| Title |
A Study on Microstructure Change and Pitting Corrosion Resistance of Ferritic Stainless Steel Weldment According to Nb Contents |
| Authors |
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) |
| DOI |
https://doi.org/10.3365/KJMM.2014.52.12.995 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
alloys; welding; precipitation; electron backscattering diffraction(EBSD); stainless steel |
| 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. |