Connecting parts through welding as permanent connections can play an important role in various industries. Despite the favorable load-bearing capabilities of joints resulting from welding dissimilar parts, they have some limitations that need to be identified and checked to optimize their use. One of the limitations is the behavior of parts under thermal stresses caused by the welding process. Thus, it is important to consider the welding conditions of the dissimilar parts in the contact area of the electrode and the welding seam, as this can significantly affect the mechanical performance of the welds. The research conducted in this study involved using the electric welding method with non-consumable tungsten electrodes under shielding gas (TIG) to connect aluminum and carbon steel parts. Ansys software was utilized to investigate the effect of thermal stress in the welding process for different joints. To ensure accuracy, parts were welded together practically under similar conditions, and the results obtained were compared with the results of the modeled method. First, the behavior of a steel sheet under the butt and Tee Joint and then the role of various factors on welding performance were investigated by modeling the process for a pipe in different conditions. Finally, due to the significant role of T-shaped joints in various industries, heat distribution, behavior, and stress analysis were investigated. پرونده مقاله

The correct selection of input parameters in the electric discharge machining (EDM) process leads to improvements in the material removal rate (MRR), dimensional accuracy of the parts, quality of the surface finish, and reduction of tool wear. The main goal of the research was to investigate the type and extent of the influence of input on output parameters in EDM operations. Experimental data and the contribution of parameters were obtained using the Taguchi test design with three levels. The tool used was made of copper. Samples were selected from three types of alloy steel: 4340, Ti6Al-4V, and AISI D2 steel. The test variables included maximum current (Ip), gap voltage (Vg), and duty factor (DF). In these experiments, Ip values of 5, 10, and 15 amps, Vg values of 25, 50, and 75 volts, and DF values of 0.3, 0.6, and 0.9 were selected. The number of machining operations was 81 tests, and the L9 orthogonal array related to the Taguchi approach used for Design of Experiments (DOE) reduced the number of machining operations from 81 to 27 tests. The results indicated that the current parameter of 5 amps had the highest effect on surface roughness (SR) in samples of AISI4340 steel. The current of 15 amps had the greatest impact on MRR, while the duty factor (DF) of 0.6 played the highest role in electrode wear rate (EWR). Maximum Ip contributed 36.77%, Vg contributed 31.03%, and DF contributed 32.18% to EWR. پرونده مقاله

Cryogenics is a field that involves producing, storing, transporting, and using materials at freezing temperatures. One application of this technology is in the shrinkage fitting process, where coolant materials like liquid nitrogen are used to reduce the dimensions of parts so that they can be joined together. This technique is often utilized in sub-assemblies to create a strong fit between the internal and external surfaces of components, which eliminates relative movement between parts, allowing force to be directly transferred from one part to another. In a recent study, we investigated different methods for fitting bush and axle parts with precise dimensions. Cryogenic, pressing, and thermal methods were utilized for assembly fitting. The cryogenic and thermal methods utilized contraction and expansion of parts for assembly fitting, while no dimensional changes occurred in press fitting. Results from the study showed that the cryogenic method required less force for the assembly and disassembly of parts, and the surface quality of the parts after disassembly was better compared to the other methods. Metallographic tests demonstrated that the microstructure of the parts did not change, and impact tests showed that there was no decrease in the toughness of the parts after the cryogenic operation. Based on these findings, the researchers concluded that the cryogenic method is an excellent technique for fitting SAE4140 Steel parts. پرونده مقاله