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Vol.50, No.9, 645 ~ 652, 2012
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| Title |
| A Study on the Mechanical Properties of Duplex Stainless Steel Weldment According to Mo Contents |
| 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 |
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| 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. |
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| Key Words |
| metal, welding, mechanical properties, scanning electron microscopy, SEM, impact test |
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