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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．
By changing the heavy rare earth content in the electrode coating, different contents of heavy rare earth elements are transferred to the weld to improve the mechanical properties of the weld. The results show that the microstructure of the weld metal can be purified and metamorphosed by adding a trace amount of rare earth elements to the weld metal. At the same time, due to the refinement and spheroidization of inclusions in the weld metal by rare earth elements, The amount of acicular ferrite in the weld increased the low temperature impact toughness of the weld. The transmission electron microscopy showed that alloying elements in the weld could form acicular iron as long as they could form fine and insoluble non-metallic inclusions. The nucleus of the body. Acicular ferrite composed of many substructures, which is equivalent to further refine the grain, is to improve the low temperature impact toughness of the weld metal micro-reasons.