σ相对S32760超级双相不锈钢组织和性能的影响  

Influence of σ phases on the microstructure and properties of S32760 super duplex stainless steel

作　　者：李国平[1,2] 裴海祥[1] 李建春[1] 张寿禄[1] 

机构地区：[1]山西太钢不锈钢股份有限公司,太原030003 [2]太钢先进不锈钢材料国家重点实验室,太原030003

出　　处：《工程科学学报》2016年第3期364-370,共7页Chinese Journal of Engineering

基　　金：国家科技支撑计划资助项目(2012BAE04B01);国家高技术研究发展计划资助项目(2015AA034301)

摘　　要：通过对含W的S32760超级双相不锈钢不同温度时效热处理研究σ相的析出行为.用扫描电镜和透射电镜分析σ相的形貌和化学组成,并研究σ相对力学性能和耐腐蚀性能的影响.在850~1000℃之间,实验钢析出大量由Fe-Cr-Mo-W组成的具有正方结构的σ相,钢板强度和硬度高,塑性差,延伸率低于4%;1050℃时仍存在少量析出,虽然延伸率大幅度提高至31.1%,但冲击韧性离散度高,冲击功偏低;直至1080℃,σ相才能完全溶解至基体中,抗拉强度为640MPa,延伸率为35.5%,纵、横向冲击功平均值分别达到217J和110J.随时效热处理温度升高,点蚀电位提高,点蚀失重率不断下降,1080℃热处理的试样点蚀电位高达1246mV.该试样在50℃的3.5%NaCl溶液中腐蚀失重率也仅为0.005~0.007g·m-2·h-1.The precipitation behavior of σ phases in W-containing S32760 super duplex stainless steel was studied by aging treatment experiments. The morphology and chemical composition of the σ phases were investigated by scanning electron microscopy and transmission electron microscopy. The effects of the σ phases on the mechanical properties and corrosion resistance of the stainless steel were analyzed additionally. The σ phases composed of Fe- Cr- Mo- W have a tetragonal structure and abundantly precipitate at850-1000 ℃ in the stainless steel with quite high strength and hardness and extremely poor plasticity,for example,the elongation is lower than 4. 0%. There are still a few of σ phases at 1050 ℃,though the elongation increases to 31. 1%,the values of impact toughness are discrete,and the average impact energy is low. Until 1080 ℃,the σ phases completely dissolve to the matrix. The tensile strength and the elongation are 640 MPa and 35. 5%,and the longitudinal and the transverse impact energies averagely reached to 217 J and 110 J,respectively. As the treatment temperature increasing,the pitting potential（ Eb） improves,and the mass loss rate of pitting corrosion decreases. The pitting potential of the stainless steel treated at 1080 ℃ is up to 1246 m V,while the mass loss rate decreases only to 0. 005-0. 007 g·m- 2·h- 1when being soaked in a 3. 5% Na Cl solution at 50 ℃.

关 键 词：不锈钢 热处理 析出相 微观组织 力学性能 耐腐蚀性 

分 类 号：TG142.71[一般工业技术—材料科学与工程]