Mathematical modelling of convective processes in a weld pool under electric arc surfacing

7th International Conference Radiation-thermal Effects and Processes in Inorganic Materials

材料科学;物理学

Sarychev, V.D.^1 ; Granovskii, A. Yu.^1 ; Nevskii, S.A.^1 ; Konovalov, S.V.^1

Siberian State Industrial University, 42 Kirov Street, Novokuznetsk

654007, Russia^1

关键词: Density-functional methods;    Electromagnetic forces;    Electron distributions;    Flux penetration;    Moving heat sources;    Simultaneous solution;    Temperature coefficient;    Vortex structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/168/1/012039/pdf
DOI  :  10.1088/1757-899X/168/1/012039

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The authors develop the mathematical model of convective processes in a molten pool under electric arc surfacing with flux-cored wire. The model is based on the ideas of how convective flows appear due to temperature gradient and action of electromagnetic forces. Influence of alloying elements in the molten metal was modeled as a non-linear dependence of surface tension upon temperature. Surface tension and its temperature coefficient were calculated according to the electron density functional method with consideration to asymmetric electron distribution at the interface "molten metal / shielding gas". Simultaneous solution of Navier-Stokes and Maxwell equations according to finite elements method with consideration to the moving heat source at the interface showed that there is a multi-vortex structure in the molten metal. This structure gives rise to a downward heat flux which, at the stage of heating, moves from the centre of the pool and stirs it full width. At the cooling stage this flux moves towards the centre of the pool and a single vortex is formed near the symmetry centre. This flux penetration is ∼ 10 mm. Formation of the downward heat flux is determined by sign reversal of the temperature coefficient of surface tension due to the presence of alloying elements.