Influence of chemical heat treatment on the mechanical properties of paper knife-edge die

Purpose: In this article mechanical properties together with wear mechanism of paper knife-edge die made of A 681 steel with TiN, TiCN and DLC coating were analyzed. A Paper knife-edge die using in stamping machine, serves a map of complicated graphical projects. However wear resistance is strongly dependent on chemical composition of a paper mainly on the TiO2 content. Design/methodology/approach: In order to optimize the wear resistance of analyzed paper knife-edge die, influence of HS6-5-2 and A 681 substrate with Duplex treatment (vacuum nitriding/ TiN, TiCN and DLC antiwear coatings deposition) were compared. Morphology and mechanical properties (hardness, adhesion) were measured. Findings: The present results show that the duplex treatment (nitriding/TiN) is a very promising technology for protection of paper knife-edge dies due to the uniform, dense structure with a high adhesion to the HS6-5-2 substrate. Hybrid layer fabricated by the gas nitriding and vacuum arc deposition presented improved mechanical properties. Research limitations/implications: In further examinations to compare the results obtained for each layer it should be taken into consideration to manufacture the gradient DLC layers onto nitrided high-speed cutting steel. For full analysis of worked out technology additional examinations concerning investigation of friction coefficient and wear resistance and corrosion features of deposited layers should be conducted. Originality/value: Our experiments provide in this case the evidence of increased mechanical properties of HS6-5-2 steel together with Duplex treatment (TiN coating) instead of A 681 substrate with TiN or TiCN coating.