最新刊期
期 5 ， 2022
- 摘要：As a basic process, welding is widely used in various fields of industrial manufacturing. Arc light, electromagnetic radiation, toxic gas and smoke particles generated during welding and its operation not only pollute the environment, but also cause great harm to the health of employees.Welding fume is an associated hazard with the most complicated impact on health and environment in welding production and the most difficult to control.Therefore, the research on welding fume control have great significance to the welding production environment and the health of employees.This paper reviews the formation mechanism, harm and control measures of welding fume. The problems existing in welding fume control in engineering application are analyzed, and the development direction of welding fume control is pointed out.关键词：welding fumes;production environment management;occupational health;hazardous factors;green manufacturing
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发布时间：2022-06-08 - 摘要：The behavior of keyhole and weld pool in laser welding is directly related to the formation of welding defects and welding quality. The study of keyhole and weld pool behavior in laser welding is of great significance to understand the mechanism of laser welding and control the welding quality. According to the physical phenomena and test data in the welding process, scholars at home and abroad put forward the corresponding mathematical models and calculation methods to simulate the flow behavior in the molten pool, the evolution behavior of the keyhole and the dynamic behavior of the internal metal vapor. Through the numerical simulation technology of laser welding molten pool behavior, it was possible to predict in advance and took corresponding measures to reduce the formation of welding defects. This would help to improve the weld quality of laser welding. This paper analyzed and summarized the research status of numerical simulation technology of laser welding pool behavior at home and abroad, such as laser deep penetration welding, double beam laser welding, vacuum laser welding, laser welding under magnetic field and laser welding with liquid metal. In order to provide reference for the research in numerical simulation of laser welding molten pool.关键词：laser welding;molten pool;numerical simulation;porosity;fluid flow
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发布时间：2022-06-08 - 摘要：Various air treatment modes of the current welding workplace are comprehensively evaluated. Based on the traditional overall workplace air treatment concept, the distributed overall workplace air treatment system is developed，according to the personalized needs of users and at the expense of certain comfort functions. The distributed overall workplace air treatment system is specially designed for welding and other hot process workshops. It uses the concept of stratified air supply of the overall workplace, adopts a group of small integrated air treatment units. It truly realizes the zoning air treatment of the whole workshop, through networking centralized control and zoning joint control. At present, the distributed overall workplace air treatment system has been successfully applied in practical projects. Due to the sacrifice of some comfort functions, the overall investment cost is reduced by more than 20%, which has good popularization and application value. In the future, the post fresh air, auxiliary heating and other functions will be intraduced into the distributed overall workplace air treatment system according to the actual application. This will be further strengthen the adaptability of the distributed overall workplace air treatment system and make the products more vitality.关键词：welding;stratified air supply of overall workplace;distributed overall workplace air treatment;pollutant
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发布时间：2022-06-08 - 摘要：This paper points out that the main concerns of environmental and health of welding machine in recent years are energy utilization rate, electromagnetic compatibility and electromagnetic field, smoke and dust. In view of the energy utilization rate of electric welding machine，it sketches out the process of the standard"The energy efficiency limit value and energy efficiency grade of electric welding machine" passed and promulgated by the nation, and a series of action and requirements for promoting the energy saving of electric welding machine are presented. In view of electromagnetic compatibility and electromagnetic field, this paper analyzes the influence on other products and human body, summarizes some international standards and requirements for electromagnetic compatibility and electromagnetic field, and summarizes four relevant standards issued by China for welding machine electromagnetic, and analyzes the direction of the four standards for welding machine respectively. For smoke and dust hazard occurring in the process of welding, smoke and dust self-priming welding machine and matched smoke and dust purifier, and other products appeared in the market, the relevant standard shall not apply to the using range and products. According to the problem，Chengdu Sanfang Electrical Company Limited put forward the method of integrating welding smoke volume by using smoke detector to improve the accuracy of suction rate detection results with the product characteristics. And jointly verify the method with a number of enterprises. If the verification reaches the expected results, it will apply for the formulation of relevant standard of suction rate.关键词：energy efficiency;electromagnetic;smoke;the smoke self-absorption welding gun
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发布时间：2022-06-08 - 摘要：Aluminum and steel composite structure is one of the effective ways to achieve lightweight carriers, in order to guide the industrial application of aluminum and steel friction stir welding technology, aluminum and steel dissimilar materials must be carried out friction stir welding process tests. The friction stir welding technology is used for the butt welding of 2.8 mm thick Q235 cold-rolled steel and 2.9 mm thick 5A06 aluminum alloy dissimilar metals, the study of the macroscopic morphology, microstructure, composition, microhardness and fracture appearance of the joint. The results show that the C shape interface concave depth and interface IMC layer thickness increase with the increase of rotational speed; a large number of Al3Ni particles diffusely distribute in the weld; at a rotational speed of 420 r/min, the interface IMC layer is 1.3μm thick FeAl phase, the joint is mainly fractured in the weld core zone and the fracture mode is ductile fracture, the average tensile strength of the joint is 240.3 MPa, the forward bending angle is 19.3° and back bending angle is 13.4°; the microhardness of the joint asymmetrically distributes and shows step characteristics.关键词：dissimilar metals;wire-filler friction stir welding;rotational speed;mechanical property;intermetallic compound
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发布时间：2022-06-08 - 摘要：The fume produced during GMAW welding with non-copper coated wire have been detected with fume detection device hereby, and its welding arc stability and wire feedability have also been checked with welding current waveform device, while the feeding force to drive the wire during welding have been tested with wire force dynamometer. The test results show that comparing with copper coated wire, the non-copper coated wire can bring many benefits, including less fume produced, more stable arc and less feeding force required, less welding spatters produced during process, and better weld appearance. Meanwhile, there are many common issues during robotic GMAW welding process such as instable arc, erratic wire feed and poor wire feed, these issues have been observed and analyzed, corresponding method on how to improve that have been discussed.关键词：non-copper coated wire in drum package;robotic welding;welding fume;spatters
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发布时间：2022-06-08 - 摘要：With the rapid development of manufacturing industry, welding technology has become one of the indispensable material processing methods. The fume generated from the base material and welding wire during the welding process of steel structures contains the toxic element of hexavalent chromium [Cr(Ⅵ)], which can seriously endanger the health of workers and cause various respiratory diseases. Therefore to carry out the work of reducing the Cr (Ⅵ) content in the fume is not only an important way to ensure the health of welders, but also the key to the development of green welding materials. This paper reviews the formation mechanism, hazards and management measures of Cr(Ⅵ) in welding fume, and analyzes the problems of Cr(Ⅵ) in welding fume management in actual production. Points out the research difficulties and future development direction of welding fume generated by steel structure base material and welding material.关键词：welding fume;hexavalent chromium;welding process;welding materials
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发布时间：2022-06-08 - 摘要：This paper analyzes the causes of suffocation and death accidents caused by the back argon filled protective welding method used by the welders in the installation of underground pipelines, also the causes of welding occupational diseases caused by the welders' long-term welding. Aiming at the welding process, The paper analyzes the occupational injury factors of harmful gases 、smoke and dust produced by high temperature in the welding process, which puts forward the suggestions of paying attention to the improvement of labor intensity, optimizing welding process, monitoring and controlling environmental harmful factors Realize personal prevention and medical protection, strict process discipline welding, eliminate and improve occupational health awareness, analyze hidden dangers and take treatment measures, so as to ensure the prevention and control methods of occupational health. The correct application of safety control methods can effectively prevent occupational health accidents of welders。关键词：nuclear power engineering site;typical welding events;occupational health prevention;control
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发布时间：2022-06-08 - 摘要：A low heat input and precise fusing amount control process-CMT is developed by Fronius, which combines the precise energy control of the power supply and the "splash-free arc ignition" welding wire feeding and withdrawing technology. CMT high-quality cladding coatings have many characteristics such as low dilution rate, high corrosion resistance, less welding deformation, and beautiful weld surface quality. CMT Advanced, CMT Pulse and CMT Pulse Advanced are further derived from the combination of variable polarity of welding current and bidirectional movement of welding wire. Ultra-thin plate, large gap and even uneven gaps can be implemented due to CMT variable polarity technology. CMT Pulse Advanced combines variable polarity with pulsed GMAW, which enables more precise heat input control, excellent gap bridging capabilities and higher cladding efficiency etc. Consequently, a variety of dissimilar metal parts can be welded. CMT is also used for the manufacture, maintenance and repair of aerospace structural components such as Mg alloy and Al-Li alloy. CMT shows advantages in metal plane printing and arc additive manufacturing applications. CMT pins can be used to connect metals and non-metals such as rubber, plastic or wood. The welding wire of TPSi-CMT welding machine can also be used as a touch sensor. The development trend of CMT welding technology is prospected, which has a certain reference value for the subsequent application and research of this technology.关键词：variable polarity;CMT arc additive manufacturing;CMT pin;CMT wire sensor
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发布时间：2022-06-08
Important Issuse
- 摘要：In order to realize high-frequency pulse bias with steep rising and falling edges and improve the quality of high-frequency pulse electron beam, a main circuit structure of series connection of base value bias DC power supply, pulse bias DC power supply and high-voltage chopper main circuit is proposed. The high-voltage chopper main circuit converts the pulse bias DC power supply into high-frequency pulse bias output through MOSFET power switch on and off, which make the pulse bias has rapidly changing rising and falling edges; Based on the working principle of modulation and demodulation, a high-voltage isolated communication power supply is designed to realize the reliable transmission of high frequency pulse bias parameters such as pulse frequency and duty cycle and commands from low voltage circuit to high voltage chopper circuit and generate the PWM waveform; A special high-voltage isolated power supply is designed to realize the reliable power supply and drive of the high-voltage chopper circuit at the high-voltage end. Based on the above technology, a high-frequency pulse electron beam bias power supply is developed, and a high-frequency pulse bias output with steep rising and falling edges is obtained. The rising edge of pulse bias is not more than 1 μs at 20 kHz.关键词：electron beam;pulse;high frequency;bias power supply;modulation and demodulation
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发布时间：2022-06-08 - 摘要：Shipyards have previously used flame heating processes to level decks, which are prone to fires and have low leveling efficiency. The induction heating leveling process adopts an induction heating leveling machine to convert three-phase sine wave high-voltage small-current alternating current(AC) into single-phase high-frequency rectangular wave low-voltage high-current AC, and through electromagnetic and magnetoelectric conversion to produce eddy current heat and hysteresis heat in the steel plate to quickly, accurately and controllably heat specific areas of the deck. The induction heating leveling machine is composed of a fixed power regulator, a mobile frequency regulator and a trolley-type induction heater connected in series through cables, which breaks through the technical bottleneck that high-frequency, low-voltage, and high-current AC power cannot be efficiently transmitted over long distances. The frequency tracking, regulation and phase locking technology of the frequency converter was developed, which ensures the quasi-pure resistive state of the output circuit so as to efficiently utilize the grid power. A trolley type induction heater was designed, which can be moved to any area as required to carry out the leveling process and the parameters can be adjusted nearby. Laboratory tests and shipyard applications show that the electrical energy conversion and energy transformation system of ship deck induction heating leveling machine is stable and reliable, and can always ensure that the leveling machine works in a quasi-resonant state and the output power factor of the induction heater is close to one.关键词：ship deck;induction heating;leveling;quasi-pure resistive state;quasi-resonant state
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发布时间：2022-06-08
Welding Equipment
- 摘要：Directed by the National Welding Standardization Technical Committee, Harbin Welding Institute Limited Company is responsible for the revision and formulation of GB/T 3670—2021 Covered Electrodes for Manual Metal Arc Welding of Copper and Copper Alloys, GB/T 41110—2021 Tubular Cored Electrodes for Gas Shielded and Non-gas Shielded Metal Arc Welding of Nickel and Nickel Alloys, GB/T 41111—2021 Rods for Gas Welding of Non-Alloy and Creep-Resisting Steels and GB/T 41112—2021 Solid wire electrodes, solid wires and rods for fusion welding of magnesium and magnesium alloys. These four national standards were issued on December 31, 2021 and will be formally implemented on July 1, 2022. Covered electrodes for manual metal arc welding of copper and copper alloys is the second revision. This revision has been converted into the ISO system, and the designation has been reformed. The structure has been greatly adjusted, and the technical content has changed a lot. Tubular cored electrodes for gas shielded and non-gas shielded metal arc welding of nickel and nickel alloys, Rods for gas welding of non-alloy and creep-resisting steels and Solid wire electrodes, solid wires and rods for fusion welding of magnesium and magnesium alloys are formulated. They are converted according to the corresponding ISO standards which the main technical content is the same as. The standard structure has been adjusted according to the domestic usage. These standards make up the blank of the national standard, and provide important technical support for the research and development, manufacturing and re-inspection of welding materials. This paper introduces the revision of the standard system from the designation and technical requirements, and compares and analyzes with the corresponding national standards abroad, so that users can better understand, master and implement the new standards.This paper introduces the situation of revising and formulating the standard, so that users can better understand, master and implement the new standards. Structural adjustment is big, technical content changes much.关键词：covered electrodes of copper and copper alloys;tubular cored electrodes of nickel and nickel alloys;rods for gas welding;solid wire electrodes of magnesium and magnesium alloys;national standards
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发布时间：2022-06-08
Welding Material
- 摘要：Inertia friction welding，as a typical solid phase welding process, has been used more often in welding fan, compressor and turbine rotating components of foreign advanced aircraft engine because of excellent welding performance. It replaces the original bolted structure, effectively reduces the manufacturing cost, reduces the engine weight and improves the thrust-to-weight ratio. At present, the foreign and domestic scholars research the inertia friction welding process and numerical simulation of aircraft engine with titanium alloy, high temperature alloy and powder metallurgy superalloy. The gap of inertia friction welding technology is pointed out by analyzing and summaring the research and application status at foreign and domestic. It will promote the domestic research work of inertial friction welding technology, improve the research level of inertial friction welding technology, and support the development of advanced aero-engine.关键词：inertia friction welding;commercial aircraft engine;titanium alloy;high temperature alloy;disparity
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发布时间：2022-06-08 - 摘要：Laser additive manufacturing and hot rolling composite manufacturing of titanium alloy parts can effectively improve the utilization rate of raw materials and improve the production efficiency of the whole parts. In this paper, TC4 was deposited on TC4 hot-rolled sheet by laser coaxial powder feeding technology, and the microstructure and properties of TC4 samples were analyzed by stereo microscope, optical microscope, scanning electron microscope, Vickers hardness tester and universal testing machine. The results show that there are hot rolled plate region, bonding region and deposition manufacturing region in the composite fabricated TC4 samples. The hot rolled plate region and bonding region are mainly composed of equiaxed grains, while the deposition manufacturing region is composed of epitaxial columnar grains. The Vickers hardness of bonded area is about 375 HV, which is slightly higher than that of hot rolled area (340 HV) and deposited area (355 HV). The tensile properties of composite fabricated specimens in vertical deposition direction (1 029.0 MPa) are better than those in parallel deposition direction (955.0 MPa), and the elongation in parallel deposition direction (19.8%) is better than that in vertical deposition direction (12.0%).关键词：TC4 titanium alloy;laser additive manufacturing;hot rolling manufacturing;microstructures;mechanical properties
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发布时间：2022-06-08 - 摘要：In order to discuss the feasibility of the laser welding replacing the TIG welding, a 3mm thick GH536 superalloy was welded by these two welding methods. The microstructure, room and high temperature tensile properties, endurance properties and fatigue properties of these two kinds of joints were compared and analyzed. The results show that the one side welding both sides forming of a 3mm thick GH536 alloy can be achieved by laser welding. The laser welding can not only reduce the heat input but also increase the welding speed by five times compared with that of the TIG welding. The average tensile strengths of laser welded joints at room temperature and 1 000 ℃ is 740 MPa and 77 MPa, respectively. The endurance life of the two joints are similar, and can reach 75% of the base metal. However, the fatigue performance of the laser welded joint is better under the same condition, and the fatigue cycle time of the laser welded joint is more than twice than that of the TIG welded joint. Because of the lower heat input, the microstructure of the laser welded joint is more uniform and the grain is finer, which are the main reasons for the better fatigue property. It is indicated that the laser welding can replace the TIG welding for the 3 mm GH536 superalloy.关键词：GH536 alloy;laser welding;TIG double-sided wire filling welding;mechanical property;metallographic structure
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发布时间：2022-06-08 - 摘要：The arc crater is an inherent defect of laser welding. In order to reduce the influence of the arc crater on the formation and mechanical properties of the thin-walled girth weld joint, a laser welding butt test was carried out on a 2 mm thick 30CrMnSi high-strength steel cylinder, and the laser welding receiving arc crater was studied. The formation reasons and the influence of process parameters on the forming of the arc crater, the microstructure and mechanical properties of the weld joints of the arc segment are tested. The results show that the arc time and welding speed have a greater influence on the depth of the arc crater. When the time is 2 s, the welding speed can be increased from 1.2 m/min to 2.4 m/min at a constant speed to obtain a better arc closing section weld formation，the arc closing crater depth is 0.08 mm. The tensile test shows that the arc closing The pit has no obvious influence on the tensile strength of the welded joint, and the quality and mechanical properties of the weld meet the requirements of the first-level weld in QJ 20659-2016.关键词：laser welding;high-strength steel;girth weld;arc crater;mechanical properties
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发布时间：2022-06-08 - 摘要：The welding at the junction of the base layer and cladding layer of the stainless steel clad plate belongs to dissimilar steel welding. Its weldability is affected by various factors such as the physical properties, chemical properties, joint form and filler metal of the cladding layer and base layer, and often causes welding cracks and other problems. Through the analysis of the welding quality of the longitudinal seam of the cylinder body, the cylinder section and the circumferential seam between the cylinder section and the head in the pressure vessel, the reasons for the low qualified rate of welding of stainless steel clad plates in specific projects are explored. The specific improvement measures are proposed, such as the use of combined grooves design and changing the welding sequence. Through the implementation of improvement measures, the welding qualification rate of the pressure vessel Q345R/S31603 stainless steel clad plates in this project has been increased from 78% to 100%.关键词：stainless steel clad plate;dissimilar steel welding;qualification rate;measure
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发布时间：2022-06-08 - 摘要：Aiming at the requirements of robotic automatic welding production line for thick wall pipe butt joint of offshore platform operation and maintenance engineering pipeline. The K-TIG, high-frequency TIG and DC TIG welding and other backing welding processes, as well as the pulse MAG filling cover welding process under the condition of mixed argon shielding gas, were used to study the process adaptability of the production line. According to the relevant requirements of American Standard ASME BPVC, the weld mechanical properties and X-ray flaw detection were carried out on the weldments in the welding test, and a set of welding production process parameters that can be used in the actual welding production were developed, which laid a process foundation for the automatic welding production of pipeline.关键词：pipeline;circumferential seam;robot automatic welding;process parameters
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发布时间：2022-06-08
Welding Technology
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