Efficiency Of Welding Process Research Articles

Underwater wet welding of high-strength low-alloy steel using self-shielded flux-cored wire with highly exothermic Al/CuO mixture

Underwater wet welding processes with minimal energy consumption and high efficiency is the future goal for researchers in the field. Al/CuO exothermic mixtures in consumables for land welding process can improve welding process stability and decrease the electrical dependence of the welding process. To confirm the beneficial effects of Al/CuO thermite and gain a better understanding of metallurgical properties of the thermite welds in underwater environment, this study investigated underwater wet self-shielded flux-cored arc welding (FCAW-S) of high-strength low-alloy steel with highly exothermic Al/CuO mixture. The effects of Al/CuO thermite on arc stability, weld metallurgical behavior and melting characteristics of flux-cored wire were clarified. The ratio of chemical heat in the flux to the heat required to melt welding wire increased from 4.7% to 38.4% with the addition of Al/CuO, potentially accelerating the melting of flux-cored wires. The arc stability with thermite addition was superior to that without the addition of thermite. The presence of copper as a result of metallurgical reactions had a substantial impact on metallurgical behavior of underwater wet welds. The ferrite weld was a non-equilibrium Cu supersaturated solid solution, which increased the microhardness and tensile strength of wet welds. The measured cooling time proved that the incorporation of Al/CuO had the capacity to reduce cooling rate. The incorporation of 50 wt% thermite yielded a 7.8% increase in welding process efficiency compared to the base formulation. Current work provided an important direction for the development of a chemically self-heating flux-cored wire.

Identifying the influence of transient thermal tensioning treatments on minimizing distortion and improving fatigue behavior of steel welded

Due to the cost efficiency of welding repairs, the use of transient thermal tensioning (TTT) has begun to be applied to minimize distortion and residual stresses, particularly on thin plates. However, it requires a long preheating time especially on large structures, so that the efficiency of welding process cannot be maximized. Application of TTT treatment using flame heater on TTT treatment which require no preheating time so that welding efficiency can be increased. The aims of this study are to investigate the TTT treatment in reducing distortion, investigate the effect of TTT treatment on tensile strength and hardness, investigate the microstructure and its effect on tensile strength and hardness, investigated the effect of TTT treatment on fatigue crack growth rate. In this research, TTT treatment was performed by flame heating on the both side of weld line integrated in welding process. Temperature in both side plates were controlled and measured using thermocouple. The tests on the weld joints were carried out including distortion measurement, microstructure examination, hardness measurement, tensile test and fatigue test. Results showed that the TTT (60) treatment is the most effective in decreasing the longitudinal distortion which placing the flame heating a 60 mm behind welding torch. It tends to increase the tensile strength of weld metal supported by its increasing hardness. The increase in the percentage of the acicular ferrite phase is linearly related to the tensile strength and hardness of the weld joint. The fatigue behavior could be improved by TTT treatment (60) which is associated with the effect of decreasing residual stress in the weld metal region. This treatment is the best parameter in an effort to increase the welding efficiency of the TTT method

The Use of Silicon Production Waste as an Effective Additive in the Manufacture and Machining of Various Materials

The article describes the results of experiments on the use of silicon production waste as an additive that improves the structure and properties of materials and the efficiency of welding process. The flotation technology can be used to separate gas cleaning dust, which is a silicon production waste product, into commercial products. The chamber product, containing ultrafine silica, was used as a modifying additive in concrete. It improved its structure and increased its strength compared to the samples without additives. The modifier made from chamber products introduced into gray cast iron made it possible to obtain graphite of a more favorable shape as compared to the lamellar form of graphite in traditional gray cast iron. Its strength increased. The experimental results on the welding process with an activating flux, which includes ultrafine silica isolated from the metallurgical waste, are presented. The activating flux improved the penetrating ability of the welding arc by 1.5-3 times, the energy consumption decreased by 30-50%.

МАГНІТНЕ ПОЛЕ ЗВАРЮВАЛЬНОГО СТРУМУ

The use of one-sided high-speed welding is limited by a decrease in process stability, quality and welded joints toughness. The process stability determines the welds formation, the quality and welded joints toughness. Therefore, increasing process stability, quality and welded joints toughness is an important scientific and technical problem. The welding current magnetic field is created by the arc current and the current flowing through the liquid and base metal. The arc magnetic field creates a pinch-effect and compression under. the action of its own magnetic field, which concentrates energy and increases the electrode, the base metal melting and the welding process efficiency, reduces heat input and increases the welded joints toughness. The magnetic field of the current flowing through the liquid and base metal leads to magnetic blowing, which is the result of arc deflection according to the minimum energy law towards a lower magnetic field, process stability violation, lower quality and welded joints toughness. To regulate and use the welding current magnetic field, a method has been developed for measuring the magnetic field in the joint gap on the upper, lower surface and in the metal thickness middle when current flows through the plates and pipe, the adequacy of which is confirmed in the production conditions of pipe welding for gas and oil pipelines. The developed research technique provides of the welding current magnitude and magnetic field distribution the measurement in the junction gap of the plates and the pipe, which prevents the formation of undercuts and magnetic blowing during one-sided high-speed welding, increases the process stability, the quality and welded joints toughness.

Implementation of a 2-axis Additional Axes Strategy on a 6-axis Articulated Robot for Improving Welding Process Efficiency

Implementation of a 2-axis Additional Axes Strategy on a 6-axis Articulated Robot for Improving Welding Process Efficiency

Effects of shielding gas control: welded joint properties in GMAW process optimization

One function of shielding gases used in welding processes, such as hydrogen (H2), oxygen (O2), carbon dioxide (CO2), nitrogen (N2), helium (He), argon (Ar) and their mixtures, is protection of the weld pool against harmful contamination that could generate defects. In addition to this primary function, shielding gases significantly affect the shape of the weld, weld geometry, seam appearance, metallurgical and mechanical properties, welding speed, metal transfer, arc stability or beam and fume emissions. The shielding gas is thus a key factor in determining weld joint properties and welding process efficiency. As welding processes have become enhanced and welding research has advanced, different combinations of shielding gas mixtures have become available under a wide variety of trademarks, each claiming to offer the best efficiency. The shielding gas flow rate in GMAW welding is usually set according to empirical experiment. The flow generally remains unchanged throughout the entire welding process and is set at maximum values of the welding parameters so that there is sufficient gas cover. This setting means, however, that unnecessarily large quantities of shielding gas may be consumed in other phases of the welding process. In view of constantly increasing prices and shortfalls in helium supply, there is a need to optimize the use of shielding gas. Consequently, an ability to closely monitor the shielding gas blend and reduce waste can provide valuable cost savings. This paper examines the effects of shielding gas mixtures and their components, presents a cross-comparison of shielding effects in fusion welding and suggests guidelines for adaptive controllability of shielding gas in advanced adaptive fusion welding. The study reviews scientific case studies and experiments from the point of view of the effect of the shielding gas on the process efficiency and process outcome. The study considers shielding gases for welding of both ferrous metals (i.e. carbon steels, stainless steels, high-strength steels) and non-ferrous metals (i.e. aluminium and its alloys, nickel and its alloys and copper and its alloys). Appropriate choice of shielding gas and use of an optimum flow rate results in better quality in terms of increased productivity, reduced gas consumption and improved weld geometry properties, microstructure and mechanical properties. Although some blends can be used effectively in many different processes, other blends appear process-dependent; they produce far poorer results when utilized in non-appropriate processes. Particle image velocimetry (PIV) and Schlieren techniques can be used for visual sensing of gas flow during fusing welding. Moreover, an adaptive alternative gas supply can improve welding performance and weld quality and reduce harmful fume emission.

Improving Laser Beam Welding Efficiency

Laser beam welding is becoming widely used in many industrial applications. This paper reviews recent research conducted on the performance, potential and problems of thick section butt joint laser welding. Common defects that occur in laser beam welding with high power laser welding are discussed and possible solutions proposed. Methods of welding process efficiency improvement are analyzed.

Methods for Improving Laser Beam Welding Efficiency

Abstract The aim of this paper is to evaluate methods for improving laser beam welding efficiency, namely, obtaining increased penetration depth and enhanced weld quality without an increase in laser power or a decrease in welding speed. Increased efficiency can be realized with several techniques: butt joint edge surface modifications, preheating and modifications of ambient atmospheric conditions. Methods for laser beam welding process efficiency improvement are analysed and compared both separately and combined. Improvement in penetration depth or welding speed with similar penetration depth was noted for all the techniques studied.

溶接プロセスの高効率化 溶接電源・機器による高効率化

溶接プロセスの高効率化 溶接電源・機器による高効率化

The Energy Transfer Efficiency in Laser Welding Process

The process efficiency of laser beam welding was measured as a function of travel speed. Temperature measurements were carried out during the bead-on-plate laser welding of mild steel with a focused 2KW CO2 laser beam at various welding travel speeds. The laser welding process efficiency (power delivered to work/power in the beam) was calculated from the ratio of the heat content of the welded the specimen to the available laser beam energy (power × time). In the deep penetration welding region at intermediate travel speeds, the laser beam welding process efficiency (equal to the beam absorptance) was about 65%; but it was only about 28% in the shallow penetration region at high travel speeds. In deep penetration welding, multiple reflections within the penetration cavity enhance absorptance. A calculation based on four reflections within the cavity can account for the observed process efficiency.