1, rolling wire

Most of the wire belongs to this category, including carbon steel Welding Wire China, low alloy steel wire, alloy steel wire, stainless steel wire and wire and other nonferrous metals.

2, cast wire

Some alloys, such as cobalt-chromium-tungsten alloy, not forging, rolling and drawing, and is made by casting method. It is mainly used for manual welding surface to meet, such as antioxidant, anti-wear and high temperature corrosion resistance and other special performance requirements. The use of continuous casting and liquid extrusion can produce up to several meters of cobalt-chromium tungsten wire, tungsten wire used to automatically fill in gas shielded arc welding, in order to improve efficiency and surfacing welding quality, while improving working conditions. Cast iron welding wire is sometimes used.

3, flux-cored

Roll into a thin strip round or shaped steel tubing, filled with a certain composition of the powder, made by drawing a seam flux cored wire, or steel pipe filled with a powder made of seamless flux cored wire drawing (see Figure). This Flux Cored Welding Wires with high deposition efficiency, adaptability of steel, a short trial period, so its use and use expanded. This wire is mainly used for carbon dioxide gas shielded arc welding, submerged arc and electroslag welding. The powder composition of flux-cored electrode drugs and skin generally similar. Containing slag, making the gas composition and stability of flux-cored arc welding without shielding gas, said the self-shielded flux cored wire, for large welded structure works.

4, the cold wire EDM

Special cold welding of EDM wire coating, applied at room temperature under welding or welding with, one second after the welding wire is characterized by the temperature does not exceed 40 degrees Celsius, continuous welding without high 80 degrees Celsius. Mainly used for heat-resistant parts that do not repair, welding stoppage time, temperature is controlled at 40 degrees Celsius, 0.4-0.5 mm in thickness, the maximum not higher than 100 degrees Celsius.

Foreword

The manufacture of welding power source has been one hundred years of history into the 1960s, the rectifier element, high-power transistor (GTR), field effect transistor (MOSFET), insulated gate bipolar transistor (IGBT) and other devices have appeared , integrated circuit technology and control technology for the development of electronic welding power supply to provide a broader space, one of the most striking is the inverter welding power source.

Inverter welding power, small size, light weight, energy-saving materials, and the control performance is good, fast dynamic response, easy to implement real-time control of the welding process, the performance of great potential advantage. In the long term, the power inverter welding power source is the development direction of welding, inverter welding machine outside the development also fully illustrate this point. Present in industrial countries, manual arc welding, TIG welding, MIG / MAG welding inverter has been widely adopted. The world, several major welding manufacturers have been completed inverter welding machine product series, and as a sign of technical level

1 Development of welding inverter

Inverter is known as "tomorrow's power" and its application in welding equipment for welding equipment, has brought a revolutionary change. First, the inverter welding power source and frequency welding power than energy-saving 20 to 30, the efficiency can reach 80 to 90; Second, inverter welding power, small size, light weight, whole weight of only traditional frequency welding power rectifier 1 / 5 ~ 1 / 10, to reduce material consumption 80 to 90. In particular, inverter welding power source has the advantage of fast dynamic response, the dynamic frequency response rate than traditional welding rectifier power increase of 2 to 3 orders of magnitude, is conducive to the welding process automation and intelligent control. These are harbingers of inverter welding power source has a broad application prospects and market potential. Ago, Japan Panasonic, Osaka transformer arc welder in the company, inverter welding machine in excess of 50. Production of major U.S. manufacturers of inverter welding machine welding machine has more than 30. Other industrialized countries the development of inverter welding power source is fast.

China's research and development of inverter Welding Wire China started in the late 1970s, in the 1980s began to develop. In 1982, Chengdu Institute began a welding machine thyristor rectifier inverter type arc welding research, developed in 1983, China's first commercial station ZX7-250 inverter welding power source, and through the project The ministry identified. Subsequently, Tsinghua University, Harbin Institute of Technology, South China University of Technology and Time Inc. and other units have been introduced using a variety of switching elements of the inverter welder. Now, China has formed 4 inverter welding power generation: the first generation of power devices is the thyristor SCR-based inverter; second-generation transistor inverter; third-generation FET inverter; The fourth generation IGBT inverter, the inverter frequency is high, the saturation pressure to reduce power consumption, high efficiency, no noise, and compared to the first three-generation inverter, the advantage is more obvious.

Broad prospects for development of inverter welding machine attracted a large number of universities and research institutes. However, due to inverter welding power combined electric and electronic, in the development of the traditional test method used not only to consume a large amount of manpower, material and time, and some test methods is difficult to detect and resolve. Therefore need to propose new design methods and tools.

In recent years, circuit analysis and design methods as the use of computer simulation technology have developed rapidly. Circuit design using computer simulation techniques for different designs quickly simulation analysis, and determine the form in the circuit after the circuit component parameters for sensitivity analysis and tolerance analysis, to optimize the component parameters to ensure design quality. Therefore, the circuit design using computer simulation techniques, can greatly reduce the manual labor, shorten the design cycle, reduce design costs. At present, the study of power electronic devices, more and more devices using computer simulation techniques. For high-power welding inverter, its working environment and load conditions are very poor, while the use of the power device is very expensive, so in the welding inverter design using computer simulation techniques have more advantages.

2 computer simulation technology

2.1 Development of computer simulation technology

Computer simulation technology to the development of modern computer simulation technology and combine the system through the establishment of a mathematical model to computer as a tool for numerical computation as a means of existing or envisaged in the systems studied. In China, since the since the mid-1950s, the system simulation technology in the aerospace, aviation, military and other cutting-edge areas of applied and achieved significant results. Since the early 1980s, with a wide range of computer applications, digital simulation technology in automatic control, electrical transmission, machinery manufacturing, shipbuilding, chemical engineering technology has been widely used.

Experience with traditional methods, the advantages of computer simulation are: â‘  the computer can provide all the relevant variables within the full detailed data; â‘¡ not for system test; â‘¢ predictable changes in the process of a particular process and the final result, so that people process variation in depth of understanding; â‘£ difficulty in measurement is the only case study method. In addition, the digital simulation also has a high efficiency, high precision and the actual system is difficult to have a destructive or dangerous experimental studies, etc. BR> 2.2 Simulation Power Electronics Research

Simulation technology in the application of power electronic circuits is very important in many applications its part to carry out research in this area to become an indispensable tool. In the power electronics circuit design, computer simulation is mainly used for design verification, system performance prediction, the discovery of new products, potential problems and solutions to problems of evaluation. It is mainly to address two issues, namely how to build the circuit equations and how to solve the circuit equations.

Since the 1970s so far, circuit simulation analysis methods used are: state variable method, nodal analysis, nodal analysis method and the improved state-space averaging method. These modeling methods have their advantages and disadvantages, the use of its own, when used in concrete, according to the specific purpose of using the appropriate method to establish the specific simulation model.

For the switching converter such a strong non-linear time-varying systems, to accurately analyze the space and the dynamic performance is often very difficult. Establish a precise mathematical model of the field of power electronics has been a problem, usually only assume certain conditions, while ignoring some minor factors, can be applied within a certain range of mathematical models for circuit analysis and design help. The modeling is usually two ways: â‘  According to the device carrier movement within the physical laws to establish the physical - electrical model; â‘¡ According to the external behavior of the device to establish the equivalent macro model.

Over the last decade, many domestic and foreign scholars have done a lot of modeling of electromagnetic devices work, you first need to solve the problem is to describe the magnetic properties of magnetic materials, one of the more practical model has a clear physical meaning of the J-A model and the use of general component model constructed macro models. In the magnetic model, based on the integrated use of Faraday, Ampere and Gauss's law three major electromagnetic, electromagnetic devices can determine the magnetic circuit model. Circuit and magnetic circuit according to the principle of decoupling, you can create electromagnetic devices of the circuit model.

In short, the control circuit modeling, theoretical analysis and computer simulation technology is relatively mature, and power electronic devices and magnetic devices practical simulation models, especially for technical parameters need to be further improved.

2.2 used a variety of circuit simulation software

Commonly used in circuit simulation software Pspice, Saber, Simplis and MATLAB, etc. Usually two types of power electronic simulation software: focus on the circuit simulator and focus on the equations of the simulator, which PSPICE, Sabert and MATLAB are representative of two types of emulators.

PSPICE is one of the earlier emergence of the EDA software by MICROSIM company launched in 1985. In circuit simulation, its function can be most powerful in the country is widely used. Is now using more PSPICE6.2, working in the Windows environment, taking more than 20 megabytes of hard disk space. PSPICE can be a variety of circuit simulation, the establishment of incentives, temperature and noise analysis, analog control, waveform output, data output, and simultaneously in the same window display analog and digital circuits. No matter what kind of device on which circuit simulation, including IGBT, pulse-width modulation circuit, analog / digital conversion, digital / analog conversion, etc., can get accurate simulation results. There are no components for library modules, you can also edit their own.

MATLAB5.2 in 1998 by the Mathworks company launched, in which additional PowerSystemBlockset (PSB) under conditions of use contained in a certain component models, including the power system network components, motors, power electronics, control and measurement aspects as well as three-phase library etc., and then by means of other library or module toolkit, in the Simulink environment, power system simulation can be calculated, the control method can be complex simulation, the simulation can be observed simultaneously during the execution. Simulation results using the end of the simulation variables are stored in the MATLAB workspace.

Simulation software PSPICE and PSB have the advantage of its application, its version is also constantly updated, which PSB has now launched version 6.1. PSB for medium-scale circuit simulation, and change / fixed-step simulation algorithm for circuit simulation.

MATLAB / SIMULINK powerful computing capability for post-processing of simulation results is very convenient. PSPICE is applicable to small-scale component-level modeling system. If the system is too large, the simulation execution time is very long.

3 Computer simulation of the welding inverter application status

At present, computer simulation technology has been widely used in aviation, aerospace, military and other cutting-edge technology, has played a huge role. A few years ago researchers began welding technology it introduced to the welding power supply, has made certain achievements, but its not very in-depth research, this literature is not a lot.
From the existing literature can be seen in the simulation of arc welding inverter technology was more mature. Earliest research in this area is the China University of Technology, its commitment to the National Natural Science Foundation project "arc welding inverter structure, parameters and computer simulation aided design" is the simulation of welding equipment in the application of technology in a typical example. It takes advantage of powerful computer, through a comprehensive, systematic and in-depth qualitative and quantitative analysis, description and study of a new generation of arc welding inverter parts and core components of the work process and the dynamic response, the development of inversion theory, to solve the domestic arc welding inverter quality and reliability problems, so as to realize the computer-aided optimization of arc welding inverter design, design of electromechanical products to improve the scientific and automation.

Commonly used methods of arc Flux Core Welding Wire inverter simulation there are two: one is to create the various components in the circuit model, and then put them together into circuit simulation. If literature is to PSPICE model of the existing devices based on the establishment of the first insulated gate bipolar transistor (IGBT) a combination of model and to characterize the nonlinear capacitance of the device parasitic capacitance. And then use the established model, the double-end full-bridge zero-voltage zero-current (FB-B-ZVZCS-PWM) soft-switching converter for the computer simulation, analysis of the converter device switching performance and energy transmission performance, and through experimental verification of the simulation results confirmed the establishment of an appropriate device models based on computer simulation studies can be an effective means of arc welding inverter; Another way is to the inverter circuit as a whole simulation. Arc welding inverter according to the dynamic characteristics of the process, the use of computer simulation technology, the control system through the establishment of non-linear model, to be a direct description of dynamic processes, and simulation analysis for the study of arc welding inverter output current dynamic process to provide effective means.

Simulation always involves parameter optimization problem, the literature around the inverter main circuit design of dynamic processes, focusing on the power pulse transformer and snubber circuit design features, both qualitative and quantitative changes in device parameters of the dynamic process of the main circuit the impact of the computer-aided simulation based on the optimal design. Shenzhen University R> In addition, the persons concerned; for electric arc welding inverter dynamic model of in-depth study of the successful simulation of the dynamic characteristics of the arc graph, and analyze the dynamic characteristics of the arc and pulse multi-line diagram of the organic Contact. As the arc stability is based on the stability of the controller, so driven on the stability of the characteristic diagram of power supply design can proof correctness.

Welding transformer is the heart, is a low-voltage, high current power devices. Its performance will directly affect the quality welder. Literature] AC arc welding transformer for computer-aided design system for the study, the design of the welding transformer is divided into six parts were designed and then integrated together, that is, using the total - points - the total design, not only to improve calculation accuracy and speed, but also reduce the labor intensity and designers to reduce design costs. In addition, the transformer magnetic bias caused by magnetic saturation and inverter circuit subversion problem, the researchers through the full-bridge inverter circuit transformer magnetic saturation principle study, proposed the use of double-loop feedback control method to solve the problem. After the circuit design, simulation and waveform analysis, from the experimental point of view demonstrate the feasibility and effectiveness.

Simulation technology in inverter welding machine has also been a certain application. Engaged in this work are Harbin Institute of Technology and other Research Institute, universities, their resistance welding machine inverter circuit simulation, analysis, and design of the circuit, thereby reducing development costs and increase welding efficiency. As in other aspects of the application is relatively fragmented, less-integrated, now also is not a lot to see.

So generally speaking, computer simulation technology in the field of welding power source is a new thing, its further development takes time.

4 Problems and future direction

As can be seen from the previous description, computer simulation technology was introduced into the field of welding power source after the rapid development of welding equipment, the design of the main circuit structure, parameter optimization play an important role. Greatly reduces the design costs and shorten the design cycle, improve product reliability, showing the great vitality. However, it is undeniable, the special nature of the welding power supply itself, the current combination of computer simulation technology, there are the following issues:

(1) welding power supply system is a combination of electric and electronic strongly nonlinear systems, including electric and magnetic interactions are very complex and difficult to understand. For such a system is difficult to find a mathematical equation to be described, it is not easy with a transfer function from them on the whole simulation. Therefore, the existing simulation are mostly concentrated in its imitation of a specific part of the internal circuitry. This is not easy to test the system has been designed for complete simulation of the overall effect.

(2) the accuracy of the model components of a great influence on the final simulation results, it is essential to establish accurate component models. In the welding power supply circuit includes a large number of non-linear high-power switching components and electromagnetic devices, as previously noted in Part II as the electromagnetic components for high-power components and their modeling and parameter extraction has been difficult, to be further perfect. Therefore, if the technology can not solve the bottleneck, the simulation has been done to get the circuit being applied to the actual circuit is obviously not realistic.

(3) welding power source is a key part of the welder, but if you want to develop a high-performance, high reliability of welding, and other auxiliary parts such as drive circuit and protection circuit can not be ignored, and now the simulation is less to them as a whole to be carried out. Therefore, this needs to be strengthened.

(4) a variety of types of welding, a welding machine, resistance welding machines, laser welding, plasma welding, etc., resulting in the welding part of the main circuit power supply varies. Thus, the power to bring a specific circuit design choice.

In short, I believe that these four problems related to the welding power simulation technology can really be promoted, and how to solve these problems is the future for quite some time, the research, once these issues are properly resolved, is not difficult to imagine the for the future of. We look forward to the early technology of welding equipment to reach the world advanced level.