Study of Explosive Welding of A6061/sus821l1 Using Interlayers With Different Thicknesses and the Air Shockwave Between Plates

In this work, interlayers with different thickness were used to weld A6061 aluminum alloy and SUS 821L1 duplex stainless steel. The results indicated that the interlayer thickness had a significant effect on the welding. The influence of the air shock wave between the plates on the welding results was examined. The fluid-Solid coupling finite element method was used to simulate the movement of the interlayer under the action of the air shock wave. The smoothed particle hydrodynamics method was used to simulate the oblique impact process of the plates, and the unwelded samples were analyzed using the simulation results. In the analysis of weldability window, the influence of the interlayer on the upper and lower limits was examined.

Sequential coupling of electromagnetic–structural simulation for compression welding of tubular jobs

This work adopts a simplified analytical approach to design an axi-symmetric bitter circular coil and presents a sequential-coupled simulation of electromagnetic welding for tubular jobs using finite element analysis. A three-dimensional axi-symmetric transient electromagnetic model is proposed to predict the developed magnetic field and pressure, which is sequentially coupled to the mechanical model to obtain the deformations occurring on the mating members. Results in the form of changes in impact velocity, shear stress, and effective plastic strain induced on the outer wall of the flyer tube with varying process parameters, via input voltage and initial angle of taper of inner solid plug during welding simulation are graphically shown. Based on the results of the coupled finite element simulation, a weldability window for effective welding of tubular jobs is proposed.

Explosive Welding of SS304 and Al6061 Using Copper as Interlayer – Development of Trial Methodology and its Optimisation

This paper explains the technique of explosive welding for joining SS304 and Al 6061 using Copper interlayer. The joining was done in two stages. In the first stage SS304 (thickness: 20 mm) was joined to Copper (thickness: 3mm). Second stage involved joining of SS-Cu plate to Al 6061 (thickness: 8 mm).The paper presents detailed discussion on important parameters required for explosive welded process. The most important parameter is minimum and maximum flyer plate velocity required for creating the impact. Collision angle and angle of impact are also discussed. Another important parameter is the Velocity of detonation (VOD) of explosive to be used. The explosives used have VOD of the order of 2500 m/s and 1600 m/sec. Since the explosive welding process involves formation of jet between two surface, therefore surface conditions of the base and flyer plate like its flatness, roughness and cleanliness which are very critical for proper joining have been discussed in this paper. Chisel test (which is considered to be most rugged test) was conducted on the joint. The test confirmed successful joining.The paper explains how use of trimonite expands the weldability window in comparison to NGU when used for direct SS to Al alloy welding.It also compares the results obtained by use of two different powder explosives to obtain the same tri-layered plate via two different routes. The results are particularly interesting because both the explosives have substantial difference in their properties such as Velocity of Detonation, Gurney Characteristic Velocity, density and homogeneity which can be used as advantages from different angles of views.

Arbitrary Lagrangian Eulerian FEA Method to Predict Wavy Pattern and Weldability Window During Magnetic Pulsed Welding

Finite element simulations of high strain rate forming processes have received significant attention over the last decade. For instance, in Magnetic Pulsed Welding (MPW), extremely high plastic strain regions develop. Thus, a traditional pure Lagrangian analysis is not able to accurately model the process due to excessive element distortion near the contact zone. In this study, the Arbitrary Lagrangian Eulerian (ALE) method is used to simulate a MPW process while retaining a high-quality mesh. Also the ALE method was able to numerically predict the necessary process parameters to achieve a wavy pattern region for two Al6061-T6 plates impacted during the MPW process. The captured wavy pattern region in this study can be used as a first estimation of parameters necessary to achieve a successful MPW component and thus reduce trial and error experimental investigations.