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采用慢应变速率拉神(SSRT)实验和SEM研究了SRB对X100管线钢在典型的西北盐渍土壤(库尔勒土壤模拟溶液)中应力腐蚀开裂行为的影响。结果表明,X100管线钢母材和焊缝在无菌的库尔勒土壤模拟溶液中具有较高的SCC敏感性,其断口模式为穿晶+沿晶SCC混合断裂;X100管线钢母材和焊缝在含有SRB的库尔勒土壤模拟溶液中的SCC敏感性低于无菌时的,其断口模式为穿晶SCC断裂,说明SRB的存在抑制了X100管线钢的脆变,致使X100管线钢的SCC敏感性降低,这可能是由于SRB能在X100管线钢表面快速繁殖并形成生物膜,该生物膜随时间的增加会不断的堆积并变得致密,一定程度上阻隔了活性阴离子Cl-进入X100管线钢基体表面,致使X100管线钢的SCC敏感性减小。
The effect of SRB on the stress corrosion cracking behavior of X100 pipeline steel in typical northwestern saline soils (Korla soil simulating solution) was investigated using slow strain rate pull-out (SSRT) experiments and SEM. The results show that the X100 pipeline steel base metal and weld have high SCC sensitivity in sterile Korla soil simulating solution. The fracture mode of the X100 pipeline steel is mixed fracture of transgranular and intergranular SCC. The SCC sensitivity of SRB-containing Korla soil simulated solution was lower than that of the non-sterile, and the fracture mode was transcrystallization SCC, indicating that SRB inhibited the embrittlement of X100 pipeline steel and decreased the SCC sensitivity of X100 pipeline steel , Which may be due to the ability of SRB to rapidly multiply and form biofilm on the surface of X100 pipeline steel. The biofilm will accumulate and become dense with the increase of time, blocking the active anion Cl- to a certain extent from entering the surface of X100 pipeline steel substrate , Resulting in reduced SCC susceptibility of X100 pipeline steels.