Improvement in galling performance through surface engineering

The aim of the present work was to investigate and compare different surface engineering techniques in terms of galling properties of forming tool steel when sliding against different work materials. The surface engineering techniques included were different grades of polishing, plasma nitriding and different hard coatings, all applied to cold work tool steel respectively. Investigation results indicate that the galling tendency can be greatly reduced by proper polishing of the tool surface. If polished after treatment, plasma nitrided surface will provide further improvement in friction and wear properties of the tool steel and especially for aluminium and titanium alloys reduce the galling tendency. On the other hand, coating selection for improved galling performance of coated forming tool steel greatly depends on the type of work material. In the case of stainless steel, carbon based coatings provide the best protection against the work material transfer, while forming of aluminium and titanium based alloys, requires nitride type coatings.