Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets

Abstract

A numerical model was developed for predicting the bead geometry and microstructure in laser beam welding of 2 mm thickness Inconel 718 sheets. The experiments were carried out with a 1 kW maximum power fiber laser coupled with a galvanometric scanner. Wobble strategy was employed for sweeping 1 mm wide circular areas for creating the weld seams, and a specific tooling was manufactured for supplying protective argon gas during the welding process. The numerical model takes into account both the laser beam absorption and the melt-pool fluid movement along the bead section, resulting in a weld geometry that depends on the process input parameters, such as feed rate and laser power. The microstructure of the beads was also estimated based on the cooling rate of the material. Features such as bead upper and bottom final shapes, weld penetration, and dendritic arm spacing, were numerically and experimentally analyzed and discussed. The results given by the numerical analysis agree with the tests, making the model a robust predictive tool.

A thermal finite element model with efficient computation of surface heat fluxes for directed-energy deposition process and application to laser metal deposition of IN718

“…The clad height in DED process for IN718 was previously calculated with a 75% accuracy [51] which is almost the same with as demonstrated in the current study. Accordingly, Hernando et al predicted the weld pool width and depth of IN718 with 90% and 96% accuracy rates, respectively [60]. The well-correlation of melt-pool dimensions for the numerical and experimental results show the predictive strength of the proposed method to estimate the overall interaction of the laser and the respectively.…”

A Virtual Design of Experiments Method to Evaluate the Effect of Design and Welding Parameters on Weld Quality in Aerospace Applications

“…To date, welding simulations are validated and employed in industrial applications to study macro-level product deformation (distortion) and residual stresses. However, the simulation of other aspects of weld quality such as weld bead geometry, microstructure, and formation of metallurgical discontinuities such as cracks and pores are at a research stage [29][30][31][32][33]. Additional aspects of welding simulation that are under investigation are the effects of welding set-up parameters such as gun-to-workpiece distance and beam incident angle [34,35].…”

Microstructure and tensile-shear behavior of dissimilar resistance spot welds between 2304 duplex stainless steel and Inconel 718 superalloy

“…2,6,8,10,11 Inconel 718, as a nickeland iron-based superalloy, is of high importance among high-temperature alloys and is a precipitate-hardenable alloy. [12][13][14][15] Its microstructure normally comprises nickelbased solid solution, such as γ phase (matrix), twins, and carbides. 12,16,17 The applications of Inconel 718 superalloy are related to the aerospace industry, nuclear industry, power generation, gas turbines, tubing hangers, safety valve systems, heat exchangers, and so on.…”