0.9强度比异种钢接头的氢脆性能

Hydrogen Embrittlement of Dissimilar Steel Welded Joints with 0.9 Strength Ratio

在海水环境中,为探索新型异种钢接头的氢脆性能,采用金相试验、氢渗透试验、动态充氢拉伸试验研究了该材料的氢渗透行为及氢脆敏感性,并利用了扫描电镜观察断口组织形貌。结果表明:焊接接头焊缝区氢的溶解度位于两母材之间,与其致密的针状铁素体组织有关;靠近低强度一侧母材的热影响区氢的有效扩散系数相对较小、氢溶解度较大,具有明显的吸氢倾向,与其区域金相显微组织粗大、缺陷较多有关。动态充氢拉伸试验结果表明:随着极化电位的负移,异种钢焊接件的断口延伸率和断面收缩率逐渐减小,形貌特征由塑性向解理断裂方向转变,氢脆敏感性增强;当极化电位达到约-950mV时,氢脆现象显著,断裂位置在靠近熔合线的焊缝区。

To explore the hydrogen embrittlement of new dissimilar steel welded joints in seawater,the hydrogen permeation behavior and hydrogen embrittlement sensitivity of the material were studied by me. tallographic test,hydrogen permeation test and dynamic hydrogen stretching test,and the fracture mor. phology was observed with SEM. The results show that the solubility of hydrogen in weld area of weld joint is between two base metal and its compact acicular ferrite structure. The effective diffusion coeffi. cient of hydrogen is relatively small and the hydrogen solubility is large in HAZ near the side of low strength steel,which has obvious tendency of hydrogen absorption. And it is related to the large size and many defects of the metallographic microstructure of HAZ. The results of dynamic hydrogen stretching test showed that the fracture elongation and the section shrinkage of the dissimilar steel weldments gradu. ally decreased with the negative shift of the polarization potential,and the fracture morphology gradually changes from plastic fracture to cleavage fracture direction,and the sensitivity of hydrogen embrittle. ment increases. When the polarization potential was about -950 mV,the hydrogen embrittlement phe. nomenon was obvious,and the fracture location was near the fusion line.