稀土对4145H锻材的组织及夹杂物的影响

Influence of Rare Earth on Microstructure and Inclusions of 4145H Steel

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。

The forging microstructure and inclusions of rare earth of 4145H steel were observed by metallographic microscope aenvironmental and QUANTA-400 environmental SEM. The results show that there is obvious banding structure including ferrite and pearlite in the vertical orientation of the steel. The cause of forming banding structure is dendritic segregation. High temperature diffusion annealing is adopted. Temperature increases to 1250 ℃ and insulation for 20 h, then air cooling. When the temperature decreases to 600 ℃, the banding structure can be completely eliminated.