The influence of soaking temperature on microstructure of high temperature multi-pass compression deformation for two low carbon steels(steel A:wC=0.032%and wMn=0.25%;steel B:wC=0.165%and wMn=0.38%)is studied on the thermal-mechanical simulator in order to rationalize the hot-rolling schedule of low-carbon steel and to promote the low-temperature heating technology.The results show that the microstructures of steel A are almost not affected by reducing soaking temperature,but the acicular ferrite forms in steel B when the soaking temperature is reduced from 1 200 to 1170℃,due to its smaller initial austenite grain size according to recrystallization kinetics theory.
Three-dimensional atom probe (3DAP) technique has been used to study the nucleation and growth of M23C6 carbide in a supersaturated multi-component Fe-based alloy aged at 800°C. 3D images indicate that the radius of M23C6 carbide after ageing for 10 min is about 9 nm. Concentration profiles of alloy elements in the carbide are also obtained. Combined with PANDAT and Thermo-Calc software, attempts to model the early stages of precipitation are present. The calculated particle size and composition of M23C6 carbide is in good agreement with 3DAP data.
Naqiong ZhuYanlin HeWenqing LiuLin LiShuigen HuangJef VleugelsOmer Van der Biest
