EFFECTS OF N CONTENT ON MICROSTRUCTURE AND PROPERTIES OF 29Cr CASTING SUPER DUPLEX STAINLESS STEEL

作者：Xiang Hongliang^*; Huang Weilin; Liu Dong; He Fushan

来源：Acta Metallurgica Sinica, 2010, 46(3): 304-310.

DOI：10.3724/SP.J.1037.2010.00304

• 29Cr super duplex stainless steel
• N content
• tensile strength
• elongation
• polarization curve
• passive film

Microstructures, mechanical properties and corrosion resistances of 29Cr super duplex stainless steel (SDSS) with N contents of 0.11%. 0.26% and 0.42% have been investigated by XRD, SEM, EDS. electrochemical workstation and XPS. The results show that with increasing N content the distribution of Cr becomes homogeneous. the amount of gamma phase increases according to a linear relationship of phi(gamma) = 60 x w(N)+21.97, and the tensile strength and elongation of the steel are improved according to the relationships of sigma(b) = 318.33 x root w(N)+626.3 and delta = 60 x w(N)+10.83, respectively, due to the roles of solution strengthening and reducing (Mn, Cr)S precipitation. In the process of seawater corrosion; a phase in the steel would be corroded first, N can form NH4+ and NO3- to promote the re passivation effect of passive film; and Mo can form MoO42- to improve the stability of passivated layer and strengthen the corrosion resistance of the steel. The higher the N content, the lower the corrosion current density and the better the corrosion resistance for the steel.

• 出版日期2010-3-11
• 单位福州大学