稀土元素对低合金高强度钢焊缝机械性能的影响

Effect of rear earth on LAHS weld mechanical properties

通过改变焊条药皮中的重稀土含量，向焊缝过渡不同含量的重稀土元素以提高焊缝的机械性能．研究结果表明，通过向焊缝金属过渡微量的稀土元素，可以对焊缝金属起着净化和变质的作用，同时由于稀土元素对焊缝金属中的夹杂物的细化、球化作用，增加了焊缝中针状铁素体的数量，提高了焊缝的低温冲击韧性，通过透射电镜观察，发现焊缝中合金元素只要能形成细小、难溶的非金属夹杂物，均能成为针状铁素体的形核核心．针状铁素体由许多亚结构组成，这相当于进一步细化了晶粒，是提高焊缝金属低温冲击韧性的微观原因．

It can improve the LAHS weld mechanical properties by transferring suitable amount of rare earth elements of the changed electrode coating. The weld metal can be purified and modified by transferring suitable amount of rare earth elements and inclusions in weld metal can be refined and made globular by transferring suitable amount of rare earth elements. The weld alloy elements can be the nucleating centers of acicular ferrite as long as they can form fine non-metallic inclusions which are difficult to dissolve as indicated by the investigation of TEM. Acicular ferrite is consisted of a lot of substructure, and the microstructure can improve the low temperature toughness of weld metal.