Journal of Welding Science

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.

This study presents a comparative evaluation of SMAW and GMAW welding processes for blade-to-shaft joints in St37 steel industrial mixers operating in lead-processing environments. The effects of welding process selection and joint geometry modification on the microstructural and mechanical properties of the welded joints were investigated. The results showed that the use of the GMAW process reduced the average heat-affected zone (HAZ) width from 1532 μm to 871 μm, corresponding to a 43.1% reduction compared to SMAW. In addition, the ultimate tensile strength increased from 376 MPa for SMAW joints to 400 MPa for GMAW joints, representing a 6.4% improvement. Microhardness measurements revealed an increase in the average HAZ hardness from 145 HV to 160 HV, corresponding to a 10.3% increase. Microstructural examinations also revealed noticeable differences in the characteristics of the weld metal and HAZ produced by the two welding processes. The findings indicate that the combination of GMAW and optimized joint geometry can improve the mechanical performance and reliability of blade-to-shaft joints in industrial mixers.