Welding equipment type Welding equipment type
1. Cold welder Cold welder uses the principle of high frequency electric spark discharge to weld the workpiece without heat. The cold welder can deposit, seal, and repair the defects of metal workpieces such as wear, scratches, pinholes, cracks, defect deformation, hardness reduction, trachoma, and damage. Simple operation, low heat input, no heat input during the instantaneous process of surfacing, so the mold does not deform, does not anneal, undercut and residual stress, does not change the metal structure of the mold or product, and has high repair precision, and the coating thickness ranges from a few microns to A few millimeters, only need to be polished and polished. It can also carry out various types of machining such as turning, milling, planing, grinding, etc., as well as post-processing such as electroplating.
Welding equipment
(1) Hand arc welding equipment. The equipment used for hand arc welding is simple, the method is simple and flexible, and the adaptability is strong, but the welder has high operation requirements. Hand arc welding is suitable for welding metal materials such as carbon steel, low alloy steel, stainless steel, copper and copper alloy.
(2) Submerged arc welding equipment. The submerged arc welding equipment consists of a welding power source, a submerged arc welding machine and auxiliary equipment. Its power supply can be used with AC, DC or AC and DC. Submerged arc welding machines are divided into two categories: automatic welding machines and semi-automatic welding machines. 1 semi-automatic submerged arc welding machine. 2 automatic submerged arc welding machine.
(3) CO2 gas shielded welding equipment Semi-automatic CO2 gas shielded welding equipment is mainly composed of welding power source, gas supply system, wire feeding mechanism and welding torch.
(4) Inert gas shielded welding equipment Manual inert gas shielded welding equipment includes welding torch, welding power supply and control device, gas supply and water supply system.
(5) Plasma arc welding equipment Plasma arc welding equipment mainly includes welding power source, control system, welding torch, pneumatic system and waterway system.
Welding equipment system structure characteristics
Mechanical device
The spot welder system consists of three parts: mechanical device, power supply device and control device. In order to meet the welding process requirements, the welding mechanism (welding tongs) adopts a two-stroke fast pneumatic transmission mechanism. By changing the stroke control handle to change the opening degree of the welding tongs, it can be divided into large opening and small opening to meet the welding operation requirements. The normal state is that the welding clamp is short-stroke open. When the control button is switched to the "energized" position, the handle switch is used to clamp the pressure, and the current is restored to the short stroke after completing a welding cycle under the control of the control system. Open state.
2. Power supply unit
The main power circuit is composed of a resistance welding transformer, a thyristor unit, a main power switch, a welding circuit and the like. At present, the welding equipment we use is a single-phase power frequency AC resistance welder with a power of 200kVA and a secondary output voltage of 20V. Due to the collinear production of various models, the welding tongs are to be welded with high-strength steel and low-carbon steel sheets. The welding tongs must transmit large mechanical force and welding current. Therefore, the strength, rigidity and heat of the welding tongs must meet certain requirements. It also has good electrical and thermal conductivity, and requires the welding tongs to be cooled by water. Therefore, the welding tongs can be used to withstand the new welding tongs with a pressure of 400 kg.
3. Control device
The control device mainly provides signal control resistance welder action to turn on and off the welding current, control the welding current value, and perform fault monitoring and processing.
Welding process in the development of the industry
There are more than 40 kinds of metal welding methods, which are mainly divided into three categories: welding, pressure welding and brazing. Fusion welding is a method in which the workpiece interface is heated to a molten state during welding and the welding is completed without pressure. During fusion welding, the heat source rapidly heats and melts the interface of the two workpieces to be welded to form a molten pool. The molten pool moves forward with the heat source, and after cooling, forms a continuous weld to join the two workpieces into one body. During the fusion welding process, if the atmosphere is in direct contact with the high temperature molten pool, oxygen in the atmosphere oxidizes the metal and various alloying elements. Nitrogen, water vapor, etc. in the atmosphere enter the molten pool, and defects such as pores, slag inclusions, cracks, etc. are formed in the weld during subsequent cooling, which deteriorates the quality and performance of the weld.
In order to improve the quality of welding, various protection methods have been developed. For example, gas-shielded arc welding is to insulate the atmosphere with gas such as argon or carbon dioxide to protect the arc and the molten pool rate during welding. For example, when the steel is welded, the ferrotitanium powder with high affinity for oxygen is added to the electrode coating for deoxidation. It can protect the beneficial elements of the electrode, such as manganese and silicon, from oxidation and enter the molten pool, and obtain high-quality welds after cooling.
Pressure welding is to achieve atomic bonding in the solid state under pressure conditions, also known as solid state welding. The commonly used pressure welding process is resistance butt welding. When the current passes through the connection end of the two workpieces, the temperature rises due to the large resistance, and when heated to the plastic state, the connection is integrated under the axial pressure.
A common feature of various pressure bonding methods is the application of pressure during the welding process without the addition of filler material. Most pressure welding methods, such as diffusion welding, high-frequency welding, cold-welding, etc., do not have a melting process, so there is no problem of burning of beneficial alloying elements like welding and intrusion of harmful elements into the weld, thereby simplifying the welding process. Improved safety and hygienic conditions for welding. At the same time, since the heating temperature is lower than the fusion welding and the heating time is short, the heat affected zone is small. Many materials that are difficult to weld by fusion welding can often be welded to a high quality joint of the same strength as the base material.
Brazing is to use a metal material with a lower melting point than the workpiece as a brazing material to heat the workpiece and the brazing material to a temperature higher than the melting point of the brazing material and lower than the melting point of the workpiece. The workpiece is wetted by the liquid brazing material, filling the interface gap and realizing with the workpiece. The method of mutual diffusion between atoms to achieve welding.
The seam formed by welding when joining two connected bodies is called a weld bead. Both sides of the weld are subjected to welding heat during welding, and changes in structure and properties occur. This area is called the heat affected zone. Due to different welding materials and welding currents of the workpiece during welding, overheating, embrittlement, hardening or softening may occur in the weld and heat affected zone after welding, and the weldment performance may be degraded and the weldability may be deteriorated. This requires adjustment of the welding conditions, preheating at the weldment interface before welding, welding heat preservation and post-weld heat treatment can improve the welding quality of the weldment.
In addition, the welding is a local rapid heating and cooling process. The welding zone cannot be freely expanded and contracted due to the restraint of the surrounding workpiece body, and the welding stress and deformation are generated in the weldment after cooling. Important products need to eliminate welding stress after welding and correct welding deformation.
Modern welding techniques have been able to weld welds with no internal or external defects and mechanical properties equal to or even higher than the welded joints. The mutual position of the welded body in space is called the welded joint, and the strength of the joint is affected by the quality of the weld, and also related to its geometry, size, stress and working conditions. The basic forms of the joints are butt joints, lap joints, T-joints (orthogonal joints) and corner joints.
The cross-sectional shape of the butt joint weld is determined by the thickness of the welded body before welding and the groove form of the two joints. When welding a thick steel plate, grooves of various shapes are opened at the joint edges for penetration to facilitate feeding of the welding rod or the welding wire. The groove form has a single-sided welded groove and a double-sided welded groove. When selecting the groove form, in addition to ensuring the penetration, it is also necessary to consider the convenience of welding, the small amount of filler metal, the small welding deformation and the low processing cost of the groove. When two steel plates with different thicknesses are butted together, in order to avoid severe stress concentration caused by sharp changes in the cross section, the thicker plate edges are gradually thinned to be equal to the thickness of the two joint edges. The static strength and fatigue strength of the butt joint are higher than other joints. Welding of butt joints is often preferred over joints that operate under alternating, impact, or low temperature, high pressure vessels. The pre-weld preparation of the lap joint is simple, the assembly is convenient, the welding deformation and the residual stress are small, so it is often used in the installation of joints on the construction site and unimportant structures. In general, lap joints are not suitable for operation under alternating loads, corrosive media, high temperatures or low temperatures.
The use of T-joints and corner joints is usually due to structural requirements. The work characteristics of the fillet welds that are not welded on the T-joint are similar to the fillet welds of the lap joint. When the weld is perpendicular to the direction of the external force, it becomes a front fillet weld. At this time, the shape of the weld surface will cause different degrees of stress concentration; the weld of the fillet weld is similar to that of the butt joint.
The angle joints have low load carrying capacity and are generally not used alone. They are only improved when they are welded or have fillet welds inside and outside. They are mostly used at the corners of closed structures.
Welded products are lighter in weight than rivets, castings and forgings, saving weight and saving energy for transportation. The welding has good sealing properties and is suitable for manufacturing various types of containers. The development of joint processing technology, welding, combination of forging and casting, can be made into a large, economical and reasonable cast-welded structure and forged welded structure, with high economic benefits. The welding process can effectively utilize the materials, and the welded structure can use different performance materials in different parts, giving full play to the advantages of various materials to achieve economic and high quality. Welding has become an indispensable and increasingly important processing method in modern industry.
In modern metal processing, welding is developing later than casting and forging, but the development speed is very fast. The weight of the welded structure accounts for about 45% of the steel output, and the proportion of welded structures of aluminum and aluminum alloys is also increasing.
In the future welding process, on the one hand, new welding methods, welding equipment and welding materials should be developed to further improve welding quality and safety reliability, such as improving existing arc, plasma arc, electron beam, laser and other welding energy; using electronic technology And control technology to improve the process performance of the arc and develop a reliable and lightweight arc tracking method.
On the other hand, it is necessary to improve the mechanization and automation level of welding, such as the program control and digital control of the welding machine; the special welding machine for the automation of all processes from preparation, welding to quality control; and the promotion and expansion of CNC welding on the automatic welding production line. Robots and welding robots can improve the level of welding production and improve the sanitary and safety conditions of welding.
(Plastic) Welding A method in which two or more surfaces of a thermoplastic article are fused together by heating and pressing or other means.
The automation adopts the technical measures of automatic control, automatic adjustment, detection and processing of machinery and equipment, and automatic operation according to specified procedures or instructions. Its purpose is to increase production, improve quality, reduce costs and labor intensity, and ensure production safety. The degree of automation has become one of the important indicators to measure the level of science and technology and economic development in modern countries.
Modern automation technology relies mainly on computer control technology. Welding production automation is the development direction of welding structure production technology. Modern welding automation technology will develop intelligent welding equipment based on high-performance microcomputer-controlled wave welding power supply. Based on the existing welding robot, the flexible welding station and welding production line will be developed, and finally the welding computer integrated manufacturing system CIMS will be realized.
Development of application of microcomputer automation control technology in welding equipment, such as CNC welding power supply, intelligent welding machine, automatic special welding machine and flexible welding robot workstation. The role of the microcomputer control system in various automatic welding and cutting equipment is not only to control various welding parameters, but also to automatically coordinate the actions of the various components of the complete welding equipment to achieve unmanned operation, that is, to achieve numerical control, automation and automation of welding production. Intelligent. The microcomputer-controlled welding power supply has become the basis of the automation-specific welding machine and the intelligent welding equipment. Such as microcomputer controlled thyristor arc welding power source, transistor arc welding power source, inverter arc welding power source, multi-function arc welding power source, pulse arc welding power source, etc. Microcomputer controlled IGBT inverter welding power supply is an ideal device for intelligent control
Most of the special-purpose welding machines of CNC type are automatic TIG welding machines, such as automatic tube/tube TIG welding machine, automatic tube/board TIG welding machine, automatic TIG welding machine and so on. In the welding production, it is often necessary to design and manufacture automated welding process equipment according to the characteristics of the weldment, such as welding machine tools, welding centers, welding production lines and other self-made complete sets of welding equipment, most of which can be used for general welding power supply, automatic welding head, wire feeding. Equipment, welding vehicles and other equipment combinations, and a unified computer control system to coordinate them into a whole.
Advances in welding technology will bring huge business opportunities to the welding industry
China's 2006-2020 Steel Science and Technology Development Guide clearly states that it will gradually produce high-strength, high-toughness steel with a yield strength of 400-800 MPa, tensile strength of 600-1400 MPa, and so-called 21st century super steel with an increase of 1 to 4 times the strength. . With the popularization and application of high-strength steel and ultra-high-strength steel, it will impact the traditional welding design concept. The continuous development and evolution of steel will definitely put forward new and higher requirements for steel structure welding technology.
Therefore, new steel types will emerge in an endless stream. All kinds of high-strength building structural steel, ship plate steel, pressure vessel steel, pipeline steel, bridge steel, heat-resistant steel and low-temperature steel will further sublimate along the development path of the Bird's Nest Q460E-Z35 steel, which will be refined by molten steel. Advanced technologies such as controlled rolling and controlled cooling (TMCP) will develop in the direction of low carbon, microalloying, pure and fine grain, and improve the strength and toughness of steel. This will be the basic technical route for the development of China's steel industry.
GB50661 "Steel Structure Welding Code" conforms to the development track of China's construction steel structure technology, and clarifies the types and applications of high-strength steel, so that the steel structure steel will be oriented in a more advanced direction, which will certainly promote the transformation of welded steel structure.
High-strength steel generally refers to a steel produced with a yield strength greater than 400 MPa and a yield ratio greater than 0.85, which is produced in consideration of weldability. The embrittlement of the heat-affected zone of high-strength steel microalloy controlled rolling and controlled cold steel is an important welding problem. The higher the heat input, the more serious the embrittlement tendency. The embrittlement problem of HAZ mainly includes embrittlement of coarse-grained zone (CGHAZ), embrittlement of critical heat-affected zone (ICHAZ), critical coarse-grained heat affected zone (IRCGHAZ) during multi-layer welding, and supercritical coarse-grained heat affected zone (SRCGHAZ) embrittlement and subcritical coarse-grained heat affected zone (SCGHAZ) embrittlement. Among them, embrittlement of CGHAZ, IRCGHAZ, and SCGHAZ is the most attractive embrittlement zone for microalloyed steel welding.
Due to the high-performance characteristics of high-strength steel slabs, there are high requirements for welding equipment, welding materials and cutting and welding processes, especially for the first pass rate of cutting and welding, otherwise the quality of the weld is difficult to guarantee.
There is every reason to say that the steel structure adopts high-strength steel on a large scale, which will promote the technological progress of the welding industry and create a huge leap, bringing huge business opportunities.
As we all know, a revolution will bring great changes. Various factors will lead to strong alliances of good assets and competition. Success and failure will be combined, opportunities and risks will coexist. In the face of the upcoming revolution, it takes courage to fight. And courage; strategizing, winning a thousand miles requires wisdom and resilience; catching up with the world's advanced level requires more effort and hard work. Empty talk about misunderstanding, hard work, and hope for peers.
Working principle of Panasonic argon arc welding machine
1. What is argon arc welding? The Panasonic argon arc welding machine is a tungsten inert gas shielded arc welding. It refers to a welding method using industrial tungsten or activated tungsten as an infusible electrode and inert gas (argon) for protection, referred to as TIG.
Second, the arcing mode of the Panasonic welding machine The arcing of the argon arc welding adopts the arcing mode of high-voltage breakdown. First, the high-frequency high-voltage is applied between the electrode needle (tungsten needle) and the workpiece, and the argon gas is broken to make it conductive. Supply continuous current to ensure arc stability.
Third, the general requirements of argon arc welding on the gas control requirements: the gas is required to come first and then go, argon gas is easier to be penetrated by the inert gas, first between the workpiece and the electrode needle is filled with argon, which is conducive to arcing; welding After the completion, keep the air supply, help prevent the workpiece from cooling quickly and prevent oxidation, and ensure a good welding effect.
Current hand switch control requirements: When the hand switch is pressed, the current is delayed compared to the air, the hand switch is disconnected (after the welding is finished), and the air supply current is delayed first according to the requirements.
High-pressure generation and control requirements: The argon-arc welding machine adopts the high-pressure arc-starting method, which requires high pressure when starting the arc, and the high voltage disappears after the arcing.
Interference protection requirements: argon arc welding with high frequency in the arcing high voltage, which causes serious interference to the whole circuit, requiring the circuit to have good anti-interference ability.
International welding equipment giant accelerates the pace of opening up the Chinese market
At the just-concluded 13th Beijing Essen International Welding and Cutting Exhibition, many international welding equipment giants have come to the scene. While demonstrating the latest welding equipment, processes and technologies, the Chinese market that has seized rapid economic growth has become these. One of the strategic considerations of the giants.
It is understood that the welding equipment known as "industrial sewing machine" is an important process equipment of modern industry. It is widely used in the efficient connection of metals and alloys, directly affecting the quality, reliability and life of the products as well as production cost, efficiency and market competitiveness. Driven by the sustained rapid growth of China's economy and the acceleration of industrialization, urbanization, and modernization, a number of industries, such as railways, shipbuilding, oil pipelines, construction, and automobiles, which are related to the national economy and the people's livelihood, have strong demand for steel, creating huge business opportunities for the welding equipment market.
According to experts from the China Welding Association, according to the calculation of 25 welding machines per 10,000 tons of steel, China's steel output in 2007 reached 490 million tons, requiring a total of about 1.25 million welding machines. However, limited by domestic production technology and technology, medium and high-end automatic and semi-automatic arc welding machines, resistance welding machines, special welding machines and special complete sets of equipment, which account for half of the total domestic market and worth US$1 billion, still rely on imports.
Faced with such a huge business opportunity in the Chinese market, international welding equipment giants have rushed to the market and strive to expand the market share of high-end welding equipment. Finnish Kemppi Group CEO Angxi. Rantasalo said that the development of China's welding equipment market is an important part of the company's development strategy, and will provide China with more efficient, automated, intelligent, energy-saving and environmentally friendly welding equipment through the “new welding experienceâ€.
How to choose a welding robot system
Many bosses want to automate their production lines because of market conditions. There are not many concepts and experiences for the application of automation equipment. They often make decisions based on the price of the manufacturer when purchasing equipment, and give the advantages that should have been mastered. Amateur opponents. From the perspective of choosing a welding robot welding system to explain how to make the right decision in this regard.
The welding robot system, one set can complete more than 30 products in one day. If the profit of a product is 10 yuan, then the profit for one year (360 days) will be 108,000 yuan. In this case, if the inefficient system is 100/00 yuan cheaper than the more efficient system, it is not worth buying.
The efficiency of the welding robot system can be determined from many aspects, such as welding cycle (cycle), mean time between failures, average time to failure recovery, zero recovery time, teaching time, programming time, etc. These parameters are explained and analyzed.
The length of the welding cycle (cycle) cannot be calculated from the average speed of the robot on the catalog. Because the robot must run according to the programmed trajectory throughout the welding process, the trajectory consists of many points. Because the robot's motion is controlled by a closed-loop control system, many other robotic technical parameters have a large impact on the welding tempo, such as average positioning time, rise and correction time, rate, acceleration, and so on. These parameters usually do not appear in the directory.
In addition to efficiency, the life of the equipment is also part of the cost. The longer the life of the equipment, the lower the production cost.
Another point worth considering is whether the function of the device is diversified, because the market is changing rapidly, and if the device function can be easily changed, it is more advantageous. Such as the conversion from CO2 gas shielded welding to argon arc welding, welding of stainless steel from welding stainless steel, transfer from the welding robot to carry, bending or polishing the robot.
The difference, advantages and disadvantages between domestic welding robots and imported robots
At present, the robot applications in the domestic market are mainly divided into Japanese, European and domestic. Japanese robots mainly use Yaskawa MOTOMAN, OTC, Panasonic, FANUC and other robots. Europe and the United States are Germany's KUKA, CLOOS, Sweden's ABB and Austria's IGM. The domestic robots are mainly Shenyang Xinsong robot and Guangzhou CNC. The difference and characteristics of welding robots in Europe and America. The same point: mainly used for spot welding and arc welding, can be applied to automated production lines, welding production lines. Used in many fields, including welding, handling, spraying, etc.
difference:
1, Japanese welding robots are more focused on arc welding, such as OTC, Panasonic, motoman, etc.; Europe and the United States are more focused on spot welding, such as KUKA.
2. European and American robots can be widely used in the spray industry, such as ABB.
3. Japanese welding robots are about 30% cheaper than those in Europe and America, and can be applied to most fields, which is more suitable for the domestic market.
4. Regardless of the algorithm, European and American robots have a large advantage (less than 1 ton) in terms of accuracy and load compared to Japanese.
At present, although there are already series of welding robots with independent intellectual property rights in China, they cannot be mass-produced and form scale. There are several main reasons:
There is no advantage in domestic robot prices. In the past 10 years, the price of imported robots has been greatly reduced, from $70,000 to $30,000 to $30,000, making it difficult for ordinary industrial robots made in China to compete with them. In particular, in the early stage of developing robots in China, there was no simultaneous development of the corresponding parts and components industry, such as servo motors, reducers, etc., which required the import, which made it difficult to reduce the price, so the cost of robot production could not be reduced. The level of welding equipment in China still exists very much abroad. The big gap, this also indirectly affects the development of domestic robots. For the car's largest user, the car body-in-white manufacturer, almost all of the equipment has been imported from abroad, and domestic robots can hardly find a stage for performance.
We should admit that domestic robots still have a certain gap with foreign companies in terms of control level and reliability. Foreign industrial robots are very mature industrial products. After more than 30 years of development, they are constantly improving and improving in actual production, while China is in a single-piece and small-batch production state.
Domestic robot manufacturers are in their early childhood and need government policy and funding support. The welding robot is a mechatronics high-tech product. It is not enough to rely solely on the company's own capabilities. It requires the government to give certain policies and financial support to robot manufacturers and enterprises using domestic robot systems to accelerate the development of domestic robots.
However, in welding parts with relatively simple processes, domestic welding robots have a strong competitive advantage. Moreover, the structure is simple, the skill requirements for employees are relatively low, and the repair costs are relatively low.
In the imported welding robot, complex workpiece welding can be realized, and there are strong technical requirements for operators and repairmen. The accessories are relatively expensive, and the supply of parts is difficult to be timely.
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1. Cold welder Cold welder uses the principle of high frequency electric spark discharge to weld the workpiece without heat. The cold welder can deposit, seal, and repair the defects of metal workpieces such as wear, scratches, pinholes, cracks, defect deformation, hardness reduction, trachoma, and damage. Simple operation, low heat input, no heat input during the instantaneous process of surfacing, so the mold does not deform, does not anneal, undercut and residual stress, does not change the metal structure of the mold or product, and has high repair precision, and the coating thickness ranges from a few microns to A few millimeters, only need to be polished and polished. It can also carry out various types of machining such as turning, milling, planing, grinding, etc., as well as post-processing such as electroplating.
Welding equipment
(1) Hand arc welding equipment. The equipment used for hand arc welding is simple, the method is simple and flexible, and the adaptability is strong, but the welder has high operation requirements. Hand arc welding is suitable for welding metal materials such as carbon steel, low alloy steel, stainless steel, copper and copper alloy.
(2) Submerged arc welding equipment. The submerged arc welding equipment consists of a welding power source, a submerged arc welding machine and auxiliary equipment. Its power supply can be used with AC, DC or AC and DC. Submerged arc welding machines are divided into two categories: automatic welding machines and semi-automatic welding machines. 1 semi-automatic submerged arc welding machine. 2 automatic submerged arc welding machine.
(3) CO2 gas shielded welding equipment Semi-automatic CO2 gas shielded welding equipment is mainly composed of welding power source, gas supply system, wire feeding mechanism and welding torch.
(4) Inert gas shielded welding equipment Manual inert gas shielded welding equipment includes welding torch, welding power supply and control device, gas supply and water supply system.
(5) Plasma arc welding equipment Plasma arc welding equipment mainly includes welding power source, control system, welding torch, pneumatic system and waterway system.
Welding equipment system structure characteristics
Mechanical device
The spot welder system consists of three parts: mechanical device, power supply device and control device. In order to meet the welding process requirements, the welding mechanism (welding tongs) adopts a two-stroke fast pneumatic transmission mechanism. By changing the stroke control handle to change the opening degree of the welding tongs, it can be divided into large opening and small opening to meet the welding operation requirements. The normal state is that the welding clamp is short-stroke open. When the control button is switched to the "energized" position, the handle switch is used to clamp the pressure, and the current is restored to the short stroke after completing a welding cycle under the control of the control system. Open state.
2. Power supply unit
The main power circuit is composed of a resistance welding transformer, a thyristor unit, a main power switch, a welding circuit and the like. At present, the welding equipment we use is a single-phase power frequency AC resistance welder with a power of 200kVA and a secondary output voltage of 20V. Due to the collinear production of various models, the welding tongs are to be welded with high-strength steel and low-carbon steel sheets. The welding tongs must transmit large mechanical force and welding current. Therefore, the strength, rigidity and heat of the welding tongs must meet certain requirements. It also has good electrical and thermal conductivity, and requires the welding tongs to be cooled by water. Therefore, the welding tongs can be used to withstand the new welding tongs with a pressure of 400 kg.
3. Control device
The control device mainly provides signal control resistance welder action to turn on and off the welding current, control the welding current value, and perform fault monitoring and processing.
Welding process in the development of the industry
There are more than 40 kinds of metal welding methods, which are mainly divided into three categories: welding, pressure welding and brazing. Fusion welding is a method in which the workpiece interface is heated to a molten state during welding and the welding is completed without pressure. During fusion welding, the heat source rapidly heats and melts the interface of the two workpieces to be welded to form a molten pool. The molten pool moves forward with the heat source, and after cooling, forms a continuous weld to join the two workpieces into one body. During the fusion welding process, if the atmosphere is in direct contact with the high temperature molten pool, oxygen in the atmosphere oxidizes the metal and various alloying elements. Nitrogen, water vapor, etc. in the atmosphere enter the molten pool, and defects such as pores, slag inclusions, cracks, etc. are formed in the weld during subsequent cooling, which deteriorates the quality and performance of the weld.
In order to improve the quality of welding, various protection methods have been developed. For example, gas-shielded arc welding is to insulate the atmosphere with gas such as argon or carbon dioxide to protect the arc and the molten pool rate during welding. For example, when the steel is welded, the ferrotitanium powder with high affinity for oxygen is added to the electrode coating for deoxidation. It can protect the beneficial elements of the electrode, such as manganese and silicon, from oxidation and enter the molten pool, and obtain high-quality welds after cooling.
Pressure welding is to achieve atomic bonding in the solid state under pressure conditions, also known as solid state welding. The commonly used pressure welding process is resistance butt welding. When the current passes through the connection end of the two workpieces, the temperature rises due to the large resistance, and when heated to the plastic state, the connection is integrated under the axial pressure.
A common feature of various pressure bonding methods is the application of pressure during the welding process without the addition of filler material. Most pressure welding methods, such as diffusion welding, high-frequency welding, cold-welding, etc., do not have a melting process, so there is no problem of burning of beneficial alloying elements like welding and intrusion of harmful elements into the weld, thereby simplifying the welding process. Improved safety and hygienic conditions for welding. At the same time, since the heating temperature is lower than the fusion welding and the heating time is short, the heat affected zone is small. Many materials that are difficult to weld by fusion welding can often be welded to a high quality joint of the same strength as the base material.
Brazing is to use a metal material with a lower melting point than the workpiece as a brazing material to heat the workpiece and the brazing material to a temperature higher than the melting point of the brazing material and lower than the melting point of the workpiece. The workpiece is wetted by the liquid brazing material, filling the interface gap and realizing with the workpiece. The method of mutual diffusion between atoms to achieve welding.
The seam formed by welding when joining two connected bodies is called a weld bead. Both sides of the weld are subjected to welding heat during welding, and changes in structure and properties occur. This area is called the heat affected zone. Due to different welding materials and welding currents of the workpiece during welding, overheating, embrittlement, hardening or softening may occur in the weld and heat affected zone after welding, and the weldment performance may be degraded and the weldability may be deteriorated. This requires adjustment of the welding conditions, preheating at the weldment interface before welding, welding heat preservation and post-weld heat treatment can improve the welding quality of the weldment.
In addition, the welding is a local rapid heating and cooling process. The welding zone cannot be freely expanded and contracted due to the restraint of the surrounding workpiece body, and the welding stress and deformation are generated in the weldment after cooling. Important products need to eliminate welding stress after welding and correct welding deformation.
Modern welding techniques have been able to weld welds with no internal or external defects and mechanical properties equal to or even higher than the welded joints. The mutual position of the welded body in space is called the welded joint, and the strength of the joint is affected by the quality of the weld, and also related to its geometry, size, stress and working conditions. The basic forms of the joints are butt joints, lap joints, T-joints (orthogonal joints) and corner joints.
The cross-sectional shape of the butt joint weld is determined by the thickness of the welded body before welding and the groove form of the two joints. When welding a thick steel plate, grooves of various shapes are opened at the joint edges for penetration to facilitate feeding of the welding rod or the welding wire. The groove form has a single-sided welded groove and a double-sided welded groove. When selecting the groove form, in addition to ensuring the penetration, it is also necessary to consider the convenience of welding, the small amount of filler metal, the small welding deformation and the low processing cost of the groove. When two steel plates with different thicknesses are butted together, in order to avoid severe stress concentration caused by sharp changes in the cross section, the thicker plate edges are gradually thinned to be equal to the thickness of the two joint edges. The static strength and fatigue strength of the butt joint are higher than other joints. Welding of butt joints is often preferred over joints that operate under alternating, impact, or low temperature, high pressure vessels. The pre-weld preparation of the lap joint is simple, the assembly is convenient, the welding deformation and the residual stress are small, so it is often used in the installation of joints on the construction site and unimportant structures. In general, lap joints are not suitable for operation under alternating loads, corrosive media, high temperatures or low temperatures.
The use of T-joints and corner joints is usually due to structural requirements. The work characteristics of the fillet welds that are not welded on the T-joint are similar to the fillet welds of the lap joint. When the weld is perpendicular to the direction of the external force, it becomes a front fillet weld. At this time, the shape of the weld surface will cause different degrees of stress concentration; the weld of the fillet weld is similar to that of the butt joint.
The angle joints have low load carrying capacity and are generally not used alone. They are only improved when they are welded or have fillet welds inside and outside. They are mostly used at the corners of closed structures.
Welded products are lighter in weight than rivets, castings and forgings, saving weight and saving energy for transportation. The welding has good sealing properties and is suitable for manufacturing various types of containers. The development of joint processing technology, welding, combination of forging and casting, can be made into a large, economical and reasonable cast-welded structure and forged welded structure, with high economic benefits. The welding process can effectively utilize the materials, and the welded structure can use different performance materials in different parts, giving full play to the advantages of various materials to achieve economic and high quality. Welding has become an indispensable and increasingly important processing method in modern industry.
In modern metal processing, welding is developing later than casting and forging, but the development speed is very fast. The weight of the welded structure accounts for about 45% of the steel output, and the proportion of welded structures of aluminum and aluminum alloys is also increasing.
In the future welding process, on the one hand, new welding methods, welding equipment and welding materials should be developed to further improve welding quality and safety reliability, such as improving existing arc, plasma arc, electron beam, laser and other welding energy; using electronic technology And control technology to improve the process performance of the arc and develop a reliable and lightweight arc tracking method.
On the other hand, it is necessary to improve the mechanization and automation level of welding, such as the program control and digital control of the welding machine; the special welding machine for the automation of all processes from preparation, welding to quality control; and the promotion and expansion of CNC welding on the automatic welding production line. Robots and welding robots can improve the level of welding production and improve the sanitary and safety conditions of welding.
(Plastic) Welding A method in which two or more surfaces of a thermoplastic article are fused together by heating and pressing or other means.
The automation adopts the technical measures of automatic control, automatic adjustment, detection and processing of machinery and equipment, and automatic operation according to specified procedures or instructions. Its purpose is to increase production, improve quality, reduce costs and labor intensity, and ensure production safety. The degree of automation has become one of the important indicators to measure the level of science and technology and economic development in modern countries.
Modern automation technology relies mainly on computer control technology. Welding production automation is the development direction of welding structure production technology. Modern welding automation technology will develop intelligent welding equipment based on high-performance microcomputer-controlled wave welding power supply. Based on the existing welding robot, the flexible welding station and welding production line will be developed, and finally the welding computer integrated manufacturing system CIMS will be realized.
Development of application of microcomputer automation control technology in welding equipment, such as CNC welding power supply, intelligent welding machine, automatic special welding machine and flexible welding robot workstation. The role of the microcomputer control system in various automatic welding and cutting equipment is not only to control various welding parameters, but also to automatically coordinate the actions of the various components of the complete welding equipment to achieve unmanned operation, that is, to achieve numerical control, automation and automation of welding production. Intelligent. The microcomputer-controlled welding power supply has become the basis of the automation-specific welding machine and the intelligent welding equipment. Such as microcomputer controlled thyristor arc welding power source, transistor arc welding power source, inverter arc welding power source, multi-function arc welding power source, pulse arc welding power source, etc. Microcomputer controlled IGBT inverter welding power supply is an ideal device for intelligent control
Most of the special-purpose welding machines of CNC type are automatic TIG welding machines, such as automatic tube/tube TIG welding machine, automatic tube/board TIG welding machine, automatic TIG welding machine and so on. In the welding production, it is often necessary to design and manufacture automated welding process equipment according to the characteristics of the weldment, such as welding machine tools, welding centers, welding production lines and other self-made complete sets of welding equipment, most of which can be used for general welding power supply, automatic welding head, wire feeding. Equipment, welding vehicles and other equipment combinations, and a unified computer control system to coordinate them into a whole.
Advances in welding technology will bring huge business opportunities to the welding industry
China's 2006-2020 Steel Science and Technology Development Guide clearly states that it will gradually produce high-strength, high-toughness steel with a yield strength of 400-800 MPa, tensile strength of 600-1400 MPa, and so-called 21st century super steel with an increase of 1 to 4 times the strength. . With the popularization and application of high-strength steel and ultra-high-strength steel, it will impact the traditional welding design concept. The continuous development and evolution of steel will definitely put forward new and higher requirements for steel structure welding technology.
Therefore, new steel types will emerge in an endless stream. All kinds of high-strength building structural steel, ship plate steel, pressure vessel steel, pipeline steel, bridge steel, heat-resistant steel and low-temperature steel will further sublimate along the development path of the Bird's Nest Q460E-Z35 steel, which will be refined by molten steel. Advanced technologies such as controlled rolling and controlled cooling (TMCP) will develop in the direction of low carbon, microalloying, pure and fine grain, and improve the strength and toughness of steel. This will be the basic technical route for the development of China's steel industry.
GB50661 "Steel Structure Welding Code" conforms to the development track of China's construction steel structure technology, and clarifies the types and applications of high-strength steel, so that the steel structure steel will be oriented in a more advanced direction, which will certainly promote the transformation of welded steel structure.
High-strength steel generally refers to a steel produced with a yield strength greater than 400 MPa and a yield ratio greater than 0.85, which is produced in consideration of weldability. The embrittlement of the heat-affected zone of high-strength steel microalloy controlled rolling and controlled cold steel is an important welding problem. The higher the heat input, the more serious the embrittlement tendency. The embrittlement problem of HAZ mainly includes embrittlement of coarse-grained zone (CGHAZ), embrittlement of critical heat-affected zone (ICHAZ), critical coarse-grained heat affected zone (IRCGHAZ) during multi-layer welding, and supercritical coarse-grained heat affected zone (SRCGHAZ) embrittlement and subcritical coarse-grained heat affected zone (SCGHAZ) embrittlement. Among them, embrittlement of CGHAZ, IRCGHAZ, and SCGHAZ is the most attractive embrittlement zone for microalloyed steel welding.
Due to the high-performance characteristics of high-strength steel slabs, there are high requirements for welding equipment, welding materials and cutting and welding processes, especially for the first pass rate of cutting and welding, otherwise the quality of the weld is difficult to guarantee.
There is every reason to say that the steel structure adopts high-strength steel on a large scale, which will promote the technological progress of the welding industry and create a huge leap, bringing huge business opportunities.
As we all know, a revolution will bring great changes. Various factors will lead to strong alliances of good assets and competition. Success and failure will be combined, opportunities and risks will coexist. In the face of the upcoming revolution, it takes courage to fight. And courage; strategizing, winning a thousand miles requires wisdom and resilience; catching up with the world's advanced level requires more effort and hard work. Empty talk about misunderstanding, hard work, and hope for peers.
Working principle of Panasonic argon arc welding machine
1. What is argon arc welding? The Panasonic argon arc welding machine is a tungsten inert gas shielded arc welding. It refers to a welding method using industrial tungsten or activated tungsten as an infusible electrode and inert gas (argon) for protection, referred to as TIG.
Second, the arcing mode of the Panasonic welding machine The arcing of the argon arc welding adopts the arcing mode of high-voltage breakdown. First, the high-frequency high-voltage is applied between the electrode needle (tungsten needle) and the workpiece, and the argon gas is broken to make it conductive. Supply continuous current to ensure arc stability.
Third, the general requirements of argon arc welding on the gas control requirements: the gas is required to come first and then go, argon gas is easier to be penetrated by the inert gas, first between the workpiece and the electrode needle is filled with argon, which is conducive to arcing; welding After the completion, keep the air supply, help prevent the workpiece from cooling quickly and prevent oxidation, and ensure a good welding effect.
Current hand switch control requirements: When the hand switch is pressed, the current is delayed compared to the air, the hand switch is disconnected (after the welding is finished), and the air supply current is delayed first according to the requirements.
High-pressure generation and control requirements: The argon-arc welding machine adopts the high-pressure arc-starting method, which requires high pressure when starting the arc, and the high voltage disappears after the arcing.
Interference protection requirements: argon arc welding with high frequency in the arcing high voltage, which causes serious interference to the whole circuit, requiring the circuit to have good anti-interference ability.
International welding equipment giant accelerates the pace of opening up the Chinese market
At the just-concluded 13th Beijing Essen International Welding and Cutting Exhibition, many international welding equipment giants have come to the scene. While demonstrating the latest welding equipment, processes and technologies, the Chinese market that has seized rapid economic growth has become these. One of the strategic considerations of the giants.
It is understood that the welding equipment known as "industrial sewing machine" is an important process equipment of modern industry. It is widely used in the efficient connection of metals and alloys, directly affecting the quality, reliability and life of the products as well as production cost, efficiency and market competitiveness. Driven by the sustained rapid growth of China's economy and the acceleration of industrialization, urbanization, and modernization, a number of industries, such as railways, shipbuilding, oil pipelines, construction, and automobiles, which are related to the national economy and the people's livelihood, have strong demand for steel, creating huge business opportunities for the welding equipment market.
According to experts from the China Welding Association, according to the calculation of 25 welding machines per 10,000 tons of steel, China's steel output in 2007 reached 490 million tons, requiring a total of about 1.25 million welding machines. However, limited by domestic production technology and technology, medium and high-end automatic and semi-automatic arc welding machines, resistance welding machines, special welding machines and special complete sets of equipment, which account for half of the total domestic market and worth US$1 billion, still rely on imports.
Faced with such a huge business opportunity in the Chinese market, international welding equipment giants have rushed to the market and strive to expand the market share of high-end welding equipment. Finnish Kemppi Group CEO Angxi. Rantasalo said that the development of China's welding equipment market is an important part of the company's development strategy, and will provide China with more efficient, automated, intelligent, energy-saving and environmentally friendly welding equipment through the “new welding experienceâ€.
How to choose a welding robot system
Many bosses want to automate their production lines because of market conditions. There are not many concepts and experiences for the application of automation equipment. They often make decisions based on the price of the manufacturer when purchasing equipment, and give the advantages that should have been mastered. Amateur opponents. From the perspective of choosing a welding robot welding system to explain how to make the right decision in this regard.
The welding robot system, one set can complete more than 30 products in one day. If the profit of a product is 10 yuan, then the profit for one year (360 days) will be 108,000 yuan. In this case, if the inefficient system is 100/00 yuan cheaper than the more efficient system, it is not worth buying.
The efficiency of the welding robot system can be determined from many aspects, such as welding cycle (cycle), mean time between failures, average time to failure recovery, zero recovery time, teaching time, programming time, etc. These parameters are explained and analyzed.
The length of the welding cycle (cycle) cannot be calculated from the average speed of the robot on the catalog. Because the robot must run according to the programmed trajectory throughout the welding process, the trajectory consists of many points. Because the robot's motion is controlled by a closed-loop control system, many other robotic technical parameters have a large impact on the welding tempo, such as average positioning time, rise and correction time, rate, acceleration, and so on. These parameters usually do not appear in the directory.
In addition to efficiency, the life of the equipment is also part of the cost. The longer the life of the equipment, the lower the production cost.
Another point worth considering is whether the function of the device is diversified, because the market is changing rapidly, and if the device function can be easily changed, it is more advantageous. Such as the conversion from CO2 gas shielded welding to argon arc welding, welding of stainless steel from welding stainless steel, transfer from the welding robot to carry, bending or polishing the robot.
The difference, advantages and disadvantages between domestic welding robots and imported robots
At present, the robot applications in the domestic market are mainly divided into Japanese, European and domestic. Japanese robots mainly use Yaskawa MOTOMAN, OTC, Panasonic, FANUC and other robots. Europe and the United States are Germany's KUKA, CLOOS, Sweden's ABB and Austria's IGM. The domestic robots are mainly Shenyang Xinsong robot and Guangzhou CNC. The difference and characteristics of welding robots in Europe and America. The same point: mainly used for spot welding and arc welding, can be applied to automated production lines, welding production lines. Used in many fields, including welding, handling, spraying, etc.
difference:
1, Japanese welding robots are more focused on arc welding, such as OTC, Panasonic, motoman, etc.; Europe and the United States are more focused on spot welding, such as KUKA.
2. European and American robots can be widely used in the spray industry, such as ABB.
3. Japanese welding robots are about 30% cheaper than those in Europe and America, and can be applied to most fields, which is more suitable for the domestic market.
4. Regardless of the algorithm, European and American robots have a large advantage (less than 1 ton) in terms of accuracy and load compared to Japanese.
At present, although there are already series of welding robots with independent intellectual property rights in China, they cannot be mass-produced and form scale. There are several main reasons:
There is no advantage in domestic robot prices. In the past 10 years, the price of imported robots has been greatly reduced, from $70,000 to $30,000 to $30,000, making it difficult for ordinary industrial robots made in China to compete with them. In particular, in the early stage of developing robots in China, there was no simultaneous development of the corresponding parts and components industry, such as servo motors, reducers, etc., which required the import, which made it difficult to reduce the price, so the cost of robot production could not be reduced. The level of welding equipment in China still exists very much abroad. The big gap, this also indirectly affects the development of domestic robots. For the car's largest user, the car body-in-white manufacturer, almost all of the equipment has been imported from abroad, and domestic robots can hardly find a stage for performance.
We should admit that domestic robots still have a certain gap with foreign companies in terms of control level and reliability. Foreign industrial robots are very mature industrial products. After more than 30 years of development, they are constantly improving and improving in actual production, while China is in a single-piece and small-batch production state.
Domestic robot manufacturers are in their early childhood and need government policy and funding support. The welding robot is a mechatronics high-tech product. It is not enough to rely solely on the company's own capabilities. It requires the government to give certain policies and financial support to robot manufacturers and enterprises using domestic robot systems to accelerate the development of domestic robots.
However, in welding parts with relatively simple processes, domestic welding robots have a strong competitive advantage. Moreover, the structure is simple, the skill requirements for employees are relatively low, and the repair costs are relatively low.
In the imported welding robot, complex workpiece welding can be realized, and there are strong technical requirements for operators and repairmen. The accessories are relatively expensive, and the supply of parts is difficult to be timely.
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Sliver Tungsten Electrode
Sliver tungsten Electrode is alloy of tungsten and sliver ,also called sliver tungsten bar or sliver tungsten rod .
Sliver tungsten electrode physical properties .
Density :11.75-16.10g/cm ², it depend on the content of tungsten and sliver
Composition W30-80 5,Ag 20-70%
Silver tungsten electrode is feature with high arc corrosion ,high hardness ,nice electtial conductivity and high fusion welding resistance etc.
Application of sliver tungsten electrode
Sliver tungsten electrode commonly used as switches, it performs well in AC welding
Used in high temperature resistance industry
Applied for sport equipment
Silver tungsten electrode
Because of the mutal solubility of tungsten sliver is too low ,sliver tungsten electrode only can be manufactured by Powder Metallurgy and pressing method .
Silver Tungsten Alloy Switch Contacts
Tungsten Alloys,Silver Tungsten Alloy Switch Contacts,Agw Welding Electrode,Crzrcu Welding Electrode
Shenyang Top New Material Co., Ltd. , http://www.topcobalt.com