固溶温度对特级双相不锈钢组织及耐蚀性能的影响

Effect of Solution Temperature on Microstructure and Corrosion Resistance of Hyper Duplex Stainless Steel

研究了固溶温度对N含量为0．51％和0．72％的特级双相不锈钢组织和耐蚀性的影响，并对比分析了特级双相不锈钢与超级双相不锈钢2906的耐蚀性能。结果表明，N含量为0．51％的特级双相不锈钢在1170～1220℃区间固溶处理时的组织只有α和γ两相组成，而N含量为0．72％的特级双相不锈钢经1170℃固溶处理会析出γ2相，随着固溶温度升高，γ2相消失。N含量为0．51％和0．72％的特级双相不锈钢均在1200℃固溶处理时耐蚀性能最好。特级双相不锈钢中，当组织中存在析出物γ2时，γ2处成为腐蚀薄弱点，最先发生点蚀破坏。N含量为0．72％的特级双相不锈钢耐蚀性优于0．51％的材料，2906超级双相不锈钢耐蚀性最差。

Effects of solution temperature on microstructure and corrosion resistance of hyper duplex stainless steel contained 0.51% and 0.72 % N were investigated. And the corrosion resistance of hyper duplex stainless steel compared with super duplex stailess 2906 were analyzed. The results show that hyper duplex stainless steel containing 0.51% N is composed of ferrite phase and austenite phase with the solution treatment temperature in 1 170~1 220 ℃. γ2 precipitates can be observed in hyper duplex stain- less steel with 0.72%N at 1 170℃. As the solution treatment temperature increased to 1 200 ℃and to 1 220℃, γ2 precipitates are dissolved. Hyper duplex stainless steel containing 0.51%N and 0.72% N exhibits excellent corrosion resistance with the solution treatment temperature of 1 200 ℃. γ2 precipi- tates are susceptible to corrosion. The corrosion resistance of hyper duplex stainless steel with 0.72%N γ2 is superior-to that of ones with 0.51%N , Corrosion resistance of 2906 steel is the worst.