Effect of Mg and Cu on Mechanical Properties of High-Strength Welded Joints of Aluminum Alloys Obtained by Laser Welding

2015 ◽  
Vol 220-221 ◽  
pp. 583-588 ◽  
Author(s):  
Krzysztof Dudzik ◽  
Mirosław Czechowski

The paper presents the research results on the mechanical properties of aluminum alloy 7020 and its FSW and MIG welded joints. For comparison, alloy 5083 – the most currently used in shipbuilding alloy was chosen as well as 5059 – the new high-strength alloy. Besides, the native material alloys there were investigated their joints welded by FSW and MIG – the same methods as alloy 7020. Welding parameters used for the connection of the sheets made of 7020, 5083 and 5059 alloys were presented. Metallographic analysis showed the correct construction of structural bonded joints.Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods, especially MIG, which is the most common method of joining aluminum alloys used in shipbuilding. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standards PN-EN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of +20 oC.Friction stir welded joints of tested alloys have higher strength properties as compared to MIG welded joints. The 7020 alloy has higher strength properties then alloys 5083 and 5059. The yield stress is higher by 14.8% as compared to alloy 5083, and by 11.7% as compared to the alloy 5059. Plastic properties of alloy 7020 are the lowest, but with reserves meet the requirements of classification societies. The joints welded by FSW of alloy 7020 have the highest strength properties of all researched joints – higher then alloys 5083 and 5059 joints welded by FSW and joints of all alloys welded by MIG.


Author(s):  
V.V. Ovchinnikov ◽  
R.N. Rastopchin ◽  
L.P. Andreeva

The results of the effect of scandium alloying of additive wires such as SvАМg4 and SvАМg63 on the structure and mechanical properties of welded joints of sheets and plates of 1420 alloy in mechanized single-passing and manual multi-pass welding are presented. It is shown that the introduction of 0.17...0.25 % scandium in the SvАМg4 and SvАМg63 filling wires contributes to decrease in the cracking rate and significant increase in the critical rate of deformation of the sample during welding on the МVТU sample. The level of microporosities and their location in multi-pass welding of plates of 1420 alloy depend on the magnesium content in the filling wire. The alloying of the SvАМg4 and SvАМg63 filling wires by scandium increases the ultimate strength of both the welding joint as whole and the weld metal.


2021 ◽  
Vol 2079 (1) ◽  
pp. 012022
Author(s):  
Yongchao Jian ◽  
Yan Shi

Abstract Because of the uneven distribution of reinforcement particles in the molten pool during laser welding of SiCp/6061Al composites with powder, the effect of pulse frequency on the homogenization was studied in this paper. The pulse frequency of welding is changed and the macro morphology of the weld is studied by metallographic microscope. The particle uniformity of reinforcing phase and the porosity of molten pool at different frequencies were compared. The tensile strength of welded joints at different frequencies was tested by universal tensile machine. Finally, when the pulse frequency is 160Hz, the particle distribution of reinforcing phase is the most uniform and the tensile strength is the largest. The tensile strength reaches 267.06MPa, reaching 69.1% of the base metal. When the pulse frequency is 320Hz, the porosity of the weld is the lowest, reaching 1.75%.


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