Diffusion-based analytical modeling of brazing stainless steel with BNi-2

An analytical modeling coupled with experimental data has been used to study the kinetics of dissolution and isothermal solidification at the brazing temperature for brazing SS304/BNi-2/SS304 joint based on the diffusion theory. A set of coupled finite differential equations have been presented to accurately track the diffusion-controlled motion of solid/liquid interface in this paper. The diffusion coefficient, used in the analytical modeling, of boron into the stainless steel during isothermal solidification has been mathematically determined together with experimental data from brazing the wedge-shaped joint of SS304/ BNi-2/SS304. The results of three aspects including the solute concentration evolution, the maximum half-liquid width and the time to complete isothermal solidification can be obtained. Their effects on the brazing process are also investigated.