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采用金相显微镜和QUANTA-400型环境扫描电镜,对4145H钢锻轧组织和稀土夹杂物进行观察。结果表明,在钢材纵向上分布着明显铁素体+珠光体带状组织,造成带状组织的原因是枝晶偏析。采用高温扩散退火的方法,将温度升高到1250℃保温20 h,当温度降低到600℃时出炉空冷,即可完全消除带状组织,且随着稀土含量的增加铁素体逐渐减少,甚至消失。
Microstructure and rare earth inclusions of 4145H steel were observed by metallographic microscope and QUANTA-400 environmental scanning electron microscope. The results show that there are obvious ferrite + pearlite bands distributed in the longitudinal direction of the steel, and the reason of ribbon structure is dendritic segregation. High temperature diffusion annealing method, the temperature was raised to 1250 ℃ insulation 20 h, when the temperature dropped to 600 ℃ when baked air cooling, to completely eliminate the ribbon structure, and with the increase of the content of rare earth ferrite decreased, or even disappear.