Fatigue of Friction Stir and GTAW Welded AZ31B Magnesium Alloy

Author(s):  
J. A. Ávila ◽  
H. E. Jaramillo ◽  
F. Franco

The mechanical behavior of butt welds made on AZ31B magnesium alloy plates by solid-state friction stir welding (FSW) and gas tungsten arc welding (GTAW) is presented. Fatigue, tensile strength, and hardness tests were performed. Also, fractographic analyses of the weld microstructures were conducted. Tests results show that the fatigue performance of FSW joints was superior to that of conventional welding (GTAW).

2014 ◽  
Vol 909 ◽  
pp. 77-82
Author(s):  
Hari Krishna Kallipudi ◽  
Rama Koteswara Rao Sajja ◽  
Venkata Subba Rao Veera

Magnesium alloy ZM21 plates were welded using friction stir welding, a solid state process and gas tungsten arc welding which is a fusion welding process. Defect free, full penetration welds were obtained after several trials using different process parameters. The effect of welding processes on mechanical properties of Mg-Zn-Mn joints were evaluated using tensile tests, bend test, vickers micro hardness measurements and optical microscopy. Welds produced by Friction stir welding process exhibited superior tensile properties compared to Gas Tungsten Arc Welding process. Hardness reduction in the weld metals were observed for both the welding techniques. Friction stir welds showed finer grains in the weld nugget and in the heat affected zone. Both types of welds exhibited good bend ductility comparable to that of the base material. It has been concluded that both the processes are well suited to obtain sound welds of the magnesium alloy ZM21 and Friction stir welding process offers stronger welds.


Author(s):  
V.A. Berezina ◽  
V.V. Ovchinnikov ◽  
E.V. Luk'yanenko

The results of technological features for friction stir welding of butt joints of sheet blanks with thickness of 3 mm made of casting aluminum V AL8 alloy with wrought magnalium group 1565chN2 and AMg6M alloys are presented. It is established that the time resistance of the joints depends on the location of the welded alloys relative to the direction of tool rotation during friction stir welding. The ultimate strength of welded joints of VAL8 alloy with 1565chN2 and AMg6 alloys in automatic argon-arc welding is 0.82...0.84 of the ultimate tensile strength of VAL8 alloy. The grain size in the stir zone practically does not depend on the initial grain size in the alloys to be joined. The destruction of the joints made of VAL8 + 1565chH2 alloys under cyclic loading has multi-focal character and is initiated from irregularities on the surface of the weld. The discrete nature of the change in the chemical composition of the weld metal along the axis of the weld is revealed. The weld is formed by alternating strips of connected alloys with width of 30...90 microns.


2020 ◽  
Vol 866 ◽  
pp. 54-62
Author(s):  
Hong Feng Wang ◽  
Sheng Rong Liu ◽  
Xiao Le Ge ◽  
Jia Fei Pu ◽  
Lei Bao ◽  
...  

10mm thickness AZ31B magnesium alloy was used as the friction stir welding object in this study. Different welding joints were obtained by setting different friction stir welding parameters. Metallographic analysis and impact loading test were carried out on the joint area. The experiment results show that (i) when the rotational speed of the stirring head is 600rpm and the welding speed is 120mm/min, the microstructure of the joint has the characteristics of compactness, thinning, and large-area twinning, which is beneficial to improve the plasticity of the joint area; (ii) the impact load of the joint is the highest, but lower than that of the base material, which is 95.5% of the base material; (iii) the fracture of impact specimen presents ductile fracture.


2011 ◽  
Vol 704-705 ◽  
pp. 786-789
Author(s):  
Guang Tao Zhou ◽  
Zi Yu Zhao ◽  
Guo Li Liang ◽  
Wei Hua Chen

Based on the gas tungsten arc welding process this paper investigated the welding temperature field measurement and simulation of 945 steel plate and AZ31B magnesium alloy, using a non-contact and fast response measured temperature method-Infrared Radiation (IR)-which utilized the baffle to remove the arc and hot tungsten electrode interference, the top-face temperature of AZ31B magnesium alloy plate and 945 steel plate. The results indicated that the lengthwise isothermal map of 945 steel plate is much longer than that of AZ31B magnesium alloy plate, which leads to the most temperature field information loss, this is because the thermal conductivity of steel is small and decreases with temperature increase, the thermal conductivity of AZ31B magnesium alloy is much bigger that that of the 945 steel, about 1.5 times of 945 steel, and increased with temperature increase. The results also showed using IR to measure the welding temperature of magnesium alloy is more difficult than 945 steel. Keywords: magnesium alloy, high strength steel, welding temperature field, IR


2003 ◽  
Vol 125 (03) ◽  
pp. D10-D16 ◽  
Author(s):  
Matt Hansen

This article provides details of a low-temperature joining technology called friction stir welding. Friction stir welding (FSW) uses a cylindrical, shouldered tool with a profiled pin that is rotated and slowly plunged into the joint line between two pieces of sheet or plate material. According to an engineer, stir welding eliminated 60 percent of the rivets that the plane would have otherwise required. Eclipse Aviation Corp., Albuquerque, NM, is building a separate plant to house its stir welding operations for commercial production, once its plane receives certification by the US Federal Aviation Administration. FSW is a solid-state process, more like forging and extruding than to fusion welding. Since the process is solid state, the joint is not subject to any shrinkage because of phase changes. The process also introduces minimal heat into the weld, so the heat-affected zone is relatively small in comparison to arc welding.


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