Elevated Temperature Wear Behavior of FeCr Slag Coating as an Alternative Coating Material for Caster Rolls

Abstract

The aim of this study is to show that ferrochrome (FeCr) slag, an industrial waste material, can be used as an alternative protective coating material in service conditions for the caster roll surfaces used in the continuous casting line of steelmaking. Atmospheric plasma spray (APS) method was utilized in coating processes. Considering the working conditions of continuous casting production line, the Thermal Barrier Coating (TBC) system was used as a basis for deposition processes. For production of the TBC system, the commercial NiCoCrAlY (Amdry, 45 + 5 mu m) coating powder was initially deposited as metallic bond coat layer onto the surface of AISI 316L substrate, and then FeCr slag layer was successfully deposited as the top coating layer. After the deposition of FeCr slag powder, the resulting coating layer was found to have low porosity with a homogeneous microstructure. Dry sliding wear tests were performed under different loads (7N, 10N and 13N) and temperatures (200, 400 and 600 degrees C) using a ball-on-disc test rig with heating unit. At low loads (7N, 10N) and temperatures (200, 400 degrees C), predominantly spallation type abrasion was observed, while at high load and temperatures (13N, 600 degrees C), the formation of tribolayer and delamination were the dominant wear mechanisms on the surface of FeCr slag coatings. According to the test results, it can be said that FeCr slag powder is a suitable candidate as a protective coating material against adhesive wear at elevated temperatures for caster rolls.