夹杂物对海工用H型钢冲击韧性影响及分析

针对400 MPa级海洋工程用热轧H型钢-40 ℃条件下冲击试验出现单值偏低的现象,研究了夹杂物种类、形貌及尺寸对低温冲击韧性的影响。采用光学显微镜,扫描电镜对同组3个试样进行了显微组织、夹杂物分布、种类及尺寸对比观察。结果表明,夹杂物对海工用H型钢的冲击韧性具有一定的影响,在缺口附近聚集分布的夹杂物使冲击韧性降低。因此,降低夹杂物数量,改变夹杂物尺寸是提高冲击韧性的途径之一;工业生产中采取降低钢水中含氧量、夹杂物改质、增加吹气时间及保护浇铸等措施能够有效去除钢中的夹杂物。

Effect of inclusions on impact toughness of H-shaped steel for marine engineering

Aiming at the phenomenon of single low value in impact test of 400 MPa grade hot rolled H-shaped steel at -40 ℃, the effects of inclusion species, morphology and size on the low-temperature impact toughness were studied. The microstructures, inclusion distribution, types and sizes of the three samples in the same group were observed by optical microscopy and scanning electron microscopy. The results show that the inclusions have a certain effect on the impact toughness of H-shaped steel, and the inclusions clustered near the notch reduce the impact toughness. Therefore, reducing the number of inclusions and changing the size of inclusions is one of the ways to improve the impact toughness. In industrial production, measures such as reducing the oxygen content in the molten steel, modifying the inclusions, increasing the blowing time and protecting the casting can effectively reduce the inclusions in the steel.