干湿交替与水饱和条件下轮南壤土中X80钢焊管的腐蚀行为

Corrosion Behavior of Weld Pipe of X80 Steel in Lunnan Loam under Wet/Dry Alternation and Water Saturation Conditions

选择取自轮南油田的壤土作为腐蚀介质,在干湿交替和水饱和条件下对X80钢焊管进行室内模拟腐蚀试验,对比研究了母材和焊缝试样的腐蚀速率、腐蚀形貌和腐蚀产物。结果表明:试验钢在干湿交替条件下的腐蚀速率是水饱和条件下的2~48倍,且母材比焊缝更耐蚀;母材和焊缝试样在水饱和环境下均以轻微的全面腐蚀为主,在干湿交替条件下呈现土壤板结形貌,存在大量腐蚀坑;水饱和条件下,母材表面腐蚀产物内层薄且致密,外层分散出现龟裂,焊缝表面腐蚀产物内层已出现龟裂;干湿交替条件下,母材和焊缝表面腐蚀产物均存在裂缝。

With loam taken from Lunnan Oilfield as corrosion medium, indoor simulated corrosion test was carried out on X80 steel weld pipe under wet/dry alternation and water saturation conditions. The corrosion rate, corrosion morphology and corrosion products of the base metal and weld samples were compared and studied. The results show that the corrosion rate of the test steel under wet/dry alternation condition was 2-48 times that under water saturation condition, and the base matal had better corrosion resistant than the weld. The base matal and weld samples were mainly corroded slightly and completely under water saturation condition. The soil plate morphology was presented under wet/dry alternation condition and there were a lot of corrosion pits. Under water saturation condition, the inner layer of corrosion products on the surface of base metal was thin and dense, the outer layer of corrosion products was dispersed and cracked. The inner layer of corrosion products on the surface of weld had crazing. Under wet/dry alternation condition, there were cracks on corrosion products on the surface of base metal and weld.