The laser welding of thin metal sheets: an integrated keyhole and weld pool model with supporting experiments

Abstract

An integrated mathematical model for laser welding of thin metal sheets under a variety of laser material processing conditions has been developed and tested against the results of experiments. Full account is taken in the model of the interaction of the laser-generated keyhole with the weld pool. Results calculated from the model are found to agree well with experiment for appropriate values of the keyhole radius. The analysis yields values for power absorption in the metal. In a complementary calculation the total absorption of the laser energy is determined from detailed consideration of the inverse Bremsstrahlung absorption in the plasma and Fresnel absorption at the keyhole walls. To test these results, experiments were performed on 1 mm mild steel using a high-speed video camera, which measured the surface dimensions of the melt pool. Processing parameters were varied to study the effect on the melt pool; parameters considered included traverse speed, laser power and shroud gas species. The general shape of the weld pool was found to depend on whether penetration was full, partial or blind; only the results for full penetration were compared with the theory, which is for complete penetration only.

A Review on Melt‐Pool Characteristics in Laser Welding of Metals

“…b [11,31,33,[38][39][40][41]; c [11,[33][34][35][36][37][42][43][44]; d [11,12,31,33,38,41,42,45]; e [30]; f [32,42]; g [42,45]; h [7,8]; i [8]; j [43,46]; k [38,41,47]; l [44,46].…”

“…Ducharme et al [42] presented an integrated model of laser welding, taking into account the conditions in the keyhole as well as in the meltpool, interactively. ese authors investigated the influence of process parameters on the melt-pool shape.…”

Modeling of keyhole dynamics and analysis of energy absorption efficiency based on Fresnel law during deep-penetration laser spot welding

“…For a CO 2 laser and steel workpiece, its widely used value is 0.08. However, it is also modifiable because (a) the keyhole wall is boiling and this could affect the Fresnel absorption and (b) the method used to calculate the Fresnel absorption is approximated, and the use of a large value of e could compensate for the approximations made [17]. This paper suggested the value of e to be 0.2 and showed that the results are acceptable for mild steel and CO 2 laser, compared with experiments.…”

Physico-chemical and mathematical modeling of phase interaction taking place during fusion welding processes

“…The areas of the prediction and optimization of the composition and properties of materials obtained in different technological processes are especially promising [5][6][7][8]21,[24][25][26][27][28][29][30][31][32][33]. Some of the results were obtained from the modeling of the process of the formation of a weld pool [5,30], from the modeling of metal transfer [28,31,32] and weld metal transformations [22,23,27,30], and from the modeling of temperature distribution [25] and electrode melting [24], from metallurgical modeling of the welding [11,26] and diffusion-controlled kinetics of metallurgical processes [6,20,2].…”

“…Some of the results were obtained from the modeling of the process of the formation of a weld pool [5,30], from the modeling of metal transfer [28,31,32] and weld metal transformations [22,23,27,30], and from the modeling of temperature distribution [25] and electrode melting [24], from metallurgical modeling of the welding [11,26] and diffusion-controlled kinetics of metallurgical processes [6,20,2].…”