CLAM钢焊缝在550°C流动的铅铋合金中的腐蚀行为

Corrosion behavior of CLAM steel weld bead in flowing Pb-Bi alloy at 550°C

为了研究中国低活化马氏体(CLAM)钢TIG焊缝在流动的铅铋共晶合金(LBE)中的腐蚀行为,对CLAM钢TIG焊缝及母材在550℃,不同相对流速(1.70,2.31,2.98 m/s)的LBE中进行1 500 h的腐蚀试验.结果表明,腐蚀试样表面均存在双层结构的氧化层,外氧化层由疏松的Fe3O4组成,内氧化层由致密的(Fe, Cr)3O4组成;随着LBE相对流速的增加,提高了CLAM基体材料中的Fe,Cr元素向LBE中的溶解速率和LBE中的O元素向CLAM基体材料中的扩散迁移速率,加剧了试样表面的腐蚀程度,最终导致试样表面氧化层的厚度不断增厚;经过相同条件的腐蚀试验后,CLAM钢焊缝试样的抗腐蚀性能比母材试样低.

In order to study the corrosion behavior of China low activation martensitic (CLAM) steel weld bead with TIG welding in flowing lead bismuth eutectic alloy (LBE), corrosion tests of TIG weld bead and base metal of CLAM steel were conducted in LBE with different relative velocity (1.70, 2.31, 2.98 m/s) at 550 ℃ for 1 500 h. The results indicated that the double-layer oxide layers were observed on the surface of corrosion samples. The outer layer was composed of porous Fe3O4, and the inner layer was composed of compact (Fe, Cr)3O4. With the increase of the relative velocity of LBE, the dissolution rate of Fe and Cr from CLAM metal matrix into the LBE, the diffusion and migration rate of O from LBE into the CLAM metal matrix were improved, which aggravated the corrosion degree of the samples and finally led to the continuous thickening of oxide layer on the sample surface. Under the same corrosion conditions, the corrosion resistance of CLAM steel weld bead was lower than that of the base metal.