钢板成分及热处理工艺对中Cr钢耐CO2腐蚀性能的影响

为了研究不同Cr含量及热处理工艺对钢板耐CO2腐蚀性能的影响，采用挂片失重法结合金相和EBSD分析，研究了Cr含量以及不同热处理工艺对低C、中Cr钢在CO2驱油服役环境下的腐蚀性能的影响，并分析了几种Cr含量钢的可焊接性。试验结果显示，在当w（Cr）=3%～9%时，随着Cr含量的提升，试样的耐均匀腐蚀能力逐步增强；其中轧态的腐蚀速率从0.243 mm/a降低到0.087 mm/a，降低了64%；在一定热处理工艺下，几种不同Cr含量的钢种都具有较好的焊接性。研究表明，由于Cr含量的提升使得钢的基体表面形成更加致密的保护膜，阻碍了腐蚀的进一步发展；对于Cr7.5钢，轧态下的耐均匀腐蚀能力最强，回火态的其次，正火态最差，耐蚀性能的差异是由于轧态组织中单位面积内晶界的长度最小、而正火态晶粒长度最大所造成的。

Effect of Composition and Heat Treatment Process on CO2 Corrosion Resistance of Cr Steel

In order to study the effects of different compositions and heat treatment process on CO2 corrosion resistance of Cr steel, using the weight loss method combined with metallographic and EBSD analysis, the corrosion properties of Cr steel samples with low C under different conditions of compositions and heat treatment process in CO2 flooding service environment were studied, and weldabilities of different Cr steel was analyzed. The results showed that the corrosion resistance of the samples increases with the increase of Cr content at the range of 3%～9% Cr; the corrosion rate of rolling was reduced from 0.243 mm/a to 0.087 mm/a, which decreased of 64%; different contents of Cr steel all had good welding ability. The study indicated that the reason was that the increase of Cr contents made the substrate surface form a more dense protective film to hinder the further development of corrosion; for Cr7.5 steel, the steel under rolling got the strongest corrosion resistance, then under tempering, and the last under normalizing; in such conditions, differences in corrosion resistance were due to the length of the grain boundary in the as-rolled microstructure was the smallest, and in the normalized state was the largest.