Reduction of liquid metal embrittlement in copper-brazed stainless steel joints

19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium

Uhlig, T.^1 ; Fedorov, V.^1 ; Elßner, M.^1 ; Wagner, G.^1 ; Weis, S.^2

Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz

09125, Germany^1

Professur Füge- und Beschichtungstechnik, Institut für Produktionstechnik, Westsächsische Hochschule Zwickau, Zwickau

08012, Germany^2

关键词: Corrosion products;    Degree of deformations;    Electrochemical potential;    Liquid metal embrittlement;    Plate heat exchangers;    Raw material costs;    Stainless steel AISI 316L;    Stainless steel joints;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/181/1/012032/pdf
DOI  :  10.1088/1757-899X/181/1/012032

来源: IOP

【 摘 要 】

Due to its very good formability and the low raw material cost, pure copper in form of foils is commonly used to braze plate heat exchangers made of stainless steel. The difference in the electrochemical potentials of brazing filler and base material leads to corrosion effects in contact with electrolytes. This may lead to leakages, which decrease the reliability of the heat exchanger during service in potable water. The dissolution of the emerging corrosion products of brazing filler and base material induces the migration of heavy metal ions, such as Cu2+and Ni2+, into the potable water. The so-called liquid metal embrittlement, which takes place during the brazing process, may intensify the corrosion. The brazing filler infiltrates the stainless steel along the grain boundaries and causes an embrittlement. This paper deals with the determination of the grain boundary erosion dependent on the degree of deformation and heat treatment of the stainless steel AISI 316L.