In this study, the microstructural features of 7A52 heat-treatable aluminum alloys welded by variable polarity plasma arc (VPPA) combined with gas metal arc welding (GMAW) (VPPA–GMAW) were investigated and compared with those of 7A52 aluminum alloys welded by GMAW The grain structures and modification of the precipitates were analyzed by optical microscopy and transmission electron microscopy Complementary to modification of the precipitates, the precipitation evolution in the heat-affected zone and magnesium loss in the fusion zone were measured by differential scanning calorimetry and inductively coupled plasma spectroscopy In VPPA–GMAW, the weld only needs one pass by depositing on one side of the 10-mm-thick aluminum alloy plates because of the large penetration capability of VPPA and good fluidity of the molten metal in the weld pool Accordingly, the effect of excessive heat input on the microstructure can be minimized The results show that the grain growth is not obvious and the magnesium loss is small in the fusion zone of VPPA–GMAW compared with that of GMAW under the condition of equal heat input to the workpiece Small precipitates inside the grains remain homogeneously distributed, and a large volume fraction of the η′ phase exists The VPPA–GMAW weld exhibits less tendency to soften; thus, VPPA–GMAW is appropriate for welding thick-plate aluminum alloys with a high production rate

Microstructural Investigation of VPPA–GMAW Welded 7A52 Aluminum Alloys

High Strength Aluminum Alloy is usually used in transmission line rush-repair tower to meet the requirements of component strength and structure weight. Aluminum Alloy has different composition and heat treatment state, and its properties vary greatly. In this paper, Al-Mg-Si Alloy 6061-T6 and Al-Zn-Mg Alloy 7003-T6 are selected to test. The test was carried out to reseach the Weldability of two kinds of Aluminum Alloy, with two Specifications and two kinds of welding wire. The purpose of this paper is to provide a reference for the selection of materials and the connection of members in the emergency repair tower of Aluminum Alloy.

https://iopscience.iop.org/article/10.1088/1755-1315/621/1/012060/pdf

Experimental study on Tig welding properties of 6061 and 7003 aluminum Alloys

Two welding tests of 1.5 mm 5A06 aluminum alloy plate welded with 1.5 mm L3 aluminum plate and 3 mm 5A06 aluminum alloy-plate with 3 mm 5A06 aluminum alloy plate were conducted by welding method of pulse changing polarity TIG.The influence rule of pulse frequency,basic value current and duty ratio on weld microstructure and mechanical property was researched when other two conditions were unchanged.The research indicates when pulse frequency is 100 Hz,basic value current is 10%～33% of peak value current and duty ratio is 50%～66%,the welded joint possesses good microstructure and mechanical property.

Ma Ji

Papers

Influence of welding parameters of pulse TIG on weld microstructure and mechanical property of aluminum alloys