等温温度对K55级低碳微合金钢组织和力学性能的影响

Effects of Isothermal Temperature on Microstructure and Mechanical Properties of K55 Grade Low Carbon Microalloyed Steel

研究了不同等温温度对K55级低碳微合金试验钢显微组织和力学性能的影响。结果表明：随着等温温度的升高,试验钢组织中贝氏体体积分数降低,铁素体晶粒尺寸变大;同时,试验钢强度逐渐降低,塑性、韧性逐渐升高。试验钢等温处理温度为550℃时力学性能最佳,具有最高的强度和良好的塑性、韧性。

The effects of different isothermal temperatures on microstructure and mechanical properties of K55 grade low carbon microalloyed test steel were studied. The results show that, the volume fraction of bainite decreases with the increase of isothermal temperature, and the grain size of ferrite increases. At the same time, the strength of the test steel gradually decreases, and the plasticity and toughness gradually increase. When the isothermal treatment temperature is 550 ℃, the test steel has the best mechanical properties, including the highest strength, good plasticity and toughness.