Heat and mass transfer in laser dissimilar welding of stainless steel and nickel

Abstract

a b s t r a c tLaser spot welding of stainless steel-nickel dissimilar couple has been studied experimentally and numerically. A three-dimensional heat and mass transfer model is used to simulate the welding process, based on the solution of the equations of mass, momentum, energy conservation and solute transport in weld pool. The calculated fusion zone geometry and element distributions are in good agreement with the corresponding experimental results. The role of fluid flow on temperature field and its evolution is analyzed by comparing two cases with and without considering convection. Temperature fields far away from the weld pool are quite similar, but exhibit large difference close to the heat source. During the early stage after formation of weld pool, the distribution of element Fe in weld pool is non-uniform, due to insufficient time for mixing. The speed for mass transport is the highest during the initial stage of weld pool formation and it decreases with time. Both heat and mass transport are significantly influenced by convection during laser spot welding of stainless steel and nickel.

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

“…Figure 12 plots the top-surface temperature coefficient of surface tension in air atmosphere. In comparison to a constant value usually used [14,42,43], the temperature coefficient of the surface tension in the present study of air shielding decreases as temperature increases. It reaches a minimum value and becomes negative at the center of the weld pool.…”

“…Fluid dynamics in the laser-induced weld pool has been considered to be the important mechanism for the heat transport [14,[26][27][28][29][30]. Buoyancy effect and Marangoni effect due to temperature variation have been considered to be the driving forces for fluid flow.…”

“…For friction welding, the low efficiency and welding defects are concerning. Alternatively, highpower-density laser has attracted enormous research interest and found its wide application in a broad branch of manufacturing areas including selective laser sintering and three-dimensional printing [1][2][3][4][5][6], surface nanostructuring [7][8][9][10][11][12], multimaterial joining and integration [13][14][15][16][17], material removal [18,19], and mechanical/optical property enhancements [20][21][22][23]. Characteristics, such as contact-free processing, good flexibility and tunablity, high efficiency, and throughput, make laser a feasible route for welding of 42CrMo [24,25].…”

Numerical simulation of thermal behavior and multicomponent mass transfer in direct laser deposition of Co-base alloy on steel

“…Due to the difference in chemical composition and thermophysical property of substrate and added material, a great deal of defects, involving the non-fusion owing to insufficient heat transfer, the formation of brittle intermetallic compound and low melting point eutectics owing to inappropriate solute transport, all make the deposited layer prone to crack and failure [9,4,10]. Selecting appropriate composition of powder material and thermophysical property is an approach to overcome the problem and obtain ideal deposited layer properties.…”

Investigation of temperature and residual stresses field of submerged arc welding by finite element method and experiments

“…Several numerical [5][6][7][8][9][10][11][12][13][14][15][16][17] and experimental investigations [1,2,[18][19][20][21][22] of arc welding have been reported by various researchers. Rosenthal [23] first proposed a mathematical model of a moving heat source under the assumption of quasi-steady state; however, as many researchers have discussed, Rosenthal's analysis (that assumes either a point, line, or plane source of heat) has major error for temperatures in or near the fusion and heat-affected zones [24].…”