Researchers from the Laboratory for Tribology and Interface Nanotechnology at the Faculty of Mechanical Engineering, University of Ljubljana, have demonstrated that epoxy-coated steel sheets can significantly extend the service life of stamping tools—even without the use of harmful additives in base lubricants. Their study paves the way for more sustainable and environmentally friendly solutions in the automotive industry.
In automotive production, steel sheets with various coatings are commonly used for stamping into laminations, yet the effect of these coatings on tool wear has not been thoroughly investigated. The study, published in the Journal of Materials Research and Technology (IF = 6.6), provides a detailed analysis of the tribological properties of epoxy-coated steel sheets under both dry and lubricated conditions.
The researchers compared the impact of different lubricants—including water and four base oils with varying compositions and viscosities—on friction and wear in contacts between the coated steel sheet and a tungsten carbide tool. They found that most lubricants extended the durability of the enamel coating in the contact and significantly reduced friction—by more than 70% compared to dry conditions. This suggests that, with proper lubricant selection, it is possible to effectively reduce tool wear using existing coatings, without relying on environmentally problematic additives.
Using Raman spectroscopy and nanoindentation, researchers also investigated how the lubricants affected the coating’s hardness and chemical stability. The greatest softening was observed with water, while paraffinic oils had the least effect. Nevertheless, all tested lubricants reduced both friction and wear compared to dry contact, confirming the high potential of this approach for sustainable manufacturing.
The study shows that even with existing epoxy-based enamel coatings and appropriate base lubricants, it is possible to significantly improve the efficiency and durability of stamping tools. These findings represent an important step toward greener technologies in the automotive sector, where reducing friction is key to improving energy efficiency, lowering maintenance costs, and decreasing CO₂ emissions.
The figure illustrates the distinct removal and transfer paths of the epoxy-based enamel coating to the WC-Co tool under both lubricated and dry conditions, and how these influence the resulting friction behaviour (see below).
