In-situo bservation of the surface oxidation behaviours of a highspeed steel roll
SU Chang-shui1, WANG Xiao-dong1, ZHOU Xun1, XIAO Fu-ren2
1.Hot Rolling Division,Shougang Jingtang Iron and Steel Co.,Ltd.,Caofeidian 063200,China
2.State Key Laboratory of Metastable Materials Science and Technology,College of Materials Science and Engineering,Yanshan University,Qinhuangdao 066004,China
Abstract:The oxidation behavior of a high-V high speed steel was observed in-situ by VL2000DX-SVF18SP ultra-high temperature laser confocal microscopy,and compared with the result of oxidation weight gain which was measured by a NETZSCHSTA449C differential scanning calorimeter/thermal gravimetric analyzer(DSC/TGA)during continuous heating process.The results showed that the microstructure of the high-V high speed steel consisted of spherical MC carbide particles distributed on martensite matrix and eutectic carbides of M7C3and M6C. In the process of continuous heating, when the heating temperature was lower than 480 ℃,the high speed steel almost did not oxidize with the increase of temperature,but when the heating temperature was higher than 480 ℃, the oxidation rate increased significantly with the increase of the increase of the heating temperature. When the heating temperature was over 650 ℃, the oxidation rate increased linearly with the increase of the heating temperature.The oxidation rate of different phases is different.The fast oxidation occurs around V-carbides,and the slower oxidation occurs in eutectic region.