In-situ investigation of oxidation behaviour in high-speed steel roll material under dry and humid atmospheres

The oxidation behaviour of a high-speed steel roll material has been investigated by a high temperature microscope in the temperatures ranging from 550 to 700 °C in both dry and humid atmospheres. In-situ observations indicate that the oxide scales of the high-speed steel first nucleate at the carbides/matrix interfaces, and then rapidly spread to cover the carbides and followed by continuous growth over the whole surface. Water vapour in oxidizing atmosphere significantly increases the oxidation rates of carbides and the matrix. With the increase in temperature, the roughness of oxidized surface becomes higher for both dry and humid atmospheres.