Laser Surface Texturing of PVD Coatings Applied to Sheet Forming Dies for Stainless Steel

Fiber laser surface texturing was applied on Cr nitride based and other PVD coatings. The field of interest of this study is the cold forming of stainless steel sheet. The laser surface textured coatings were initially investigated in terms of structural and tribological properties in order to select the coating system which achieved the best benefits from laser machining. This set up process was performed at laboratory level with both traditional pin on disk tests using stainless steel as counterpart. The test conditions were set up to generate severe compressive loads and low sliding velocity with boundary lubrication conditions, thus favouring adhesive wear and stainless steel transfer onto the textured coated surface. Results in terms of wear coefficient of friction, gain/losses, material transfer and structural properties are given so as to identify the optimal coating grade to be subject to laser surface texturing.