Study on pulsed-arc welding issues at the Machines and Welding Production Automation Department, RIAE — DSTU

Abstract

Introduction. The history of solving the problem of welding structures made of stainless and heat-resistant metals and alloys goes back several decades. Researchers were particularly interested in working with deformed aluminum alloys 2–6 mm thick. As a rule, such thin-walled structures are welded in an argon shielding gas at relatively small currents; therefore, metal transfer is large-droplet (the weld is shaped in the form of separate large droplets with a narrow penetration of the welding components). At the same time, the weld is very convex, which does not meet the operational requirements of the structures. Thus, it was important to solve the following problems: to obtain a controlled fine-drop transfer of electrode metal at currents corresponding to a large-drop transfer; to determine a condition for the controlled transfer; to develop a power supply system for the welding arc.Materials and Methods. The behavior and parameters of the arc were recorded through the high-speed film and video shooting with synchronous oscillography of the electrical process parameters – current and voltage. They were recorded by light-beam oscilloscopes and two-screen oscilloscopes. The data were processed using a computer complex and Diadem 10.1 software.Results. The basic condition for the controlled metal transfer is determined through applying current pulses to the welding arc from special pulse sources with and without energy storage devices. Transients in the electrical circuits of the main welding source during the current pulse action and pause are considered. The factors providing stability of rigid and flexible pulsed-arc welding (PAW) are indicated.Discussion and Conclusions. The results of studying the possibility to control the welding arc processing behavior and the proposed methods for calculating the parameters of the PAW mode became the basis for the development of technology and equipment for the mechanized GMAWP of aluminum alloy assemblies. They are introduced at the enterprises of the aviation industry, shipbuilding. Solutions for stainless and heat-resistant steels and alloys are used at the motor industry enterprises. As a result of studies on the mechanized CO2 activated electrode wire welding, a mechanized PAW technology was developed for units of stainless steel electric furnace bodies, structures of road-building, agricultural machinery and ships.

Keywords

• welding in shielding gases
• consumable electrode
• current pulse parameters
• controlled metal transfer