Application of surfacing using consumable electrode with an additional filler wire to ensure the required operational properties of pipeline valves

A promising way to ensure the required operational properties of pipeline valves with a significant increase in productivity and quality of surfacing during its manufacture is the introduction of anti-corrosion surfacing technologies using a consumable electrode with the supply of an additional filler wire. A solution to the optimization problem of the proposed surfacing technology is complicated by a large number of its parameters, therefor the task was solved in stages. At the first stage, the parameters of the arc interaction between the electrode and filler wire was determined, and at the second - the specific features of the formation of the surfacing bath with such interaction. A virtual study of the process of surfacing with Inconel 625 wires in argon on steel 09G2S was carried out. The influence of the thermal effect of the deposition mode parameters on the main metal is determined. It has been established that, due to the fact that the heat flux in the main metal is created mainly by the droplet stream of the deposited metal from the main arc at high currents, the diameter of the electrode wire guaranteeing its burning should be larger than the filler wire. © Published under licence by IOP Publishing Ltd

The study of the influence of deviations of the arc energy parameters on the defects formation during automatic welding of pipelines

Modern quality management systems for welding products are based on procedures to minimize the likelihood of typical defects. The reasons for deviations of the energy parameters of the welding process include disturbances along the length of the arc or its breaks associated with a spasmodic change in the electrode wire feed speed, violation of the power circuit with the welded product, mains voltage, and shielding gas consumption. To establish a connection between deviations of the welding parameters with the quality indicators of the welded joints, a model for the formation of a weld seam under the conditions of technological disturbances has been developed. It is shown that the formation of the crater depends not only on the duration of the arc break, but also on the welding parameters. It has been established that in the presence of lateral oscillation of the electrode, an arc break significantly increases the undercut, the maximum depth of which movesto the center of the groove to the cutting center as the break duration increases. Whereas an increase in the amplitude of lateral oscillation of the electrode causes a significant increase in the depth of the crater. © Published under licence by IOP Publishing Ltd

Double-sided arc welding with multiple electrodes of vertical joints of steel tanks

The increase of the welding productivity is still of immediate interest, which in turn requires the development and implementation of more high-performance welding methods that ensure a consistently high quality of welded joints. One of the ways to further increase the productivity of arc welding processes in the construction of tanks is the industrial use of automatic double-sided arc welding with multiple electrodes in separate weld pools. To establish the relationship between the parameters of the welding mode, energy characteristics, as well as the distance between the torches and their angle of inclination relative to the groove, a physical and mathematical model of the production of the welding joint when four arcs participate in pairs from both sides of the joint has been developed. Thus, computer modeling showed that during weld formation with the movement of the electrode down (vertical down), the possibility of supplying each pair of arcs with pulsed current should be taken into account. During groove filling with the movement of the electrodes up (vertical up), their lateral oscillations and delays at the edges should be carried out according to an aperiodic law in order to minimize the effects of 'magnetic blow'. © Published under licence by IOP Publishing Ltd

Problems of weld overlay of seating surfaces of pipe fitting and solutions

Introduction. A problem of providing the necessary functions of pipe fitting for blockage, control, distribution of the working medium flows under the most adverse operating conditions of oil and gas pipelines associated with abrasive particles, mechanical impurities, hydrogen sulfide, carbon dioxide and organic acids with sulfate-reducing bacteria, is considered.Materials and Methods. High performance properties of seating surfaces of pipe fittings are provided through anticorrosive plating of alloyed and high-alloyed metals based on iron with the addition of chromium, nickel, cobalt and niobium. The basic weld overlay methods are analyzed: metalarc welding, nonconsumable and consumable-electrode weld facing in shielding gases, submerged arc surfacing. Advantages and disadvantages of surfacing methods implemented in recent years are noted: laser, plasma-powder and plasma-arc methods.Research Results. Taking into account the automation capabilities, a high-tech process of robotic anticorrosive surfacing using a consumable electrode with an additional filler metal feed to the front welding puddle for shielding the thermal effect of the arc, is proposed. Industrial application of the proposed technology requires a set of studies related to assessing the effect of technological parameters on the quality of the deposited layers to provide the required operational characteristics of the fitting.Discussion and Conclusion. It is proposed to carry out the above studies using physical and mathematical modeling of the anticorrosive surfacing, which reduces the time and number of experiments. Therefore, the primary task is to develop a mathematical model of the surfacing process with a consumable electrode with an additional filler wire and transverse vibrations of the welding burner. Such a model should virtually reproduce the surfacing process, as well as its thermal cycle followed by calculating the ratio of the structural components of the deposited metal and the substrate metal. The system of equations of the model should be solved by a special computer program. The algorithm presented for solving this class of problems will allow us to make a sound connection of the technological parameters of the surfacing process and the quality parameters of the formation of the deposited layers, to determine the program for their optimization to provide the required operational properties of pipeline fitting

Control of droplet transfer in consumable electrode welding with short circuiting of the arcing gap

Translated from Russian (Svar. Proizvod. 2001 (6) p. 6-9)SIGLEAvailable from British Library Document Supply Centre-DSC:9023.190(10166)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Influence of a pulsed electron beam on the sowing quality of wheat

Wheat grain has been irradiated by 200 keV and 305 keV of pulsed electron beams for changing of sowing parameters. Total microbial number, germination and germination energy were compared for both of electron kinetic energy settings for the same ranges of the energy input. The electron beam of 305 keV showed better disinfecting effect for energy input values of less than 4 J/g. That mode eliminates seed germination ability after irradiation of more than 2 J/g and can be used for grain storing. The mode of 200 keV beam keeps seed germination ability up to 5 J/g with the similar disinfecting effect after the irradiation energy input of more than 4 J/g. This mode can be used for pre-sowing seed treatment procedure

Influence of a pulsed electron beam on the sowing quality of wheat

Wheat grain has been irradiated by 200 keV and 305 keV of pulsed electron beams for changing of sowing parameters. Total microbial number, germination and germination energy were compared for both of electron kinetic energy settings for the same ranges of the energy input. The electron beam of 305 keV showed better disinfecting effect for energy input values of less than 4 J/g. That mode eliminates seed germination ability after irradiation of more than 2 J/g and can be used for grain storing. The mode of 200 keV beam keeps seed germination ability up to 5 J/g with the similar disinfecting effect after the irradiation energy input of more than 4 J/g. This mode can be used for pre-sowing seed treatment procedure

On the application of pulsed beams with a wide electron kinetic energy spectrum

The application features of pulsed electron beams with a wide electron kinetic energy spectrum for solving practical problems are considered on the example of wheat seed treatment. The influence of the dose depth distribution determined by the beam spectrum on the efficiency of its application is shown. For the ASTRA-M electron accelerator based on a pulse transformer, an operating mode has been found (accelerating voltage of 260 kV at 0.15 kGy) in which the beam energy is released mainly in the surface layer of biological materials. This leads to a sharp decrease in the degree of infection with Penicillium spp. fungi while maintaining seed germination