Journal of Welding Science

In this study, the metallurgical and mechanical properties of the interface obtained by explosive welding of 8-92 phosphor bronze to St37 carbon steel were investigated. The effects of explosive welding parameters such as explosive charge amount and stand-off distance on the shape and microstructure of the interface, mechanical properties and corrosion behavior were investigated. The results showed that with increasing stand-off distance and explosive charge amount, the velocity and angle of impact increased, and this phenomenon led to the interface transforming from a smooth to a wavy state and resulting in melted and separated regions. The results obtained from scanning electron microscope (SEM) images showed that with increasing stand-off distance and explosive charge amount and consequently increasing impact velocity, the length and height of the waves created at the interface increased. Energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis showed that no intermetallic compounds were formed at the joint interface. The results of the microhardness test also indicated that the hardness around the joint interface increased by 25% due to plastic deformation and work hardening caused by the intense impact of the base and flying plates. By performing shear strength tests, it was found that in all samples, failure occurred in the phosohor bronze layer and no failure occurred due to separation of the samples from the interface. By performing tensile tests, it was found that the ultimate tensile strength increased from 430 to 488 MPa with increasing stand-off distance and explosive load. Polarization acquisition and impedance spectroscopy (EIS) tests showed that with increasing impact energy, the corrosion potential decreased and the corrosion current density increased significantly from 5.5 to 13.2 μA/cm².

Copper coils are essential components of induction hardening machines. The traditional manufacturing process of these coils utilizes extruded copper profiles. In this study, the production of copper profiles using metal 3D printing was experimentally investigated. Two copper samples with hollow square cross-sections, produced by extrusion and metal 3D printing, were evalated for the purpose of manufacturing induction hardening coils. Density, electrical conductivity, hardness, and surface roughness tests were performed in accordance with the relevant standards. The quantitative results for the extruded and 3D-printed samples were, respectively: density of 99% and 93% of the theoretical density of copper; electrical conductivity of 100.8% and 99.1% relative to the annealed copper standard; Brinell hardness of 50 and 59 HB; and surface roughness (Ra) of 0.324-0.533 and 11.949-13.194. The results indicated that the extruded sample possessed higher density, superior electrical conductivity, and a smoother surface, whereas the 3D-printed sample exhibited higher hardness, lower density, and greater surface roughness. These findings demonstrate that metal 3D printing can be utilized for the manufacturing of induction hardening coils.

In the present study, 316L stainless steel walls were fabricated using the WAAM process under controlled primary parameters including welding current, voltage, torch travel speed, and wire feed rate. The solidification behavior, microstructural evolution, and mechanical performance of the WAAM-produced 316L stainless steel were systematically investigated. Microstructural observations revealed that the final structure consists of a γ austenitic matrix containing approximately 8.5% δ ferrite. Tensile testing demonstrated the simultaneous achievement of high strength and ductility. Specimens extracted perpendicular to the build direction exhibited an ultimate tensile strength of about 569 MPa, a yield strength of 378 MPa, and an elongation of approximately 69%. Mechanical anisotropy was estimated to be around 7.5%, attributed to the directional growth of columnar grains. The enhanced ductility compared to conventional cast steels is associated with the fully austenitic matrix, the controlled amount of δ ferrite, the refined dendritic microstructure, and the localized annealing effect resulting from the deposition of successive layers. Microhardness measurements along the build height indicated a gradual decrease in hardness with increasing distance from the substrate, caused by grain coarsening due to heat accumulation and the lower cooling rates in the upper layers. Overall, the findings demonstrate that the WAAM process is capable of producing 316L stainless steel with a balanced combination of high strength and ductility, provided that solidification behavior and thermal history are properly controlled. These results may serve as a basis for microstructure optimization and anisotropy reduction in industrial additive manufacturing applications.

The joining of dissimilar aluminum sheets is an important issue in the optimization of industrial joints due to the differences in physical, mechanical and metallurgical properties. In this study, the mechanical behavior and microstructural changes of bimetallic joints made of AA5052 and AA3105 alloys joined by two methods of TIG welding (TIG) and friction stir welding (FSW) were investigated and compared. First, preliminary experiments were carried out to optimize the parameters of the friction stir welding and TIG welding processes and to select appropriate levels of the process parameters. The results of mechanical experiments showed that in the FSW welded samples, the failure occurred mainly in the weld zone, but in the TIG welded samples, the failure occurred in the base metal. The tensile test results showed that the AA5052 sample had the highest tensile strength (273 MPa) and the highest elongation percentage (20%), and the F 3-5 welded sample with a strength of 89 MPa and 6% elongation performed worse than the T 3-5 welded sample and fractured in the weld area. The microhardness test results showed that the TIG welded sample had a higher hardness in the weld area than the FSW method due to the use of 5356 ER filler. Finally, by analyzing and comparing the results obtained from the tests related to the mechanical properties obtained from each method, it was found that the TIG method performed better than FSW in joining some alloys.