论文部分内容阅读
通过循环载荷实验,研究了管道涂层剥离条件下,阴极保护电位对X70管线钢在近中性pH值溶液(NS4溶液)中应力腐蚀裂纹萌生的影响.利用SEM观察了距涂层剥离口不同距离处的应力腐蚀裂纹的萌生情况.结果表明,外加-850 mV阴极保护电位时,剥离涂层下样品表面裂纹的萌生程度随距离涂层开裂口长度的增加而逐渐减轻;外加-1000 mV阴极保护电位时,剥离涂层下样品表面裂纹的萌生程度随距离涂层开裂口长度的增加而稍有增加,但缝隙内各个位置的裂纹萌生程度低于-850 mV极化电位下缝隙内部相应位置的裂纹萌生程度;涂层的剥离降低了阴极保护的效果,要达到涂层完整时的阴极保护效果,则需要使阴极保护电位适当负移.
The effect of cathodic protection potential on the stress corrosion cracking initiation of X70 pipeline steel in near-neutral pH solution (NS4 solution) was investigated by cyclic loading experiment, and the effect of cathodic protection potential The results show that the initiation of surface crack initiation decreases with the increase of the length of the crack in the coating when the cathodic protection potential of -850 mV is applied, At the protection of potential, the initiation of crack on the surface of the sample under the peel coating slightly increases with the increase of the length of the crack from the coating, but the crack initiation at each position in the crack is less than -850 mV. Of the crack initiation; coating stripping reduce the effect of cathodic protection, to achieve the integrity of the cathodic protection coating effect, you need to properly negative negative cathodic protection potential shift.