Showing 3 results for Design of Experiment
M. Atashparva, M. Hamedi,
Volume 3, Issue 2 (1-2018)
Abstract
Nowadays, due to the need for miniaturization, small scale resistance spot welding is of interest. The key factor that determines the nugget size is contact resistance. In this paper a new equation is provided to calculate the electrical contact resistance. The model can predict the high temperature contours and the nugget configuration efficiently. Also, a set-up was constructed to verify the model and investigate the effects of parameters on the mechanical properties of Hastelloy X welded joints. DOE analysis is done to recognize the effect of parameters on the nugget diameter, maximum load, and nugget height. It was concluded that the size of the nugget enlarges by increasing welding current and time. The nugget diameter decreases with increase of force.
M. Yousefieh, M. Tamizifar, S.m.a. Boutorabi, E. Borhani,
Volume 3, Issue 2 (1-2018)
Abstract
In the present research, the parameters of FSW process were optimized for the mechanical properties of thin aluminum- scandium alloys by a design of experiment (DOE) technique. The optimum conditions providing the highest mechanical properties were found by this method. Among the three factors and three levels tested, it was concluded that the tool rotational speed had the most significant effect on the mechanical properties and the travel speed had the next most significant effect. The effect of tool tilt angle was less important when compared to the other factors. The EBSD results demonstrated a recrystallized equi axial structure and the existence of a mixture of B and Ccomponents in the weld nugget.
Majid Aslani, Mahdi Rafiei,
Volume 7, Issue 2 (1-2022)
Abstract
In this study, in order to modify the weld structure obtained from repair welding of AZ91C magnesium alloy and improvement of tensile strength, input parameters such as current intensity and preheating temperature were optimized for this alloy. T6 heat treatment was separately done befor and after the welding to homogenize the microstructure and improvement of the mentioned properties. Using variance analysis, the accuracy of the models was checked and analyzed. Optical microscopy, scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS) and tensile tests were used to characterize the microstructure and mechanical properties of the repaired parts. The results of microstructural studies showed that the samples 2 (samples that were subjected to T6 heat treatment before and after welding) had continuous precipitates which these precipitates affected the strength due to the interruption of more slip planes and creating stronger barriers in the path of dislocations, resulting the better mechanical properties as compared with samples 1 (samples that were subjected to heat treatment only after welding). Also, by plotting response surface graphs and level diagrams, the highest tensile strength for samples 1 was observed at preheating temperatures of 493 to 513 K and current intensities of 80 to 90 A, and for samples 2 at temperatures of 513 to 553 K and current intensities of 100 to 110 A.
