Aging Effect on Mechanical Behavior of Duplex Satinless Steel

Effect of alloying on the microstructure and mechanical properties of heat-resisting duplex stainless steel (DSS) for Mg production was investigated in this study. 25Cr-8Ni based DSS’s were cast into rectangular ingots of which the dimension was 350×350×100 mm3 . Nitrogen and Yttrium were added in the range within 0.3 in weight percent. Phase equilibrium was calculated using the FactSage®, thermodynamic software. Hot exposure, high temperature tensile and compression tests were conducted on the ingots at 1230oC, which is operation temperature employed for Mg production by Silico-thermic reduction. The steel with N and Y showed much higher strength than 310S alloy in both tensile and compression tests. By thermal exposition at 1230oC for 200 hrs, hardness of DSS containing N and Y was found to increase. Hot workability of the heat-resisting DSS was evaluated by employing hot rolling at 1230 oC. Hot shortness was observed in the ingot with N and found to disappear after addition of Y.

• Jungho Moon
• Tae Kwon Ha

• Duplex Stainless Steel
• alloying elements
• eutectic carbides
• microstructure
• aging treatment.

[1] L. M. Pidgeon and J. A. King, The vapour pressure of magnesium in the
thermal reduction of MgO by ferrosilicon, Discuss. Faraday Soc., vol. 4, p.
197, 1948.
[2] F. Czerwinski, Magnesium injection molding, Springer, p. 1,.
[3] R. C. Newman and T. Shahrabi, The effect of alloyed nitrogen or
dissolved nitrate ions on the anodic behavior of austenitic stainless steel
in hydrochloric acid, Corrosion Science, vol. 27, p. 827, 1987.
[4] J. I. Bae, S. T. Kim, T. H. Lee, H. Y. Ha, S. I. Kim and Y. H. Park, High
Temperature Precipitation Behavior of High-Nitrogen Duplex Stainless
Steel, Kor. J. Met. Mater., vol. 49, p. 93, 2011.
[5] T. H. Lee, C. S. Oh, C. G. Lee, S. J. Kim and S. Takaki, On the
Crystallographic Features of Cr2N Precipitates in High-Nitrogen
Behavior of the Second Phases during Isothermal Aging at 900℃, Kor. J.
Met. Mater., vol. 42, p. 845, 2004.
[6] T. Ogawa, S. Aoki, T. Sakamoto and T. Zaizen, Weldability of
nitrogeon-containing austenitic stainless steel, Welding Journal, vol. 61,
p. 139, 1982.
[7] Y. C. Lu, R. Bandy, C. R. Clayton and R. C. Newman, Surface
enrichment of nitrogen during passivation of a highly resistant stainless
steel, J. Electrochem. Soc., vol. 130, p. 1774 1983.
[8] M. Ceylan, V. Kuzucu, M. Aksoy, I. Aksoy, M. Kaplan and M. M.
Yildirim, Investigation of the casting microstructure of a Fe-base,
Cr-Ni-Mo duplex alloy, Journal of Materials Processing Technology, vol.
69, p. 238, 1997.
[9] S. K. Kim, J. W. Kim, S. D. Shim and Y. Y. Lee, Solidification and
δ-ferrite Formation of High Alloyed Austenitic Stainless Steel, Kor. J.
Met. Mater., vol. 34, p. 1579, 1996.
[10] S. Hertzman and J. Charles, On the effect of nitrogen on duplex stainless
steels, Revue de Metallurgie, vol. 108, p. 413, 2011.