Ti-B微合金化焊缝金属的韧化机制

针对 5 0 0～ 6 0 0MPa低合金高强度钢的韧化问题 ,研究了夹杂物对Ti-B微合金化焊缝金属针状铁素体形成的影响。钢中的非金属夹杂物 ,对促进晶内针状铁素体的形成 ,提高焊缝金属韧性有显著的作用。通过电镜分析 ,探讨了夹杂物的类型、成分对针状铁素体形成的作用。结果表明 ,Ti、Mn、Al、Si的复合氧化物夹杂可有效地促进针状铁素体形核 ,而MnO·SiO2 夹杂和MnS夹杂对针状铁素体形核作用不大。夹杂物对针状铁素体形核的主要用是 ,在夹杂物周围能形成一个塑性畸变区 ,这个由夹杂物与母相热膨胀系数差引起的塑性区 ,对针状铁素体的形成有一定作用

Mechanism on toughness improvement of Ti-B containing weld metal

The acicular ferrite formation mechanism in 500-600 MPa high-strength low-alloy steel weld metal was investigated. The role of inclusions on the nucleation of acicular ferrite in Ti-B containing weld metal was discussed. The influence of inclusions compositions and types on the nucleation of acicular ferrite is studied by electron microscope techniques and X-ray energy dispersive analysis. The results suggest that Ti, Mn, Al, Si oxides provide active nucleation sites for acicular ferrite,but MnS and MnO·SiO₂ are not a effective for fine acicular ferrite nucleation. The scanning electron micrographs show that there is a shadow zone surrounded the inclusion. It is a plastic zone of matrix. It seems to be more effective for the formation of acicular ferrite.