Insights into the High-Temperature Oxidation Behavior of Austenitic Stainless Steel and Influence of Copper on It

Antibacterial austenitic stainless steel containing copper is emerging as an interesting biomaterial. To study the evolution of oxide scale of copper-containing austenitic stainless steel and the influence of copper on the oxidation behavior of austenitic stainless steel, a series of experiments was carried out in this paper. Samples of 304L steel and 4.35%Cu-304L steel were heated to high temperature (600-1250 degrees C/30-120 min) and hot rolled at different pre-rolling temperatures. The evolution of microstructure and composition of the oxide scale were analyzed by scanning electron microscopy, energy-dispersive spectroscopy and x-ray diffraction. It was found that the thickness of the 4.35%Cu-304L scale was reduced compared to the thickness of the 304L scale after heating and rolling, which demonstrated that copper increased the oxidation resistance of austenitic stainless steel. However, mixed oxides containing Cu spinel were present in the oxide layer. Therefore, the copper forms oxides during high-temperature oxidation, which cause further cracking during the rolling process. These results will provide basic guidance for the optimal design of production process for antibacterial austenitic stainless steel.