Study On Drawing Technology And Equitment Of Magnesium Alloy Wire

Magnesium alloy is the lightest structural materials in industrial application, which own high stiffness, strength and very good processing properties. Magnesium alloys have broad application prospects in the automotive, aerospace and electronics industries, annual using is growing. However, and compared to the aluminum alloy especially steel, the current application status still not optimistic. With the development of production and technological progressing, magnesium alloy application in life and the production is gradually increasing, so it would use welding processing. Arc welding and especially fusion welding, which own advantages of high efficiency, low production cost and easy to implement automation, its superiority shows in plate welding especially. Therefore, the fusion welding may become the main welding method of magnesium alloy. The fusion welding need wires as filling materials that hold welding continuous, then the production of magnesium alloy wire is pressing demanded.The ductility of magnesium alloy is poor at room temperature, so it difficult to put out drawing processing in this condition. There are some extrusion magnesium alloy wire products in market, because of the nature with the magnesium alloy and the characteristics of extrusion process, extruded magnesium alloy wire own some shortcomings, such as wire surface is not smooth and wire diameter is uniform etc. When it is used to arc welding, such as MIG arc melting welding, the welding gun contact tip are mostly fixed diameter tubular structures which have very strict requirements for the wire diameter: if the wire diameter slightly smaller, wire will be very prone to arcing and welding together with contact tip during the welding process, which requires frequent removal or replacement of torch contact tip, and serious impact on the continuity of the welding process. When wire diameter is thicker, wire can not pass contact tip, there would be block wire. As the magnesium alloy material is brittle at room temperature, wire will be broken under the thrust in wire wheel, which also affect the continuity of the welding process. Discontinuous welding process is a serious waste of the welding materials and affects productivity also, which requires drawing magnesium alloy wire. The surface of drawing wire products is smooth and tidy, the wire diameter is uniform and size is high precision, so study on magnesium alloy wire drawing technology has further practical significance.In this paper, Magnesium alloy welding wire drawing process performance was studied through the AZ31 magnesium alloy wire drawing experiments with electric heating. The influence of various process parameters on the wire drawing plastic forming process was analyzed. Effect of the drawing process on the wire microstructure and mechanical properties was studied. A magnesium alloy wire drawing equipment was designed, and the device performance was analyzed. The main conclusions are given as follows:(1) Wire drawing deformation temperature was increased by electric heating, which sharply enhanced the plastic deformation of wire and avoided the annealing process work of softening caused by hardening.(2) Heating current and the drawing speed were important process parameters of the drawing and they were interrelated. With a certain current, heating temperature of wire was lower as drawing speed was higher.(3) After the drawing process, magnesium alloy wire organization grain is refined , from the original 50μm into 10μm after the last drawing. The mechanical property of the wire was enhanced, strength of wire was increased, microhardness was improved.(4) With heating temperature of 260℃, drawing speed of 14.5m/min, reasonable graphite lubrication and effective cooling, the drawing of the magnesium alloy welding wire was great. Surface of drawing magnesium alloy wire was clean and tidy, wire diameter was uniform, stiffness of wire was match with the warp, the microstructure of the wire was uniform and with a few broken wires.(5)A magnesium alloy wire drawing equipment was developed. The device operated easily and convenient, heating power was good, the feedback signal of sensor was used in pulse trigger circuit and the automatic adjustment of the heating current was achieved. The rate of broken wire was minimized, which ensured wire drawing process continuous.