HG70C热轧带卷的析出物研究

Research on Precipitates of HG70C Hot-rolled Coil Steel

对HG70C钢热轧带卷进行了碳化物、氮化物热力学分析,并结合实验进行了热模拟,统计分析了Nb、Ti的碳、氮化物在低温条件下的析出行为。结果表明,铸坯经单道次1100℃弛豫30 s快速冷却时析出相多,尺寸以35-180 nm为主,少量180-430 nm;在同一弛豫时间,随着温度从1100℃降到850℃的过程中,34-74 nm的小尺寸析出物是逐渐减少的,但在850℃时棒状析出物突然增多,尺寸达370 nm以上;800℃时棒状析出物较少,存在细小针状渗碳体析出物。

Thermodynamic analysis of carbide and nitride in hot-rolled coil steel HG70 C was carried out. And thermal simulation was performed combining the experiment. Precipitation behaviors of carbide and nitride containing Ti, Nb at low temperature were statistica l ly analyzed. The results show that when rapid cooling casting blank in the single pass with relaxation time 30 s at 1100℃, precipitated phases are much more than others. Their sizes are mainly 35-180 nm and a small amount of sizes are 180-430 nm. At the same relaxation time, with the temperature decreasing from 1100℃ to 850℃, the small size of precipitates about 34-74 nm gradually reduce. But the rod precipitates at 850℃ suddenly increase and the size is more than 370 nm. The rod precipitates are less at 800℃, there are fine acicular cementite precipitations.