Argon-arc Welding Research Articles

ИССЛЕДОВАНИЕ ВЛИЯНИЯ АРГОНОДУГОВОЙ СВАРКИ НА СТРУКТУРУ И МЕХАНИЧЕСКИЕ СВОЙСТВА КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ АМг2-10%TiC, АМг6-10%TiC, ПОЛУЧЕННЫХ МЕТОДОМ СВС В РАСПЛАВЕ

The paper gives the results of evaluating the effect of argon arc welding on the structure and properties of AMg2-10%TiC and AMg6-10%TiC composite materials produced by SHS method in a melt. During the research, permanent welded joints are obtained, characterized by single defects such as pores and lack of fusion. Metallographic analysis shows that, unlike matrix alloys, there is no grain heterogeneity on welded samples of composite materials after crystallization of the welding bath and an equiaxed cellular structure is formed. It is found out that the welding operation leads to grain growth on all samples, but dispersed reinforcing phase slows down this process, and the smallest size of the dendritic cell, regardless of the welding zone, is observed in AMg2-10%TiC sample. At the same time, the content of titanium carbide particles in welded samples of composite materials is noted in all three zones of the weld joint, although its amount decreases as it approaches the weld. It is also found out that additional beta-phase release of Al3Mg2 composition may occur in the welding zone, but there is no Al4C3 compound, which indicates the thermodynamic stability of the titanium carbide phase. The evaluation of mechanical properties shows more satisfactory characteristics for AMg2-10%TiC composite material, which makes it possible to recommend it for the manufacture of structures with welded joints operating under static compressive loads.

A Novel Simulation Model of Shielding Performance Based on the Anisotropic Magnetic Property of Magnetic Shields.

To achieve a near-zero magnetic field environment, the use of permalloy sheets with high-performance magnetic properties is essential. However, mainstream welding processes for magnetically shielded rooms (MSRs), such as argon arc welding and laser welding, can degrade the magnetic properties of the material. Additionally, neglecting the anisotropy of permalloy sheets can introduce unpredictable errors in the evaluation of MSR performance. To address this issue, this paper proposes a modified model for calculating the shielding factor (SF) of MSRs that incorporates the anisotropic magnetic characteristics of permalloy sheets. These characteristics were measured using a two-dimensional single sheet tester (2D-SST). A high-precision measurement system was developed, comprising a 2D-SST (to generate two-dimensional magnetic fields and sense the induced B and H signals) and a control system (to apply in-phase 2D excitation signals and amplify, filter, and record the B and H data). Hysteresis loops were tested at low frequencies (0.1-9 Hz) and under different magnetization states (0.1-0.6 T) in two orientations-parallel and perpendicular to the annealing magnetic field-to verify anisotropy under varying conditions. Initial permeability, near-saturation magnetization, and basic magnetization curves (BM curves) were measured across different directions to provide parameters for simulations and theoretical calculations. Based on these measurements and finite element simulations, a mathematical model was developed to adjust the empirical coefficient λ used in theoretical SF calculations. The results revealed that the ratio of empirical coefficients in different directions is inversely proportional to the ratio of magnetic permeability in the corresponding directions. A verification group was established to compare the original model and the modified model. The mean squared error (MSE) between the original model and the finite element simulation was 49.97, while the MSE between the improved model and the finite element simulation was reduced to 0.13. This indicates a substantial improvement in the computational accuracy of the modified model.

DETERMINATION OF OPTIMAL CONDITIONS FOR HERMETIC WELDING OF THIN FOILS WHEN USED IN MEMBRANE-TYPE STRUCTURES

Purpose. Development of optimal technology for welding thin-walled shells mode of 12Х18Н10Т steel (δ=0.15 mm), working at alternating loads. Research methods. Research methods. For welding automatic argon-arc welding (AAAW) equipment was used for of orbital welding, which includes a MW 2600 current source (FRONIUS) with software control unit and welding head of closed type MW40. Research warks showed that this type of welding is not enough for such small thicknesses concentration of the welding arc, which does not allow stable forming of the bath and obtaining solid uniform seam. A special robotic complex was used for microplasma welding STARWELD 190H, which includes: a power source for the regular arc INV 50; source main arc power supply INV 190; SIEMENS Simatic S 7-300 control unit; robot CR3-535M (MITSUBISHI); manipulator and HPH 80 plasmatron. Welding quality control was carried out by visual inspection and metallographic examination. Taking into account the conditions of operation of the parts, according to the technical conditions of the drawing, it was also provided pneumohydraulic control method. Obtained results. Visual inspection the outer surface of the welds showed the absence of defects in the form of pores, cracks, shells, no fusions, undercuts, etc. The geometric dimensions of the weld met the requirements of the standard documentation valid at the enterprise. Metallographic studies of the boxes membranes, welded by microplasma welding, gave a positive result. Defects of metallurgical character were not found in the welds. Practical value. The optimal method of welding that can be applied is determined for the manufacture of thin-walled membrane structures, from the point of view of manufacturability and economy expediency It has been established that microplasma welding allows obtaining a hermetically tight seam, when the thickness of parts to be welded is about 0.15 mm. The performance of welded membrane boxes is confirmed in the barostatic valve of an aircraft engine. It is established that micro plasma welding can be used in the manufacture of thin-walled shells made of 12X18H10T steel (δ=0.15 mm), which work at variable loads. The technological process of welding is introduced into the series production.

Influence of Current Welding on Mechanical Properties and Microstructure of Argon Arc Welding of Type-304L Austenite Stainless Steel

Influence of Current Welding on Mechanical Properties and Microstructure of Argon Arc Welding of Type-304L Austenite Stainless Steel

Possibility of application of the ARDS method for obtaining permanent joints of composite materials reinforced with highly dispersed phase of titanium carbide obtained on the basis of aluminum-magnesium alloys

Subject of research: the evaluation of the possibility of using the argon arc welding method (ARWM) to obtain unbreakable joints of composite materials AMg2-10%TiC and AMg6-10%TiC. Purpose of research: obtaining welded joints by argon-arc welding with a non-consumable electrode based on aluminum matrix composite materials AMg2-10%TiC and AMg6-10%TiC using filler rod grade 5356 and comparing the structure and properties of AMKM welded samples with welded samples of AMg2 and AMg6 matrix alloys obtained using the same methods modes. Methods of research: studies were carried out to control visible and hidden defects, metallographic analysis, as well as an assessment of the mechanical properties of welded joints. It has been established that the level of ARDS weldability of composite materials AMg2-10%TiC and AMg6-10%TiC is at the level of ARDS weldability of matrix alloys AMg2 and AMg6. Main results of research: it is shown that when using the ARDS method it is possible to dislocate reinforcing particles of titanium carbide in composite materials AMg2-10%TiC and AMg6-10%TiC from the base metal zone to the heat affected zone as well as to the weld zone. It was found that the presence of welded joint in composite material AMg2-10%TiC leads to an increase in hardness and yield strength.

Дослідження технології зварювання плавленням складнолегованих титанових сплавів

The subject of this article is peculiarities of weld seam formation of complex titanium alloys during electron beam welding in vacuum and argon arc welding. The purpose of this study is to ensure the required level of mechanical properties of welded structures from complex titanium alloys to improve the structure and properties of welded joints. The task: to investigate the processes that are taking place in the zone of thermal influence and to determine their influence on defects formation; to determine the modes of parts welding made of complex titanium alloy; to study the effect of electron beam welding on the materials properties, such as strength, crack resistance, and corrosion resistance. Research results. The thermal cycle influence of welding and subsequent heat treatment on the structural and phase transformations in the weld metal and the heat-affected zone of complex titanium alloy welded joints was studied. It was established that a structure with a metastable β-phase predominance is formed in the weld metal and the zone of welded joints thermal influence, which contributes to the reduction of plasticity and impact toughness. The best combination of the studied welded joint strength and ductility was obtained after heat treatment, annealing at a temperature of 950 °C for 1 h, and cooling in the furnace. The use of filler wire contributes to obtaining an almost uniform structure and the disintegration of metastable phases in the seam as well as in the zone of thermal influence, and the strength limit is 1250 MPa. Conclusions. The influence of filler wires on the obtained samples structure and properties was studied, and the results were discussed depending on possible practical implementations. This article describes the creation and testing of elements of electron beam welding of complex titanium alloys technological process. This makes it possible to widely use welded combined titanium alloys in products of the appropriate purpose. The obtained scientific and practical results lead to increased mechanical properties of complex titanium alloys welded joints to the level of the base metal.

Physical and Mechanical Properties of Butt Welded Joints of Aluminum Alloys

Along with the improvement of joining technologies with argon arc, plasma and laser welding for aluminum alloy elements, high efficiency of joints made with the use of friction stir welding (FSW), which has low energy consumption and is almost equally strong as base metal, has been achieved. However, the processes of friction stir welding have not been sufficiently studied and can lead to softening of aluminum alloy welds up to 0.65 of base metal strength. When studying the effect of friction stir welding and mechanized electric arc welding in argon medium, welded joints of aluminum alloys of Al-Si-Mg (AD35T1, 6082-T6) and Al-Zn-Mg alloying systems (1915T) were subjected to tensile and impact tests. The values of strength, elastic and plastic characteristics of argon arc welded specimens of 1915T, AD35T1 and 6082-T6 alloys were obtained. For alloy 6082-T6, the same characteristics are presented for FSW welded specimens. Decrease in strength and ductility in the zones of welded joints for both welding methods is observed. At the same time, the highest relative values of strength and offset yield strength of the welded joint are fixed for friction stir welding. Slight decrease in modulus of elasticity obtained for argon-arc welded specimens was recorded. The impact strength is constant for each welded joint zones in the temperature range of +20 – -60оC and increased in weld metal of FSW butt joints of alloy 6082-T6.

Stabilization of the Ba4Y3F17 phase in the NaF-BaF2-YF3 system

The paper describes the study of the phase formation in the NaF-BaF2-YF3 system. It involved solid-phase sintering of the components in a fluorinating atmosphere at 750 °C for two weeks and quenching them in liquid nitrogen. The prepared samples were placed in nickel capillaries, which, together with barium hydrofluoride, BaF2·HF, were placed in copper containers. The containers were sealed by argon arc welding. The fluorinating atmosphere was created by pyrolysis of barium hydrofluoride, BaF2·HF. X-ray powder diffraction was carried out using a Bruker D8 Advanced diffractometer (CuKa‑radiation). TOPAS, DifWin, and Powder 2.0 software were used to process X-ray diffraction patterns. Sodium fluoride is a good sintering additive, its introduction in the amount of 5 mol % NaF was enough to synthesize sintered mass with clear X-ray diffraction patterns. The experiment revealed the formation of a solid solution based on the Ba4Y3F17 compound with a trigonally distorted fluorite structure (space group R-3) with a content of up to ~ 20 mol % of NaF. The parameters of the trigonal cell were related to the parameter а0 of the fluorite subcell by the ratios а ~ √7/2а0 and с ~2√3а0. The general formula for the resulting solid solution is Ba1-x-yYxNayF2+x-y. The introduction of sodium fluoride reduced the parameters of the trigonal lattice and was accompanied by the formation of anion vacancies. Structure stabilizationexpressed in the expansion of the homogeneity region of the phase based on Ba4Y3F17 seems to be associated with the disappearance of interstitial fluorine ions surrounded by anions in the Ba4Y3F17 structure, both in the cuboctahedral cavity of the Y6F36 clusters and in the centre of the F8 cubes. The corresponding solid solution can be used to create new photonics materials. The NaF-BaF2-YF3 system is similar to the previously studied NaF-BaF2-GdF3 system

Development of a novel fabricating thin-walled TA2 titanium tube via high-frequency induction welding

Due to the problems of low welding efficiency, large heat-affected zone, and poor welding quality in the process of welding thin-walled titanium tubes by argon arc welding, there are few studies on the use of high-frequency induction welding (HFIW) of thin-walled titanium alloy tubes. The evolution law of weld microstructure and mechanical properties of the thin-walled titanium tube needs to be further studied because of rapid welding speed and the small heat-affected zone of HFIW. Therefore, a novel manufacturing method via high-frequency induction welding is proposed in this paper to solve the existing problems. With an industrial-grade titanium TA2 tube (wall's thickness is 0.5 ​mm) as the research object, a comparative study is conducted in this research to examine the morphology, microstructure, microhardness, and tensile characteristics of welded joints at different welding power. The findings demonstrated a significant efficacy of HFIW in resolving these challenges. The mechanical properties and microstructue of heat-affected zone (HAZ) were characterized. The lowest hardness is measured at 202 HV, while the base material was recorded as 184 HV, when the welding speed of HFIW is set at 50 ​m/min. Meanwhile, the heat-affected zone has the highest hardness at 224 HV, a tensile strength of 446.8 ​MPa and a post-fracture elongation of 16%. The results showed that HFIW can not only greatly improve the welding efficiency, significantly improve the microstructure of weld joint and HAZ, and improve the mechanical properties of thin-walled titanium pipe, but also provide a highly feasible welding method for welding ultra-thin-walled pipes.

Санітарно-гігієнічна оцінка шуму при механізованому аргонодуговому зварюванні неплавким електродом алюмінієвих сплавів

Санітарно-гігієнічна оцінка шуму при механізованому аргонодуговому зварюванні неплавким електродом алюмінієвих сплавів

Technological features of fusion welding of Al – Mg system alloys rationally alloyed with scandium

The results of the formation of macro- and microstructure of welded joints of aluminum alloy sheets of the Al– Mg–Sc system obtained by automatic argon-arc and electron-beam welding are presented. The mechanical characteristics of welded joints and weld metal under the types of welding used are given. Satisfactory weldability of the studied alloy by fusion welding methods is established with the provision of strength properties of welded joints at the level of 0.8...0.85 of temporary resistance of the base metal. The effect of the welding direction in relation to the rolling direction of the sheets on the mechanical properties of welded joints is studied. The destruction of welded joints during the tests occurred in the metal and fusion zone. The fractures are of a macro viscous nature with a viscous pit micro mechanism of destruction. The strength factor of welded joints of aluminum V-1579 alloy is at the level of 0.89 for automatic argon arc welding and 0.79 for electron beam welding.

Особенности формирования сварных соединений алюминиевого сплава АК9, полученного селективным лазерным плавлением

The problem of obtaining high-quality plate welds made of AL9 alloy and powder by selective laser melting is viewed. Welded butt joints of plates of AK9CH alloy with a thickness of 3.0 mm were made by melting welding (automatic argon arc and electron beam welding) and friction stir welding. After welding the base metal of the AK9 alloy plates and their welded joints were subjected to X-ray transmission, computed tomography, metallographic analysis and mechanical tests for static tension and static three-point bending. X-ray inspection of welded joints made by automatic argon arc and electron beam welding revealed multiple porosity inside welds. The nuclei of pores in the weld metal are spherical micropores, formed in the parent metal during selective laser melting. The diameter of these micropores is 150...200 microns. In the welding bath during fusion welding, micropores develop up to 420...1070 microns in diameter in case of argon arc welding and 215...420 microns in case of electron beam welding. Metallographic analysis of cross-sections of welded joints performed by fusion welding revealed a characteristic pore distribution in the weld metal. So in case of argon arc welding, the largest pores were located near the front surface of the weld. In the fusion zone at the border of the weld and the base metal, pores with a diameter of 80.220 microns were located in the form of chains along the entire thickness of the plates being welded. When testing welded joints for static tension, the destruction of joints occurred precisely in this zone. The strength coefficient of the AK9 alloy joints obtained by fusion welding is as follows: for automatic argon arc welding 0.46, for electron beam welding - 0.66. It is established that the problem of porosity of welded joints is eliminated when using solid -phase welding for jointing (friction stir welding). The strength coefficient of the jointing of the AK9CH alloy plates made by friction stir welding is at the level of 0.81.0.86 of the time resistance of the base metal. The destruction of welded joints occurs along the mixing zone. In the weld zone during friction stir welding, as a result of dynamic recrystallization, a fine-grained equiaxed structure with an average grain size of 4.5...6.2 microns was formed with virtually no pores. The parent metal is represented by a cellular structure in which there are pores up to 168 microns in size.

A study on as-welded microstructure and mechanical properties of thick-walled 9Cr3W3Co1CuVNbBN martensitic steel weldment

A systematic study on the microstructure evolutions and their relationships with mechanical properties of thick-walled 9Cr3W3Co1CuVNbBN martensitic steel pipe joint welded by narrow-gap automatic argon arc welding was carried out. The results showed that a narrow equiaxed grain zone (EGZ) and a significantly wide inter-critical zone (ICZ) were formed in the heat affected zone (HAZ) due to the larger grain size and lower VN precipitates in base metal (BM). The refined grains formed in WM and the higher solid solubility of C, Cr and W in EGZ and ICZ were the main factors leading to their higher hardness than that of BM. The decrease of dislocation density in over-tempered zone (OTZ) immediately adjacent to ICZ not only significantly improved the impact toughness of HAZ, but also led to a significantly lower hardness than that of BM. Nevertheless, the room/high temperature tensile fracture of the welded joints occurred in the BM zone, which was attributed to the cross-sectional shrinkage of the OTZ restrained by the nearby high hardness region ICZ, and the preferential formation of cavities near the coarse Cr23C6 carbides in BM.

Influence of Overheating on High-Cycle Fatigue Characteristics of the Base Metal and Weld Metal of Low-Carbon Steel Welded Joints

The results of a high-cycle fatigue testing of our samples were obtained, and a comparative assessment of the properties of the base metal and weld metal of 09G2S-type steel (13Mn6 according to the DIN17145-80 standard) before and after overheating (1200 °C, 3.7 h) was performed. The welded joints between the sheets of 09G2S steel were obtained through automatic argon arc welding. The fatigue tests were carried out under repeated tensile loading. The “maximum cycle stress—number of cycles to failure” fatigue curves of the samples were plotted. The fracture surfaces of the samples were studied, and the fatigue failure mechanisms were analyzed. It was shown that, during testing, all samples demonstrated cyclic hardening behavior. The samples of the base metal as delivered had the highest endurance limit, and the smallest endurance limit was found in the samples of the base metal and weld metal after overheating, the endurance limits of which were similar. The fracture mechanism of all samples was quasi-brittle with the presence of very thin fatigue micro-grooves. The final rupture of all samples had a ductile dimple type.

Mathematical Modeling of the Argon Arc Welding Process. Part 2. Welding of HP40NbTi Alloy Pipelines

Mathematical Modeling of the Argon Arc Welding Process. Part 2. Welding of HP40NbTi Alloy Pipelines

Mathematical Modeling of the Argon Arc Welding Process. Part 1. Thermomechanical Approach and Model Justification

Mathematical Modeling of the Argon Arc Welding Process. Part 1. Thermomechanical Approach and Model Justification

Unusual ablation behaviors of tungsten graded network reinforced copper composites synthesized by 3D printing and infiltration sintering at ultra-high temperatures

Tungsten network reinforced functionally graded copper composites were prepared using an integrated 3D printing and infiltration technology to improve high temperature ablation properties of nuclear fusion divertor materials. The composites' ablation behavior was systematically investigated using an argon arc welding torch. Results showed that mass loss of composites was increased firstly but then decreased with the increase of ablation time. During ablation, evaporation of the melted copper reduces the local temperature of tungsten skeleton, whose high melting point also restrict the further evaporation of copper. These mechanisms significantly improve the ablative resistance of CuW gradient composite. Tungsten twinning structures were identified to form during ultra-high temperature (at 6273.15 K) ablation process in a cold environment in air. The formation of distinctive W twinning structures and gradient distribution of copper and tungsten skeleton were identified as the key mechanisms for the significantly enhanced ablation performance of the graded composite.

Individual Effects of Alkali Element and Wire Structure on Metal Transfer Process in Argon Metal-Cored Arc Welding.

This study aimed to clarify the effect of wire structure and alkaline elements in wire composition on metal transfer behavior in metal-cored arc welding (MCAW). A comparison of metal transfer in pure argon gas was carried out using a solid wire (wire 1), a metal-cored wire without an alkaline element (wire 2), and another metal-cored wire with 0.084 mass% of sodium (wire 3). The experiments were conducted under 280 and 320 A welding currents, observed by high-speed imaging techniques equipped with laser assistance and bandpass filters. At 280 A, wire 1 showed a streaming transfer mode, while the others showed a projected one. When the current was 320 A, the metal transfer of wire 2 changed to streaming, while wire 3 remained projected. As sodium has a lower ionization energy than iron, the mixing of sodium vapor into the iron plasma increases its electrical conductivity, raising the proportion of current flowing through metal vapor plasma. As a result, the current flows to the upper region of the molten metal on the wire tip, with the resulting electromagnetic force causing droplet detachment. Consequently, the metal transfer mode in wire 3 remained projected. Furthermore, weld bead formation is the best for wire 3.

Показатели свариваемости при сварке плавлением перспективных алюминиевых сплавов на основе системы Al–Ca–Zn–Mg

The results of a study of the welding properties of new aluminum alloys Al–1,0Ca–5,5Zn–1,5Mg–0,5Mn and Al–2,0Ca–2,5Mg–0,4Mn are presented. The mechanical properties of the studied alloys in argon arc and laser welding are determined. The power of Al-1,0Ca–5,5Zn–1,5Mg–0,5Mn and Al–2,0Ca–2,5Mg–0,4Mn alloys to the formation of pores in the seam in fusion welding is viewed.

ІМПУЛЬСНІ СТАБІЛІЗАТОРИ ГОРІННЯ ДУГИ ПРИ ЗВАРЮВАННІ ЗМІННИМ СТРУМОМ ПРОМИСЛОВОЇ ЧАСТОТИ

The work deals with the development of AC welding arc stabilization devices that provide a qualitatively different level of functionality to industrial frequency welding transformers. It is shown that despite the rapid spread and use of inverter sources of direct current for arc welding of metals, welding with alternating current, using simple and unpretentious welding transformers, which work at the frequency of the current of the industrial power supply network, continues to be relevant. With regard to manual arc welding with coated electrodes and a non-fusible electrode on alternating current of industrial frequency, the problem of increasing the stability of arc burning is solved thanks to the use of impulse stabilizers of arc burning. Thepurpose of the study is to increase the energy efficiency of industrial frequency alternating current welding power sources due to the development of arc stabilization devices at the modern level.The choice of the polarity of the pulses significantly affects the parameters of the stabilizing device and the AC welding process. Studies of the influence of the pulse polarity on the parameters of the pulse arc stabilizers themselves have been carried out. The schematic implementation of stabilization devices using stabilizing pulses, the polarity of which is opposite to the polarity of the arc current, is considered.The experience of using the developed stabilizers allows us to conclude that they provide sufficiently high stability of arc burning from an alternating current welding transformer during manual arc welding of low-alloy structural steels covered with electrodes, arc welding of stainless and other special steels, arc welding of cast iron, during non-fusible argon arc welding electrode of stainless steels, aluminum and its alloys with the contact method of initial ignition of the arc