Experimental and numerical analyses were conducted to explore the influence of DLC/TiAlN-coated die surfaces in sheet-metal forming under dry and oil-lubricated conditions. In this study, ironing and deep-drawing experiments were performed to determine the potential of the DLC/TiAlN coating in the sheet forming of stainless steels under different tribological conditions. The performance and physical properties of the DLC/TiAlN-coated die surface were obtained through load, surface roughness, and wear measurements as well as hardness and microstructure examination. The experimental results indicated that the DLC/TiAlN coating strongly resists galling under dry friction and thin film lubrication conditions that reduces the friction and forming load. The presence of a thin oil film reduces

Increasing demands on reducing abundant use of environmentally hazardous lubricants like chlorinated paraffin oil in production motivates extensive research on dry friction condition. However, the dry friction condition is not favourable, and it causes high friction and severe wear problems. This paper presents the tribological behaviour of a new hard coating, namely double-layer DLC/TiAlN, deposited onto the tool steel surface via a Physical Vapour Deposition (PVD) process. A pin-on-disk tribometer was used to study the long-term performance of DLC/TiAlN coated tool steel under lubricated and dry friction conditions. Surface damage after the experiment was observed by using a light optical microscope (LOM) and also, analysed by measuring wear scar profiles with a tactile roughness profilometer. The results were compared with uncoated tool steel. Based on the experimental result, applying the DLC/TiAlN coating to the tool steel surface has led to a significant reduction of friction and almost no wear scar was observed. The study proved that the DLC/TiAlN coating contributes to the better wear life of the tool steel, thereby improving the tool lifetime.

The present paper focuses on corrosion resistance of hard coatings deposited on tool steel via Physical Vapour Deposition (PVD) process. Three coating types were investigated – TiN, TiCN and DLC/TiAlN. An immersion corrosion test was performed on the PVD coated tool steels in accordance to ASTM G31 standard. With immersion corrosion test in aggressive media of 3.5% NaCl solution at ambient temperature of 33°C and exposure duration of up to 72 hours, the presence of the PVD coatings on the tool steel surface have improved the corrosion resistance of the tool steel surfaces. The results showed that the DLC/TiAlN coated tool steel has the highest corrosion resistance with corrosion rate of 36.58 mm/year, followed by TiCN and TiN coatings with corrosion rate of 42.10mm/year and 96.86 mm/year, respectively. The uncoated tool steel exhibits the lowest corrosion resistance of 140.61 mm/year. The present study suggests that the DLC coating deposited on SKD11 tool steel substrate has better stability than that of TiCN- and TiN-coated surfaces because the DLC can prevent the corrosion more efficiently than TiCN and TiN.