Residual stress analysis of laser spot welding of steel sheets

Abstract

a b s t r a c tExperimental and numerical studies were conducted to characterize laser and resistance spot welds to gain an understanding of load carrying capacity, temperature distributions and residual stress states of different joint geometries used in the automotive industry. Different laser spot weld path geometries are compared with conventional resistance spot welds to find the residual stress distributions in each. It was found out that the weld region in laser spot welding is surrounded by a compressive region which has higher compressive stress values and larger size than that of resistance spot welds. Simulations showed good agreement with experimental temperature distributions, and were able to qualitatively predict the residual stress distributions in each of the weld geometries. The thermal history at known failure locations within the welds and the influence of the weld geometries on cooling rate are also discussed.

Depth-Resolved Residual Stress Analysis with Conical Slits for High-Energy X-Rays

“…3. They confirmed the validity of the used finite element model simulation [10]. However, the spatial resolution of 1.5 mm is probably insufficient to reveal details of the residual stress distribution in the complex weld geometry in lateral directions.…”

“…Start and end points of laser welds are often prone to failure due to low penetration and imperfections or impurities as a result of keyhole collapse. Therefore, a new geometry had been developed for laser spot welds (LSW), where both start and end points are protected from external forces by a layer of continuously welded material [10]. This geometry was referred to as "pretzel" (Fig.…”

“…Neutron diffraction had been used before for determining residual stresses (RS) in the two sheets of the overlap joints separately using a cubic gauge volume with a size of about 1.5 mm [10]. Residual strains had been determined in three orthogonal directions.…”

Study on fibre laser spot welding of TRIP980 steel

“…Laser spot welding, without requiring a lot of auxiliary equipment, can rapidly adapt to the changes in products to meet market demands. [5][6][7][8][9][10] All these characteristics make laser spot welding replace conventional resistance spot welding and riveting processes in the industrial productions, including electronic components, aerospace, automobile, shipbuilding, etc. 2,3,11 The majority of previous studies concerning laser spot welding has focused on the welding of tiny components with use of high frequency and low power pulsed laser equipment.…”

Thermomechanical Modeling of Laser Spot Welded Solar Absorbers

“…Recently, a number of numeri cal models have been developed to study thermal and mechanical phenomena during laser processes. These models were used to evaluate temperature distributions and to predict the weld pool shape, the melting zone, and the dimensions of the HAZ [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], In some studies, a fully or sequentially coupled thermal-stress analysis was also carried out to determine the thermal deformations-distortions and the residual stress-strain fields [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. Most of these investigations are limited to problems associated with continuous or single spot laser welding in butt-, lap-, or T-joint specimens; the mechanical effects of LSW in manufactur ing processes of large industrial structures, such as solar absorb ers, have not been investigated so far.…”