A Study on the Mechanical Properties of Duplex Stainless Steel Weldment According to Mo Contents

• Published in: Korean Journal of Metals and Materials Vol. 50; no. 9; pp. 645 - 651
• Main Authors: Lee, Hae Woo, Bae, Seong Han, Lim, Hee Dae, Jung, Won Jung, Sil, Woong, Jeon, Eon Chan, Lee, Sung Geun, Lee, Hyo Jong, Kim, In Soo
• Format: Journal Article
• Language: English
• Published: 대한금속·재료학회 01.09.2012
• Subjects: 재료공학
• ISSN: 1738-8228; 2288-8241
• DOI: 10.3365/KJMM.2012.50.9.645

This study investigated changes in phase fraction caused by the addition of Mo, as well as the subsequent behaviour of N and its effect on the mechanical properties of welded 24Cr-N duplex stainless steel weld metals. Filler metal was produced by fixing the contents of Cr, Ni, N, and Mn while adjusting the Mo content to 1.4, 2.5, 3.5 wt%. The delta ferrite fraction increased as the Mo content increased. In contrast, the γ fraction decreased and changed from a round to an acicular shape. Secondary austenite (γ’) was observed in all specimens in a refined form, but it decreased as the Mo content increased to the extent that it was nearly impossible to find any secondary austenite at 3.5 wt% Mo. Both tensile and yield strengths increased with the addition of Mo. In contrast, the highest value of ductility was observed at 1.41 wt% Mo. At all temperatures, impact energy absorption showed the lowest value at 3.5 wt% Mo, at which the amount of -ferrite was greatest. There was no significant temperature dependence of the impact energy absorption values for any of the specimens. As the fraction of γ phase decreased, the amount of N stacked in the γ phase increased. Consequently, the stacking fault energy decreased, while the hardness of γ increased. KCI Citation Count: 5