轻稀土对低合金钢焊缝韧性的影响

在低合金高强钢焊条中，通过药皮过渡轻稀土元素，探讨其对焊缝韧性的影响。结果表明：适量的稀土具有脱氢、脱硫、减少夹杂物数量、净化焊缝组织的作用。稀土的加入，对焊缝组织形成有一定的影响，能抑制侧板条铁素体的转变，促进针状铁素体的形成，由于稀土元素净化作用与细化组织的作用，使低合金钢焊缝金属的韧性得到提高。但加入量过大，造成夹杂增多，晶粒长大，疏松组织，使焊缝的韧性下降。本实验轻稀土加入的合适范围为2％。

Influence of Light Rare Earths on Toughness of Low-Alloy Welded Seam

The influence of light RE on toughness of welded seam and its mechanism were studied by analysis of light rare earth element in the covering of the electrode transition in welding rode of low alloy high strength steel. The experimental results show that proper contents of rare earth elements posess of desulfurizing, dehydrogenating and purifying effect on the welding seam structure. To add rare earth elements will effect on welding seam and, at the same times, the transformation of side batten ferrite is resisted and the pin ferrite structure are promoted. The improved toughness of welding seam is due to the purifying and thinning action of rare earth element. The toughness of the welding seam is decreased when the amount of light rare earth elements is increased excessively, because crystal grain size grows up and the structure looses and the impurities increase. The experimental results show that the suitable range of adding amounts of light rare earth elements is 2%.