SRB作用下X100管线钢在酸性土壤环境中的应力腐蚀开裂行为

Stress Corrosion Cracking of X100 Pipeline Steel in Acid Soil Medium with SRB

采用慢应变速率拉神(SSRT)实验和SEM研究了SRB对X100管线钢在典型的酸性土壤(鹰潭土壤模拟溶液)中应力腐蚀开裂行为的影响。结果表明,X100钢母材和焊缝在无菌的鹰潭土壤模拟溶液中的SCC敏感性高于有菌时的,X100钢母材和焊缝在无菌和有菌酸性土壤中的断裂模式均为穿晶SCC断裂,说明SRB的存在抑制了X100钢的脆变,导致X100钢的SCC敏感性降低,这可能是由于SRB能在X100钢表面快速生长繁殖并形成生物膜,该生物膜随时间的增加会不断的堆积并变得致密,一定程度上阻隔了腐蚀性Cl^-进入钢基体表面,致使X100钢的SCC敏感性减小。

The effect of sulfate reducing bacteria （SRB） on stress corrosion cracking （SCC） behav- ior of X 100 pipeline steel was investigated in artificial solution, which simulated the acid soil medi- um in the area of Yingtan at the Southeast China by means of slow strain rate test （SSRT） and scan- ning electron microscope （SEM）. The results show that X100 pipeline steel has higher SCC suscep- tibility in the sterile artificial solution than that with SRB. The failure mode is transgranular crack- ing in both the two solutions. These results suggest that SRB inhibits the brittleness and reduces the SCC susceptibility of X100 pipeline steel, which may be ascribed to that SRB can breed rapidly and form a compact biofilm on X100 pipeline steel surface, then partly block the migration of cor- rosive C1- onto the X100 steel surface.