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利用Gleeble-3800热模拟试验机,采用热膨胀法结合硬度测试研究了含硼和不含硼两种低碳钢的连续冷却转变过程,通过光学显微镜、扫描电镜分析了不同冷速下两种钢的组织转变。结果表明,不含硼钢未得到全部贝氏体组织,含硼钢可在相当大的冷速范围内得到全部贝氏体组织,且可细化显微组织;含硼钢中冷速大于5℃/s时出现板条贝氏体,而不含硼钢在整个试验冷速范围内均无板条贝氏体出现;含硼钢的硬度明显高于不含硼钢相同冷速下的硬度值,且随着冷却速度的增加相同冷速下含硼钢与无硼钢硬度值的差明显变大。
Using Gleeble-3800 thermal simulation testing machine, the continuous cooling transformation process of boron-containing and non-boron-containing low-carbon steel was studied by thermal expansion method and hardness test. By optical microscope and scanning electron microscope, Organizational change. The results show that the bainitic steel is not obtained without boron steel, the bainitic steel can be obtained in a wide range of cooling rate and the microstructure can be refined. When the cooling rate is higher than 5 ℃ / s, the lath bainite appears, while the non-boron steel does not appear lath bainite throughout the cooling rate range; the hardness of boron-containing steels is obviously higher than that of boron-free steels at the same cooling rate Value, and with the cooling rate increases with the same cooling rate boron-containing steel and boron-free steel hardness difference significantly larger.