an ever-increasing demand for long-life cold working dies used for punching automobile components. However, the full potential of such advanced surface engineering technologies as PVD coatings and duplex surface treatments in cold work dies has not been realized. In the present study, Crl2MoV steel has been surface engineered by single PVD Ti/TiN coating and duplex treatment combining low temperature plasma nitriding (LTPN) with PVD Ti/TiN coatings. The properties of Ti/TiN coatings in terms of surface morphology, microhardness, load bearing capacity, bonding strength and wear resistance were evaluated by microhardness, scratch and wear tests. The experimental results show that PVD Ti/TiN coatings can significantly enhance the surface load bearing capacity (especially for duplex treatments) and wear resistance of Crl2MoV steel by more than one order of magnitude. This can be mainly attributed to the hard and well-adherent PVD Ti/TiN surface coatings and strong mechanical support of the LTPN sublayer. While two-body abrasive wear prevails for uncoated Crl2MoV, the micropolishing action of the counterface dominates in surface engineered material.