Effect of holding time on vacuum brazing for a stainless steel plate–fin structure
2009; Elsevier BV; Volume: 31; Issue: 4 Linguagem: Inglês
10.1016/j.matdes.2009.11.001
ISSN0261-3069
AutoresWenchun Jiang, Jianming Gong, S.T. Tu,
Tópico(s)Microstructure and Mechanical Properties of Steels
ResumoThis paper presents a vacuum brazing of 304 stainless steel plate–fin structures with nickel-based BNi-2 filler metal. The effect of brazing holding time on tensile strength and microstructure has been investigated, aiming to obtain the optimal brazing holding time. The microstructure in brazing joint consists of diffusion-affected zone (DAZ), interface reaction zone (IRZ), isothermally solidified zone (ISZ) and athermally solidified zone (ASZ). The structure in the fillet is composed of solid solution, nickel silicon, nickel boron compound and a mixture with nickel silicon and nickel boron. The tensile strength increases along with the increase of holding time, but decreases when the holding time is over 25 min. A maximum tensile strength of 65.1 MPa is obtained with 25 min holding time. Too short holding time will make boron diffuse insufficiently and generate a great deal of brittle boride components, and too long holding time will make the base metal dissolve into the filler metal excessively and creates more corrosion voids.
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