Ni,Mo和Cu添加对13Cr不锈钢组织和抗CO2腐蚀性能的影响

摘要

The special 13Cr stainless steel containing different contents of Ni,Mo and Cu was melted by plasma arc furnace using orthogonal experimental method.The microstructure,phase characteristics,electrochemical corrosion,high-temperature and high-pressure immersion corrosion behavior in the oilfield produced solution saturated with CO2 of alloys were investigated.The results indicated that the microstructure of alloy was mainly of martensite and ferrite,which was slightly different with the contents of Ni,Mo and Cu.Ni4Mo1.2Cu1.4alloy exhibited the highest hardness (296.48HV1.0) for the occurrence of high content of martensite.All alloys exhibited the remarkable nature of the passivation effect.The lowest passivation current density 2.99 × 10-6A · cm-2 and highest pitting potential 0.35V (SCE) were found in Ni4Mo1.2Cu1.4 alloy resulted from the stable passive film.The general corrosion rate of alloys at high temperature and high pressure ranged from 0.041mm/a to 0.053mm/a,was lower than the given value 0.076mm/a.An increased in Ni,Mo and Cu content enhanced corrosion potential leading to the reduction of corrosion tendency.The most effective element for improved the corrosion resistance of alloys was Cu.%采用正交实验法,通过等离子电弧炉制备添加不同含量Ni,Mo和Cu元素的13Cr不锈钢,研究合金的微观组织、结构特征以及饱和CO2油田采出液中的腐蚀电化学和高温高压浸泡腐蚀行为.结果表明:合金组织主要为马氏体和铁素体,随Ni,Mo和Cu含量不同而变化;Ni4Mo 1.2Cu14合金中马氏体含量较高,硬度达到296.48HV1.0;所有合金均呈现出明显钝化特征,Ni4 Mo12Cu14合金具有最低的维钝电流密度2.99×10 6A·cm 2和最高的点蚀电位0.35V(SCE),钝化稳定性最高;制备合金在高温高压下的浸泡腐蚀速率为0.041～0.053mm/a,低于0.076mm/a;Ni,Mo和Cu元素加入提高了合金的自腐蚀电位,降低了腐蚀倾向,其中Cu对于改善合金耐蚀性能作用最为突出.