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Vol.52, No.12, 995 ~ 1003, 2014
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| Title |
| A Study on Microstructure Change and Pitting Corrosion Resistance of Ferritic Stainless Steel Weldment According to Nb Contents |
| 김종민 Jong Min Kim , 신용택 Yong Taek Shin , 이상화 Sang Hwa Lee , 이준희 Jun Hee Lee , 이성룡 Sung Riong Lee , 김순호 Soon Ho Kim , 이해우 Hae Woo Lee |
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| Abstract |
| This paper identified the effects of Nb on microstructure. Also, it has studied on uniform and pitting corrosion resistance in a ferritic stainless steel weld metal of the automobile exhaust system. We fabricated 3 flux cored wires designed with 0-1.0 wt% Nb and performed Flux Cored Arc Welding. We observed the microstructure with the SEM/EDS and EBSD. To evaluate the uniform and pitting corrosion resistance, we performed a potentiodynamic polarization test in 0.2 M H2SO4 and 0.1, 0.3, 0.5 M NaCl. As a result of the tests, we found that as the amount of addition of Nb rose, the amount of Cr-carbide fell. The microstructure became more refined. The specimen with 1.0%Nb added had the highest uniform and pitting corrosion resistance. After the pitting corrosion test, a pit was formed at the grain boundary that has no addition of Nb. In addition, in the specimen with added Nb, pits were formed at the inclusions. |
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| Key Words |
| alloys, welding, precipitation, electron backscattering diffraction(EBSD), stainless steel |
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