СONTACT BUTT WELDING OF PARTS MADE OF POWDERED ALUMINUM ALLOY AK6-PM

This article is devoted to establishing the features of the technology of butt contact welding of parts made of powder aluminum alloys. An additional task is to establish the possibility of welding rods and/or coils of wire rod with a diameter of up to 9 mm from powder aluminum alloys for subsequent drawing of rivet wire from them. For research, samples with a diameter of 8 mm were used, made of pressed rods from powder alloy AK6-PM, manufactured according to the following regime: pressing the powder in a mold with a pressure of 200 MPa, pressing the porous work piece to a density that is 95% of the theoretical, hardening and aging according to standard regimes for alloy AK6. Butt welding by fusion was carried out on “Strekker” welding machines using the following mode: welding current – ​​12000 A (current density 15000 A/cm2), fusion size – up to 8 mm, deposition size – up to 5 mm, fusion duration – up to 70 alternating current periods, deposition duration – up to 5 alternating current periods. To study the microstructure of the welded joint zone, a micrograph was made. The microstructure of the welded joint zone was studied using a scanning electron microscope MREM-100 in secondary electrons at small magnifications from 30 to 89 times. During the study, no increase in porosity in the welded joint zone was detected. To establish the physical and mechanical characteristics of the butt welded joints, samples with a length of 120 mm and 70 mm and a diameter of 8±0.1 mm were made. The magnitude of the fracture stress of the samples was investigated using a FPZ100/1 tensile testing machine. The fracture stress was from 129 MPa to 139 MPa, the relative elongation from 9.6% to 14%. For further research, samples of butt welded joints were manufactured, which after turning the grid were subjected to quenching from a temperature of 330C and artificial aging at a temperature of 170C. The magnitude of the fracture stress of the samples was investigated using a FPZ100/1 tensile testing machine. The fracture stress of the samples did not exceed 146 MPa, the relative elongation was 10%. As a result of the research, the value of the ultimate strength of butt welded joints of samples made of powder alloy AK6-PM, obtained from powders made by dispersing a jet of melt with high-pressure water jets, was established, which is up to 146 MPa. It was established that the porosity of samples from powder aluminum alloy AK6-PM in the zone of butt welding by fusion does not increase. Thus, the possibility of connecting parts from powder aluminum alloy AK6-PM using butt contact welding is proven. Butt welding of wire and rod from aluminum alloy AK6-PM is also possible during the rivet wire drawing process. The physical and mechanical characteristics of the butt joints of samples from powder aluminum alloy AK-6PM are not inferior to similar characteristics of welded joints of samples from alloy AK6 obtained by fusion welding in accordance with GOST 23697-79.