Effect of process parameters on interfacial temperature and shear strength of ultrasonic additive manufacturing of carbon steel 4130

Ultrasonic additive manufacturing (UAM) is a solid state manufacturing process capable of producing near-net-shape metal parts. Recent studies have shown the promise of UAM welding of high strength steels. However, the effect of weld parameters on the weld quality of UAM steel is unclear. A design of experiments study based on a Taguchi L16 design array was conducted to investigate the influence of parameters including baseplate temperature, amplitude, welding speed, and normal force on the interfacial temperature and shear strength of UAM welding of carbon steel 4130. Analysis of variance (ANOVA) and main effects analyses were performed to determine optimal weld parameters within the process window. A Pearson correlation test was conducted to find the relationship between interfacial temperature and shear strength. These analyses indicate that the highest shear strength of 392.8 MPa can be achieved by using a baseplate temperature of 400°F (204.4°C), amplitude of 31.5 μm, welding speed of 40 in/min (16.93 mm/s), and normal force of 6000 N. The Pearson correlation coefficient is calculated as 0.227, which indicates a weak positive correlation between interfacial temperature and shear strength over the range tested.

Mathematical modelling of fluid flow in electromagnetically stirred weld pool

In this paper, a mathematical model has been proposed to study the relationship between electromagnetic stirring (EMS) weld parameters and the mode of fluid flow on grain refinement of AA 6060 weldments. For this purpose, fluid flow modelling using Navier-Stokes equation is described first, and then, the proposed mathematical approach has been discussed in detail. For demonstration, calculations to determine the fluid velocity in the weld pool of thin plate AA6060 were performed. The application of the model on the experimental results indicates that the best grain refinement is achieved at a transition mode from laminar to turbulent fluid flow.

Study on Effect of Laser Process Parameters on Laser Transmission Weld Parameters using ANSYS

In recent years, a mode of welding that has garnered a considerable amount of interest is the laser transmission welding of thermoplastics. Laser transmission welding is now being used as an alternative to adhesives to join two thermoplastics. In this study, a finite element model has been developed to simulate the laser transmission welding of polypropylene. The movement of the laser beam was done using a Moving Heat Source in Ansys®. Process parameters namely laser power, welding speed, and the number of passes have been studied in order to investigate their effects on the temperatures and the weld widths achieved during welding. It was found that an increase in the laser power had a positive effect on the maximum temperature at the weld interface as well as the weld width. Similarly, an increase in the welding speed had a negative influence on the maximum temperature at the weld interface as well as the weld width.

Crack Repairing of Aluminum Alloy 6061 by Reinforcement of Al2O3 and B4C Particles Using Friction Stir Processing

Crack repairing of aluminum alloys is done using conventional welding techniques or mechanical methods, which results in the redundancy of mechanical properties due to defects formation. Friction Stir Welding/Processing (FSW/FSP) is a solid-state joining technique which is used to join various different similar and dissimilar metals, along with the fabrication of surface composites to cater the mentioned problem. The objective of this study is to repair the crack produced in 6061 aluminum alloy by the reinforcement of ceramic particles, Al2O3 and B4C, to further increase the efficiency of the joint along the crack line. Weld parameters, equipment used and the processing conditions are emphasized. The mechanical testing and the characterization of the weld as well as base metal was done and compared using tensile testing, micro hardness test and microstructural analysis. X-Ray Diffraction (XRD) was performed for crystallinity and intermetallic study. The dispersion of the particles was investigated using Field Emission Scanning Electron Microscope (FESEM). The crack in the Al-6061 was effectively repaired using FSP. The reinforced samples showed improved mechanical properties as compared to non-reinforced ones.

Microstructure Analysis of Hybrid Laser Powder Bed Fusion and TIG Welding of Ni-based Superalloys

The industrial use of laser powder-bed fusion (L-PBF) in turbomachinery is gaining momentum renderingthe inspection and quali?cation of certain post-processing steps necessary. This includes fusiontechniques that allow to print multiple parts separately to take advantage of e.g. various print orientationsand join them subsequently. The main motivation of this study is to validate the tungsten inertgas (TIG) welding process of L-PBF manufactured parts using industrial speci?cations relevant for gasturbines to pave the way for the industrial production of modular build setups. For this, two commonlyused nickel-based super alloys for high-temperature applications, Inconel 718 and Inconel 625 are chosen.Since their defect-free printability has been established widely, we focus on the suitability to be joined usingTIG welding. The process is evaluated performing microstructural examination and mechanical testsin as-built as well as heat-treated samples. The welds are assessed by applying a general weld quali?cationapproach used at Siemens Gas and Power. It was found that both materials can be joined via TIGwelding using standard weld parameters causing minimal defects. A solution annealing heat treatmentbefore welding is not necessary for a positive outcome, but still recommended for Inconel 718.