Influences of Surface Coatings and Surface Treatments on the Performances of Deep Drawing Operation of Stainless Steel Sheet

Abstract

In this work, the influences of surface coating using TiC, TiCN, TiN, TiAlN film and hard chromiumplating and surface treatment by nitriding on the performances of deep drawing operation of stainless steelsheet were investigated. The die material is SKD11 (JIS), and sheet material is SUS304 having thickness of1 mm. The tests were performed by forming the cups having diameter of 40 mm by those coated dies. It hasshown that the die which surface treated by nitriding gave the best results, i.e. giving maximum LDR valuewhich is 4.8% higher than that of the non-coated die and giving the minimum deep drawing force whichleaded to the most uniform wall thickness of the deep-drawn cup. The dies coated with TiC and TiCN filmshowed the potential to prevent an adhesion of the sheet material onto the die surface which is the cause ofgalling on the surface of the products. On the other hands, the die treated by hard chromium tended toincrease the adhesions. Finally, the die coated with TiN and TiAlN provided poor results compared to thoseof the non-coated die. Since the thickness of both TiN and TiAlN films were very thin, they were found tobe peeled off after a few times of drawing operations.

Keywords : Deep Drawing / Surface Coating / Surface Treatment / Stainless Steel / LDRAbstract1 Researcher,