Analysis of metallic coating used in matrix conformation of fixing elements in austenitic stainless steel

Abstract

This study aims to test the application of a metallic coating, deposited in forming matrices, to manufacture Austenitic 302 HQ stainless steel screws. One of the problems that occur during the forming process is the adhesion of the conformal material, the Stainless Steel 302HQ, on the forming matrix coated with TiCN (Titanium Carbon Nitride). The metallic coating tested was Titanium Nitride Aluminium, TiAlN. The forming matrices passed through the following processes: machining, polishing to reduce roughness, nitriding and TiAlN coating. The following tests were used to analyze the behaviour of the new coating: analysis of surface integrity by roughness; microstructural characterization tests by SEM (Scanning Electron Microscopy); coating adhesion tests, embossing tests, metallographic analysis: applied to the deformation lines of a screw formed by the first tested matrix. It was determined that the matrices must have a roughness pattern to avoid wear and improve the process. In the forming process it is essential that no flaws should be present. A variable that must be controlled is the alignment between the tool and blank. The tool coated by PVD process, with TiAlN showed considerable productivity, adapting itself to the process.