双相不锈钢钢管性能控制的新途径——亚稳界分解热处理(上)

A New Way for Duplex Stainless Steel Pipe Performance Control——Spinodal Decomposition Heat Treatment(Ⅰ)

475℃脆化限定了铁素体不锈钢管及双相不锈钢管只能在280℃以下温度服役,富Cr的α′铁素体析出并最终造成贫Cr的α″铁素体强度和硬度增加,但耐蚀性劣化是公认的事实。然而近期研究揭示,280~500℃短时时效并不损害双相不锈钢铁素体区的耐蚀性,这种称为亚稳界分解热处理的工艺可能成为既达到强化又优化耐蚀性的附加热处理方法。简要介绍了高Cr铁素体不锈钢的475℃脆化以及析出分解和亚稳界分解的本质区别,同时讨论了双相不锈钢亚稳界分解热处理的原理及其作为一种新型合金制造方法的应用。

Ferrite stainless steel pipe and ferrite-austenite duplex stainless steel pipe could only service under 280 ℃ because of embrittlement at 475 ℃, It was a fact generally recognized that Cr-rich α′-ferrite precipitation finely resulted in increasing strength and hardness and decreasing corrosion resistance of Cr-depleted α″-ferrite. However recent investigation revealed that the short-term aging heat treatments at 280~500 ℃ may not decrease the corrosion resistance of duplex stainless steels ferrite region, and it was called spinodal decomposition heat treatment that would be a new additional treatment method to improve strength and hardness and optimize corrosion resistance. The essential difference between Cr-rich ferrite stainless steel embrittlement at 475 ℃, precipitation decomposition and spinodal decomposition were introduced, and the principle of spinodal decomposition and the application as a manufacturing method for new alloys had also been discussed.