摘要
采用慢应变速率试验(SSRT)、扫描电镜(SEM)观察研究了国产X80管线钢焊接接头在0.5mol/LNa2CO3+1mol/LNaHCO3溶液中的应力腐蚀开裂(SCC)敏感性。结果表明,拉伸试样全部断裂在焊缝或热影响区。在所研究的电位区间,拉伸试样随着外加电位正向增加,断面收缩率、断裂时间和断后伸长率增加,而断口部位的裂纹平均扩展速率减小,SCC敏感性降低。试样断口形貌在阴极电位条件下呈准解理断裂,在自腐蚀电位和阳极电位条件下,焊缝试样断口主要是韧性断裂。应力腐蚀机理可以用阳极溶解理论和氢致破裂来解释。
The susceptibility to stress corrosion cracking (SCC) of the welded joint of X80 pipeline steel in solution of 0.5 mol/L Na2CO3 and 1mol/L NaHCO3 was investigated by means of slow strain rate testing (SSRT) and scanning electron microscope. The results showed that all tensile test specimens cracked in welded joint and heat affected zone (HAZ). The general tendency in the studied potential range was that with positive increasing of potential, reduction in area, fracture time and elongation of specimens increased, and mean crack growth rate of SCC and the susceptibility to SCC decreased. At cathodic potentials, obvious quasi-cleavage fracture was observed in the fracture area of specimens. At open circuit potential and anodic potential, ductile fracture was the common fracture pattern. The mechanism of the stress corrosion could be explained with anodic solution theory and hydrogen induced cracking.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2007年第7期85-88,共4页
Transactions of The China Welding Institution
