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采用Gleeble-3800热应力-应变热模拟试验机对某钢厂生产的Q235B-2B硼微合金化钢230 mm×1800 mm连铸板坯进行高温力学性能测试,得到了600~1350℃温度区间的高温强度和热塑性曲线图。试验结果表明,此钢种第三脆性温度区为750~1000℃,低塑性区间较宽。通过扫描电镜观察,能谱分析发现晶界有许多MnS析出物以及少量的BN与MnS复合析出物。硼微合金化钢裂纹敏感性比较高,这是由于硼在晶界的偏聚以及第二相粒子在晶界的大量析出脆化晶界,影响钢的热塑性,结合热力学理论分析,降低氮含量可减少第二相粒子析出,改善钢种的热塑性。
The mechanical properties of Q235B-2B boron micro-alloyed steel 230 mm × 1800 mm continuous casting slab produced by a steel mill were tested by Gleeble-3800 thermal stress-strain thermal simulator at high temperature. The temperature range of 600-1350 ℃ High temperature strength and thermoplastic curve. The test results show that the third brittleness temperature range of this steel is 750 ~ 1000 ℃, and the low plasticity range is wide. Scanning electron microscopy, energy spectrum analysis found that there are many grain boundary MnS precipitates and a small amount of BN and MnS composite precipitates. Boron microalloyed steel crack sensitivity is relatively high, which is due to boron in the grain boundary segregation and second phase particles in the grain boundary precipitation of a large number of grain boundary embrittlement, affecting the thermoplasticity of steel, combined with thermodynamic theory to reduce nitrogen content Can reduce the second phase particles precipitation, improve the thermoplasticity of steel.