| Title |
A Study on the Mechanical Properties of Duplex Stainless Steel Weldment According to Mo Contents |
| Authors |
(Seong Han Bae); (Hee Dae Lim); (Won Jung Jung); (Woong Gil); (Eon Chan Jeon); (Sung Geun Lee); (Hyo Jong Lee); (In Soo Kim); (Hae Woo Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2012.50.9.645 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
metal; welding; mechanical properties; scanning electron microscopy; SEM; impact test |
| Abstract |
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. |