Abstract
Abstract Surface coating can greatly enhance the lifetime of cold extrusion die. It is a significant issue to evaluate the performance of coatings and even predict the lifetime of cold extrusion die. In this work, the titanium-based nitride coatings including TiN, TiAlN, and TiAlCrN were, respectively, deposited on the surface of high-speed steel substrate W6Mo5Cr4V2 (M2) by the physical vapor deposition technology. The hardness test, scratch test, Rockwell adhesion test, and pin-on-disc (POD) wear test were carried out aiming to investigate the performances of the three coatings including hardness, adhesion strength, and wear resistance. The results show that the TiAlCrN coating exhibits the highest hardness of 3,033 HV in comparison with TiN coating (1,222 HV) and TiAlN coating (1,916 HV), while it possesses poor adhesion strength and inferior wear resistance. Furthermore, the TiAlN coating presents the highest resistance to wear and spalling from the substrate. In addition, the Archard wear model of the coatings was solved and applied in the finite element model of cold extrusion to calculate the wear depth and lifetime of the cold extrusion dies. The results suggest that TiAlN coating is the optimal option for cold extrusion die as compared with TiAlCrN and TiN coatings. TiAlN coating can prolong the lifetime of the substrate die up to 260%.
Highlights
The excellent performance, especially lifetime, of tools and dies is pursued in a high efficient production, and how to extend their lifetime is an urgent and significant issue
Comparing the coefficient of friction (COF) of the substrate and coatings, it is apparent that the Physical vapor deposition (PVD) coatings can significantly lower the COF of the substrate, which would benefit to the forming process of cold extrusion
The performance of titanium-based nitride coatings including titanium nitride (TiN), TiAlN, and TiAlCrN was evaluated based on a series of mechanical property tests
Summary
The excellent performance, especially lifetime, of tools and dies is pursued in a high efficient production, and how to extend their lifetime is an urgent and significant issue. PVD coatings result in extreme surface hardness, low coefficient of friction (COF), anti-corrosion, and wear resistance properties. Titanium nitride (TiN) is the most common PVD hard coating in use in improving tool and die lifetime today, as it has an ideal combination of hardness, toughness, adhesion, and inertness [3]. In these years, the concept of second-generation Ti(X)N coatings has been proposed on the basis of first-generation TiN [4]. The wear depth and wear distribution of cold extrusion die were computed based on the FEM simulations; the die lifetime was evaluated
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