Investigation on the influence of nitrogen in process atmospheres on the corrosion behavior of brazed stainless steel joints

20th Chemnitz Seminar on Materials Engineering - 20. Werkstofftechnisches Kolloquium

Fedorov, V.^1 ; Uhlig, T.^1 ; Wagner, G.^1 ; Langohr, A.^2 ; Holländer, U.^2

Institute of Materials Science and Engineering, Chemnitz University of Technology, Germany^1

Institute of Materials Science, Leibniz University Hannover, Germany^2

关键词: Air conditioning technologies;    Carrier gas hot extractions;    Continuous furnaces;    Corrosion and oxidation;    Corrosion measurements;    Corrosion potentials;    Nitrogen enrichment;    Stainless steel joints;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/373/1/012022/pdf
DOI  :  10.1088/1757-899X/373/1/012022

来源: IOP

【 摘 要 】

Brazing of stainless steels is commonly carried out using nickel-based brazing fillers, which provide a high corrosion and oxidation resistance of the resulting joints. These brazed stainless steel joints are mostly used for manufacturing of heat exchangers for energy and air conditioning technologies. The joints of the study were produced at temperatures of 1000 °C, 1125 °C and 1150 °C in vacuum furnaces or continuous furnaces. In both cases, the parts interact with process gases like nitrogen within the brazing process, especially during cooling. The amount of nitrogen in the braze metal as well as in the base material was determined by the carrier gas hot extraction technique. The occurring diffusion of nitrogen into the braze metal and the base material causes a shift in the corrosion potentials. In this work, the influence of the nitrogen enrichment on the corrosion behavior was investigated using a capillary microcell. The corrosion measurements were carried out on the braze metal and the base material. The results of samples, brazed with and without the influence of nitrogen, were compared.