High Temperature Wear of STD 61 Tool Steels Sliding Against Al-9 percent Si Coated Steels Used for Hot Press Forming

摘要

High temperature wear of STD 61 tool steels sliding against the Al-9 percent Si coated steels used for hot press forming has been studied in comparison with that of the tool steels sliding against the uncoated steels. Wear tests have been performed using a pin-on-disc configuration under an applied normal load of 50N for 20 min with heating the coated and uncoated steels up to 800 deg C. It was found on the worn surface of the STD 61 tool steels sliding against the Al-9 percent Si coated steels that the formation of the glazed layers containing Al transferred from the coated tribopair may contribute to a reduction of the coefficient of friction, and detachment in part occur due to delamination wear, resulting in higher specific wear rate. On the other hand the Fe-oxide wear debris entrapped on the softer surface of the uncoated steels can act as a tribosurface, leading to decreased adhesive wear of the STD 61 tool steels, resulting in a lower specific wear rate.