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使用真空感应炉冶炼了试验钢,采用不同的控制轧制+超快冷工艺将试验钢轧成12 mm厚的钢板,对钢板金相组织进行了观察,对拉伸和冲击性能进行了检测。结果表明,试验钢组织均为贝氏体+铁素体+少量M-A岛;随着开冷温度升高,铁素体含量减少,抗拉强度和屈服强度明显提高,屈强比略有增加,伸长率降低,冲击功显著提高;随着终冷温度升高,组织中板条贝氏体转变为粒状贝氏体,M-A岛尺寸和含量增加,抗拉强度和屈服强度降低,屈强比显著降低,冲击功先提高后略有降低;随着冷却速率提高,铁素体含量减少,贝氏体板条细化,抗拉强度逐渐升高,屈服强度先升高后降低,屈强比小幅波动,伸长率先下降后保持不变,冲击功略有提高。
The test steel was smelted in a vacuum induction furnace. The test steel was rolled into a 12 mm thick steel plate by different controlled rolling and ultra-fast cooling processes. The microstructure of the steel plate was observed and the tensile and impact properties were tested. The results show that the microstructure of the test steel is bainite + ferrite + a little MA island. With the increase of cold temperature, the ferrite content decreases, the tensile strength and yield strength increase obviously, but the yield ratio increases slightly, The elongation decreases and the impact energy increases significantly. With the increase of the final cooling temperature, the bainite in the microstructure turns into granular bainite, the size and content of MA island increase, the tensile strength and yield strength decrease, and the yield ratio As the cooling rate increases, the ferrite content decreases, the bainite strip becomes thinner, the tensile strength gradually increases, the yield strength increases first and then decreases, and the yield ratio Slight fluctuations, the elongation decreased after the first to remain unchanged, impact energy slightly improved.