Hard PVD coatings and their perspectives in forming tool applications

The aim of the present work was to investigate the potential of using hard PVD coatings on forming tools. Tribological evaluation of TiN, TiB2, TaC and DLC coatings deposited on a cold work tool steel was carried out in a loadscanning test rig and compared to the behaviour of different uncoated forming tool steels. The special test configuration, where austenitic stainless steel was used as a counter-material, makes it possible to gradually increase the normal load during forward sliding strokes and to correspondingly decrease the load during postreversed ones. In this investigation, the load range was 100 to 1300 N (1 to 5.1 GPa). Experimental results indicate that introduction of a proper hard coating will lead to an improved wear resistance and a longer lifetime of the forming tool. Furthermore, by using hard low-friction coatings excellent anti-sticking properties can be obtained.