Showing papers on "Submerged arc welding published in 2007"

Occurrence of arc interaction in tandem pulsed gas metal arc welding

Abstract: In the tandem pulsed gas metal arc welding, the occurrence of arc interruption by the electromagnetic interaction between the two adjacent arcs becomes a problem. In order to clarify this problem, effects of interwire distance and Ar–CO2 gas mixture ratio on an abnormal arc voltage and arc interruption are investigated. The abnormal arc voltage and the arc interruption frequently occur with pulse peak currents which are supplied alternately to two wires. In addition, both phenomena occur in trailing arc which is located on molten pool at base current duration remarkably. There is most number of abnormal arc voltage and arc interruption times in trailing when the interwire distance is 10 mm, because a deflected length of trailing arc by the electromagnetic interaction becomes the longest. Moreover, the CO2 mixture ratio in shielded gas affects the occurrence of abnormal arc voltage and arc interruption. The abnormal arc voltage and arc interruption do not occur when CO2 gas mixture ratio is equal t...

Mechanism and Microstructure of Oxide Fluxes for Gas Tungsten Arc Welding of Magnesium Alloy

Abstract: Five single oxide fluxes—MgO, CaO, TiO2, MnO2, and Cr2O3—were used to investigate the effect of active flux on the depth/width ratio in AZ31B magnesium alloy. The microstructure and mechanical property of the tungsten inert gas (TIG) welding seam were studied. The oxygen content in the weld seam and the arc images during the TIG welding process were analyzed. A series of emission spectroscopy of weld arc for TIG welding for magnesium with and without flux were developed. The results showed that for the five single oxide fluxes, all can increase the weld penetration effectively and grain size in the weld seam of alternating current tungsten inert gas (ACTIG) welding of the Mg alloy. The oxygen content of the welds made without flux is not very different from those produced with oxide fluxes not considering trapped oxide. However, welds that have the best penetration have a relatively higher oxygen content among those produced with flux. It was found that the arc images with the oxide fluxes were only the enlarged form of the arc images without flux; the arc constriction was not observed. The detection of arc spectroscopy showed that the metal elements in the oxides exist as the neutral atom or the first cation in the weld arc. This finding would influence the arc properties. When TIG simulation was carried out on a plate with flux applied only on one side, the arc image video showed an asymmetric arc, which deviated toward the flux free side. The thermal stability, the dissociation energy, and the electrical conductivity of oxide should be considered when studying the mechanism for increased TIG flux weld penetration.

An evolutionary approach to parameter optimisation of submerged arc welding in the hardfacing process

Abstract: The Submerged Arc Welding (SAW) process finds wide industrial application due to its easy applicability, high current density and ability to deposit a large amount of weld metal using more than one wire at the same time. It is highly emphasised in manufacturing especially because of its ability to restore worn parts. SAW is characterised by a large number of process parameters influencing the performance outputs such as deposition rate, dilution and hardness, which subsequently affect weld quality. An exhaustive literature survey indicates that five control factors, viz., arc current, arc voltage, welding speed, electrode stick-out and preheat temperature, predominantly influence weld quality. In relation to this, an attempt has been made in this study to analyse the effect of process parameters on outputs of welding using the Taguchi method. The relationship between control factors and performance outputs is established by means of nonlinear regression analysis, resulting in a valid mathematical model. Finally, Genetic Algorithm (GA), a popular evolutionary approach, is employed to optimise the welding process with multiple objectives.

Determination of submerged arc welding process parameters using Taguchi method and regression analysis

Abstract: This paper details the application of Taguchi technique and regression analysis to determine the optimal process parameters for submerged arc welding (SAW). The planned experiments are conducted in the semiautomatic submerged arc welding machine and the signal-to-noise ratios are computed to determine the optimum parameters. The percentage contribution of each factor is validated by analysis of variance (ANOVA) technique. Multiple regression analysis (MRA) is conducted using statistical package for social science (SPSS) software and the mathematical model is build to predict the bead geometry for any given welding conditions.

Plasma properties of helium gas tungsten arc with metal vapour

Abstract: The energy source characteristics of gas tungsten arc (GTA) strongly depend on the physical property of arc plasma. In welding processes, it has been experimentally confirmed that metal vapour evaporated from a high temperature weld pool drastically changes the property of arc plasma and decreases its temperature. However, the effect of metal vapour on the characteristics of heat flux into a base metal is still not clear owing to the difficulty in experimental studies of arc plasma. In the present paper, the energy source property of helium GTA mixed with metal vapour was numerically analysed. It was found that the intense radiation generated from dense metal vapour decreases heat flux into a base metal and contracts the current density distribution especially near the arc axis.

ANFIS for prediction of weld bead width in a submerged arc welding process

Abstract: This paper proposes an intelligent technique, Adaptive Neuro-Fuzzy Inference System (ANFIS), to predict the weld bead width in the submerged arc welding (SAW) process for a given set of welding parameters. Experiments are designed according to Taguchi’s principles and its results are used to develop a multiple regression model . Multiple sets of data from multiple regression analysis are utilized to train the intelligent network. The trained network is used to predict the quality of weld. The proposed ANFIS, developed using MATLAB functions, is flexible, accurate than existing models and it scopes for a better online monitoring system.

Prediction of element transfer in submerged arc welding

Abstract: The transfer of elements across the molten weld pool has been predicted by developing quadratic models in terms of flux ingredients with the application of statistical experiments for mixture design. Bead-on-plate weld deposits were made at fixed welding parameters using submerged are welding fluxes prepared as per extreme vertices algorithm of mixture experiments in a CaO-MgO-Caf 2 -Al 2 O; flux system. The results show that some of the individual flux ingredients and their binary mixtures have a predominant effect on weld metal transfer of oxygen, manganese, silicon, and carbon contents. The analysis of experimental data also indicates that transfer of oxygen is affected by several properties of flux ingredients such as oxygen potential, thermodynamic stahility, and viscosity. In the element transfer of silicon, both thermochemical and electrochemical reaction mechanisms operate simultaneously. Transfer of manganese is principally related to the weld metal oxygen contents as well as electrochemical reaction in the molten weld pool. The transfer of carbon was generally governed by the oxidation reaction. Iso-response contour plots were also developed to quantify the transfer of elements against different flux compositions.

Submerged arc welding flux material used for high grade pipe line steel

Abstract: The present invention provides a welding flux material for submerged arc welding for welding high-grade line pipe steel and other structure steel. Its chemical composition includes (by wt%) 15%-25% of CaF2, 15%-25% of MgO, 15%-20% of Al2O3, 5%-10% of MnO, 5%-10% of TiO2, 10%-15% of SiO2, 5%-10% of CaO, 1.0%-2.5% of Na2O, 1.5%-3.0% of B2O3, 0.2%-0.4% of Re(Mg) and 3%-5% of ZrO2. Said welding flux material can be prepared by adopting sintering process. Besides, said invention also provides its application method.

Obtaining a submerged arc welding flux of the MnO–SiO2–CaO–Al2O3 – CaF2 system by fusion

Abstract: (2007). Obtaining a submerged arc welding flux of the MnO–SiO2–CaO–Al2O3 – CaF2 system by fusion. Welding International: Vol. 21, No. 7, pp. 502-511.

Effect of activating flux on arc shape and arc voltage in tungsten inert gas welding

Abstract: 在焊接弧上激活流动的效果被调查。water-cooling 系统和不锈钢的一个特殊集合被用作父母材料。在焊接过程期间，高速度的照相机系统和示波器被用于分别地捕获即时弧形状和弧电压。试验性的结果显示 SiO2 流动能增加弧电压。当 TiO2 没在弧电压上有这效果时。与常规钨相比焊接的惰性的气体(C-TIG ) ，焊接的 A-TIG 的弧形状与 SiO2 流动使用了，这被发现显然变化了。

Predictions of weld formation using gas tungsten arcs for various arc lengths from unified arc-electrode model

Abstract: Predictions have been made of weld formation for stationary gas tungsten arc welding by making two-dimensional (2D) calculations of temperature and fluid flow velocity of the arc and the electrodes The whole region of the arc system is modelled, including the tungsten cathode, the arc plasma and the workpiece anode, and convection within the weld pool Predicted properties of the weld shape for 150 A arcs in argon and helium, for various arc lengths, are compared with experimental results of cross-sectional area of weld Although total power to the anode increases with increasing arc length, for argon arcs the heat flux density at the axis of the anode becomes lower, with the result that the cross-sectional area of the weld becomes smaller with increasing arc length For helium arcs total power to the anode also increases with increasing arc length, but the distribution of heat flux density to the anode is approximately constant, with the result that the cross-sectional area of the weld increases

Study of mechanism of activating flux increasing weld penetration of AC A-TIG welding for aluminum alloy

Abstract: When multi-component flux AF305 is used as surface activating flux for an aluminum alloy, the weld penetration of activating flux-tungsten inert-gas (A-TIG) welding is over two times more than that of conventional TIG welding. Using A-TIG welding with the modes of alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), respectively, the flux differently affects weld penetration when the polarity is different. After studied the effect of compelled arc constriction on weld penetration of AC welding, it is believed that the constriction of the whole arc root is not the main mechanism that flux AF305 dramatically improves weld penetration. The penetration has a relationship with the separate distribution of slag on the weld surface. Then, an observation of scanning electron microscopy (SEM) and an electronic data systems (EDS) analysis of slag were performed respectively. The separate distribution of slag on the weld pool during welding and the great constriction of arc spots were confirmed by TIG welding with helium shielding gas. The relationship between slag distribution and weld penetration was studied by adding aluminum powder into flux AF305 to change the distribution of slag. During welding, the separate distribution of slag on the weld pool results in the great constriction of arc spots, an increase in arc spot force, and an increase in Lorentz force within the arc and weld pool. Finally, the weld penetration is increased.

Prediction of Mechanical Properties in Submerged Arc Weld Metal of C–Mn Steel

Abstract: The prediction model has been developed for steel weld metal mechanical properties as a function of flux ingredients such as CaO, MgO, CaF2 and Al2O3 in submerged arc welding carried out at fixed w...

Equipment and method for combined welding of laser and arc

Abstract: PROBLEM TO BE SOLVED: To provide equipment and a method for combined welding using jointly a laser and an arc by which high-quality weld zone where is free from the generation of weld defects such as porosity is obtained and also stable weld bead is formed. SOLUTION: By forming a fine and deep groove-like keyhole on the surface of a material to be welded by irradiation of a laser beam and generating the arc between the electrode for the heat source of the arc and the material to be welded, a molten pool is formed on the surface of the material to be welded. The keyhole and the molten pool are connected. The keyhole is shielded by laser shielding gas and the molten pool is shielded by are shielding gas. The laser shielding gas and the arc shielding gas are different gas. COPYRIGHT: (C)2009,JPO&INPIT

Mechanical properties and corrosion resistance of dissimilar stainless steel welds

Abstract: Purpose: The purpose of this paper is to determine the influence of welding on microstructure, mechanical properties, and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints. Design/methodology/approach: Duplex 2205 and austenitic 316L steels were used. Butt joints of plates 15 mm in thickness were performed with the use of submerged arc welding (SAW) method. The heat input was in the range of 1.15 – 3.2 kJ/mm. Various plates’ edge preparations were applied. Microstructure examinations were carried out. Mechanical properties were evaluated in tensile tests, bending tests and Charpy-V toughness tests. Susceptibility to stress corrosion cracking was determined with the use of slow strain rate tests (SSRT) performed in inert (glycerin) and aggressive (boiling 35% MgCl2 solution) environments. Findings: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ) of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate mechanical properties as well as stress corrosion cracking resistance of welds. Practical implications: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ) of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate mechanical properties as well as stress corrosion cracking resistance of welds. Originality/value: Mechanical properties and stress corrosion cracking resistance of dissimilar stainless steel welded joints was determined. The zone of the weaker resistance to stress corrosion cracking was pointed out.

Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints

Abstract: Purpose: The aim of the current study is to reveal the influence of welding conditions on structure and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints Design/methodology/approach: Butt joints between duplex 2205 and austenitic 316L steels were performed with the use of submerged arc welding (SAW) method The plates 15 mm in thickness were welded with heat input in the range of 115 – 32 kJ/mm using duplex steel filler metal Microstructure examinations and corrosion tests were carried out Slow strain rate tests (SSRT) were performed in inert (glycerin) and aggressive (boiling 35% MgCl2 solution) environments Findings: It was shown that place of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins That phenomenon was connected with undesirable structure of that zone consisted of great amount of coarse ferrite grains and acicular austenite precipitates High welding inputs do not deteriorate stress corrosion cracking resistance of welds Research limitations/implications: High welding heat inputs should enhance the precipitation process of intermetallic phases in the HAZ It is necessary to continue the research to determine the relationship between welding parameters, obtained structures, and corrosion resistance of dissimilar stainless steels welded joints Practical implications: Application of more productive joining process for dissimilar welds like submerged arc welding instead of currently employed gas metal arc welding (GMAW) method will be profitable in terms of reduction the welding costs Originality/value: The stress corrosion cracking resistance of dissimilar stainless steel welded joints was determined The zone of the weaker resistance to stress corrosion cracking was pointed out

Flux-cored wire for submerged arc welding of low-temperature steel, and welding method using the same

Abstract: PROBLEM TO BE SOLVED: To provide a flux-cored wire for submerged arc welding of low-temperature steel, and a welding method using the same in which the welding workability is excellent even under a high-speed welding condition, and a weld metal of excellent mechanical performance can be obtained. SOLUTION: The flux-cored wire for submerged arc welding of low-temperature steel contains, by the wire total mass% of the flux-cored wire, 0.02-0.30% C, 0.08-0.6% Si, 1.2-3.4% Mn, 0.5-3.5% Ni, and 0.03-0.8% Mo in the total of one or both of a steel shell and filling flux; 0.01-0.27% C, 2-15% CaF 2 , and 0.05-0.7% CO 2 part of metal carbonate and the balance Fe in the steel shell, Fe in alloy powder, iron powder and inevitable impurities in the filled flux; the total hydrogen amount of the wire is ≤50 ppm, the flux filling ratio of the filled flux in the components is 10-30%, and any joint is not formed in the steel shell. COPYRIGHT: (C)2010,JPO&INPIT

Three-wire submerged-arc welding method for thick plate, low alloy, high strength steel

Abstract: A three-wire hidden arc welding method for the thick plate of low-alloy high-strength steel features that three welding wires are longitudinally arranged in such manner that one is connected to positive electrode of DC power supply and another two to AC power supply to form a fusion pool, the gap between adjacent two welding wires is 10-15 mm and the included angle between welding wire and workpiece is respectively 90-105 deg, 90-105 deg, and 60-80 deg.

Sintered flux for submerged arc welding

Abstract: Provided is a sintered flux for submerged arc welding which is applied to austenite stainless steel welding. The flux includes 12.0-20.0wt% SiO2, 18.0-27.0wt% Al2O3, 6.0-12.0wt% ZrO2 6.0-12.0wt% CaO, 7.0-16.0wt% CaF 2, 2.0-5.0wt% MnO, 20.0-29.0wt% MgO, 1.5-4.5wt% Na 203, K 20, Li 20, or a combination thereof, and a remainder including Fe and inevitable impurities, on the basis of the entire weight of the flux. Therefore, it is possible to provide a sintered flux for submerged arc welding which has excellent arc stability and slag detachability during welding, prevents welding defects such as poke marks and pits, and has excellent bead shape.

Ending control method of two-wire welding

Abstract: PROBLEM TO BE SOLVED: To prevent sticking of a filler wire 6 to a molten bath 2 at the time of the end of welding of a two-wire welding that uses a welding wire 1 and the filler wire 6. SOLUTION: In the ending control method of two-wire welding, the filer wire 6 is fed, while contacting to a molten bath of a consumable electrode arc 3. When a crater process is started by the consumable electrode arc 3 at the end of welding, the reverse feeding of the filler wire 6 is started in synchronous with that. At the same time, the contacting state between the filler wire 6 and the molten bath 2 is detected, and until non-contact state is detected by the contact detection, the reverse feeding of the filler wire 6 is continued. In this way, the tip of filler wire after welding is stopped under such a state that it is away from the molten bath 2 by some distance. As a result, adhesion is prevented and next welding is started earlier to improve production efficiency. COPYRIGHT: (C)2009,JPO&INPIT

Steel sheet for submerged arc welding

Abstract: A steel plate for submerged arc welding having good low temperature toughness at a fusion line vicinity part and a boundary with the base material in HAZ as well as at the base material and the weld metal is provided. The steel plate for submerged arc welding according to the invention contains, by mass, 0.03% to 0.09% C, 1.5% to 2.5% Mn, 0.005% to 0.025% Nb, 0.005% to 0.02% Ti, 0.01% to 0.06% Al, at most 0.0005% B, 0.001% to 0.008% N, at most 0.015% P, at most 0.015% S, and at most 0.006% O, and the balance consists of Fe and impurities. Therefore, the steel plate according to the present invention has good low temperature toughness not only at the fusion line vicinity part and the boundary with a base material in the HAZ but also in the base material and weld metal.

Method of welding the plug in type connection nozzle and the un-orthogonal crossed connection nozzle of the cylinder

Abstract: The invention relates to a welding method for insertion nozzle and cylinder non-rectangular intersection connector, characterized in that saddle automatic submerged arc welding machine or deep and narrow groove welding torch is used; the groove shape is I-type, namely the angle of groove at two sides is O; the nozzle is set vertically and the cylinder is oblique; auxiliary tooling is used; the welding method from the lower part to middle part to upper part is adopted to achieve purposes of automatic submerged arc welding and control deformation. The merit of invention is that the influence of human factor to welding quality is decreased; the welding efficiency is improved greatly and the machining period is shortened; welding material can be saved notably; welding quality can be guaranteed in effect; and the machining cost is decreased greatly.

Arc start control method in consumable electrode arc welding

Abstract: An arc start control method is provided for consumable electrode arc welding. According to this method, a welding wire, supplied through a welding torch, is brought into contact with a work. Then, an initial current is applied to the welding wire and the work that are held in contact with each other. Then, an initial arc is generated by moving the welding wire away from the work with the application of the initial current maintained, and thereafter the initial arc is changed to a steady arc. The initial current is increased gradually with a predetermined increase rate for a predetermined period of time starting at beginning of the application of the initial current.

Saddle type union melt welding with plug in type little connection nozzle

Abstract: The invention relates to a saddle automatic submerged arc welding for insertion small nozzle. The method is that a ring of oblique groove is machined on the welding pore of shell; nozzles are inserted into oblique grooves of shell and are welded on inner wall of shell by gasket; electrical infrared flame is used to preheat; the submerged arc welding machine is used to weld out from the inner wall one ring by one ring. The submerged arc welding machine adopted in invention is MZMA300 submerged arc welding machine produced in Beijing. Through practical test the qualified rate of welded connector quality is more than 95% stably after tests of 100% MT and UT. The welding productivity can be improved by more than 100%. The merit of invention is stable product quality and high welding productivity.