焊条药皮中稀土氧化物向焊缝中过渡机制的研究

通过向焊条药皮中加入稀土氧化物的方法，研究了在焊条药皮中加入不同种类、不同含量的稀土氧化物对焊缝金属低温冲击韧性、显微组织以及扩散氢含量的影响。实验表明，在焊条药皮中添加适量的稀土氧化物可以细化焊缝组织、增加针状铁素体的含量、提高焊缝金属的低温冲击韧性和降低焊缝中扩散氢含量，这是一种经济有效的向熔池中过渡稀土元素的方法，可以在焊接材料中发挥稀土元素的特殊作用。从焊接冶金的角度出发，深入研究了焊条药皮中稀土氧化物向熔池中过渡稀土元素的机理、规律及其影响因素。研究表明，焊条药皮中的稀土氧化物在熔滴的高温阶段可以分解出稀土活性原子并过渡到熔池中，参与焊接冶金反应，对焊接熔池起到进一步脱硫去氧的作用。

Mechanism of Rare Earth Oxide Transferring from Coated Electrode to Welding Pool

The effect of different kinds and different content rare earth oxide added in coated electrode on low temperature notch toughness, weld metal microstructure and diffusible hydrogen was studied. The mechanism and influencing factors of rare earth oxide transferred from coated electrode to welding pool were also discussed. The experiment shows that proper amount rare earth oxide added in coating can refine microstructure, increase ratio of acicular ferrite in the microstructure, enhance low temperature notch toughness and reduce diffusible hydrogen. The study shows that rare earth oxide added in coated electrode can be decomposed into high activity rare earth atoms at high temperature of droplet stage. This activey rare earth atom can be transferred to welding pool and engaged in welding metallurgy reaction. Therefore, the method of adding rare earth oxide in coating to transfer rare earth element is an economical and effective method. Using this method, we can make full use of the beneficial effect of rare earth oxide in welding material.