Study on wear of blanking punches made of JIS-SKH51 treated with fine particle shot peening process.

This research aimed to study the influence of surface treatment by Fine particle Shot Peening (FSP), Nitriding and hard film coating on the wear of punch made from JIS-SKH51 high-speed steel. The experiment was performed by punching a circular workpiece with a diameter of 8 mm, made of 1 mm thick JIS-SPCC cold rolled steel and punching for 10,000 times. The burr height of the workpiece and the weight loss of the punch were measured. The punches used were 1. SKH51 + FSP (media 50 µm) + Nitriding + FSP Polishing + TiCN-PVD, 2. SKH51 + FSP (media 100 µm) + Nitriding + FSP Polishing + TiCN-PVD, 3. SKH51 without treatment, and 4. WC-Co without treatment. The results showed that untreated punch had the highest wear, while WC-Co punch had the lowest wear. The SKH-51 punches, which were surface-treated with FSP, showed similar wear in both conditions, with wear lower than that of the untreated punch but higher than that of the WC-Co punch.