Through technology sharing, let you know the welding method of pressure welding.
Release time:
2022-07-23
【Summary Description】 This is a kind of welding method with resistance heat as energy source, including electroslag welding with slag resistance heat as energy source and resistance welding with solid resistance heat as energy source. Since electroslag welding has more unique characteristics, it is introduced later. Here mainly introduces several kinds of solid resistance heat for energy resistance welding, mainly spot welding, seam welding, projection welding and butt welding. Resistance welding is generally a welding method that makes the workpiece under a certain electrode pressure and uses the resistance heat generated when the current passes through the workpiece to melt the contact surface between the two workpieces and realize the connection. Larger currents are usually used. In order to prevent arcing on the contact surfaces and in order to forge the weld metal, pressure is always applied during the welding process. When performing this type of resistance welding, the surface of the workpiece being welded is of paramount importance for obtaining a stable welding quality. Therefore, the contact surface between the electrode and the workpiece and the workpiece must be cleaned before welding. Advantages: 1) When the nugget is formed, it is always surrounded by a plastic ring, the molten metal is isolated from the air, and the metallurgical process is simple. 2) The heating time is short, the heat is concentrated, so the heat affected zone is small, and the deformation and stress are also small. Usually, it is not necessary to arrange the correction and heat treatment process after welding. 3) No filler metals such as welding wires and welding rods, as well as Welding materials such as oxygen, acetylene and argon, are required, and the welding cost is low. 4) Simple operation, easy to realize mechanization and automation, and improve working conditions. 5) high productivity, and no noise and harmful gases, in mass production, can be made with other manufacturing processes to the assembly line. However, flash butt welding requires isolation due to spark spatter. Disadvantages: 1) At present, there is still a lack of reliable non-destructive testing methods, welding quality can only be checked by destructive testing of process samples and workpieces, as well as by various monitoring technologies. 2) The lap joint of point and seam welding not only increases the weight of the component, but also causes the tensile strength and fatigue strength of the joint to be lower due to the angle formed around the nugget between the two plates. 3) The equipment has high power and high degree of mechanization and automation, which makes the equipment cost high and maintenance difficult, and the commonly used high-power single-phase AC welding machine is not conducive to the normal operation of the power grid. Scope of application: It is widely used in automobiles, aircraft, instruments, home appliances, steel bars for construction, and other industries. It is widely used in a wide range of materials, but the resistance welding of easily oxidized metals is slightly worse. It is mainly used for welding thin plate components with thickness less than 3mm. All kinds of steel, aluminum, magnesium and other non-ferrous metals and their alloys, stainless steel can be welded. 2 friction welding Friction welding is a solid-phase welding that uses mechanical energy as an energy source. It uses the heat generated by the mechanical friction between the two surfaces to achieve the metal connection. The heat of friction welding is concentrated at the joint surface, so the heat affected zone is narrow. Pressure must be applied between the two surfaces. In most cases, the pressure is increased when the heating is terminated, so that the hot metal is combined by upsetting, and the joint surface is generally not melted. Friction welding productivity is high, in principle, almost all hot forging metal can be friction welding. Friction welding can also be used for welding dissimilar metals. To be applied to the cross section of the circular maximum diameter of 100mm workpiece. A solid-phase pressure welding method that uses the heat generated by the friction of the welding contact end faces to make the end faces reach a thermoplastic state, and then quickly exerts a forging force to realize welding, Friction welding has the following advantages: (1) The welding quality is stable, the welding size accuracy is high, and the joint rejection rate is lower than that of resistance butt welding and flash butt welding. (2) Welding productivity is high, 5 to 6 times higher than flash butt welding. (3) It is suitable for welding dissimilar metals, such as carbon steel, low alloy steel and stainless steel, high-speed steel, copper-stainless steel, copper-aluminum, aluminum-steel, steel-zirconium, etc. (4) The processing cost is low, the power is saved, and the welding parts do not need special cleaning. (5) easy to realize mechanization and automation, simple operation, welding work site without sparks, arc and harmful gases. Disadvantages: it is difficult to weld non-circular section by rotating the workpiece. Disc-shaped workpieces and thin-walled pipe fittings are also difficult to weld because they are not easy to clamp. Limited by the power of the welding machine spindle motor, the maximum section that can be welded by friction welding is 20000 mm2. Friction welding machine one-time investment cost is large, suitable for mass production. Application: dissimilar metal and dissimilar steel products, such as copper-aluminum transition joints in the power industry, high-speed steel-structural steel tools for metal cutting, etc.; structural steel products, such as power station boiler serpentine tubes, valves, tractor bearings, etc. 3 diffusion welding Diffusion welding is generally a solid-phase welding method using indirect heat energy as energy. It is usually carried out under vacuum or a protective atmosphere. During welding, the surfaces of the two welded workpieces are contacted and held for a certain period of time under high temperature and high pressure to reach the distance between atoms, which are combined by simple diffusion of atoms. Before welding, it is not only necessary to clean the oxide and other impurities on the surface of the workpiece, but also the surface roughness must be lower than a certain value to ensure the welding quality. Diffusion welding is under the protection of vacuum or protective atmosphere, under certain temperature (lower than the melting point of the base metal) and pressure conditions, the smooth and smooth surfaces to be welded in contact with each other are in close contact after microscopic plastic flow, and the atoms diffuse each other. After a long period of time, the original interface disappears, and the welding method of complete metallurgical combination is achieved. Diffusion welding has the following advantages: (1) can be almost no damage to the performance of the material to be welded, to achieve all kinds of the same material and different materials between the welding, can be used to manufacture double or multi-layer composite materials. (2) It can weld workpieces with complex structures and large differences in thickness. (3) The joint composition and organization are uniform, which reduces the tendency of stress corrosion. (4) The welding deformation is small and the joint precision is high, which can be used as the final assembly and connection method of the parts. (5) It can be carried out at the same time as other processing techniques (such as vacuum heat treatment, etc.), and the welding of multiple joints can be completed at the same time, thereby improving productivity. Disadvantages: Diffusion welding has high requirements for surface processing and cleaning of weldments, long welding time, low productivity, high cost, and large equipment investment. Application: welding between dissimilar metals with large melting point difference or metallurgical incompatibility, welding of metal and ceramic and welding of titanium, nickel and aluminum alloy structural parts. Not only used in atomic energy, aerospace and electronics industry and other cutting-edge technology, and has been extended to the general machinery manufacturing industry sector.
This is a kind of welding method with resistance heat as energy source, including electroslag welding with slag resistance heat as energy source and resistance welding with solid resistance heat as energy source. Since electroslag welding has more unique characteristics, it is introduced later. Here mainly introduces several kinds of solid resistance heat for energy resistance welding, mainly spot welding, seam welding, projection welding and butt welding. Resistance welding is generally a welding method that makes the workpiece under a certain electrode pressure and uses the resistance heat generated when the current passes through the workpiece to melt the contact surface between the two workpieces and realize the connection. Larger currents are usually used. In order to prevent arcing on the contact surfaces and in order to forge the weld metal, pressure is always applied during the welding process. When performing this type of resistance welding, the surface of the workpiece being welded is of paramount importance for obtaining a stable welding quality. Therefore, the contact surface between the electrode and the workpiece and the workpiece must be cleaned before welding.
Advantages:1) When the nugget is formed, it is always surrounded by a plastic ring, the molten metal is isolated from the air, and the metallurgical process is simple. 2) The heating time is short, the heat is concentrated, so the heat affected zone is small, and the deformation and stress are also small. Usually, it is not necessary to arrange the correction and heat treatment process after welding. 3) No filler metals such as welding wires and welding rods, as well as Welding materials such as oxygen, acetylene and argon, are required, and the welding cost is low. 4) Simple operation, easy to realize mechanization and automation, and improve working conditions. 5) high productivity, and no noise and harmful gases, in mass production, can be made with other manufacturing processes to the assembly line. However, flash butt welding requires isolation due to spark spatter.
Disadvantages:1) At present, there is still a lack of reliable non-destructive testing methods, welding quality can only be checked by destructive testing of process samples and workpieces, as well as by various monitoring technologies. 2) The lap joint of point and seam welding not only increases the weight of the component, but also causes the tensile strength and fatigue strength of the joint to be lower due to the angle formed around the nugget between the two plates. 3) The equipment has high power and high degree of mechanization and automation, which makes the equipment cost high and maintenance difficult, and the commonly used high-power single-phase AC welding machine is not conducive to the normal operation of the power grid.
Scope of application:It is widely used in automobiles, airplanes, instruments, home appliances, steel bars for construction, and other industries. It is widely applicable to a wide range of materials, but the resistance welding of easily oxidized metals is slightly worse. It is mainly used for welding thin plate components with thickness less than 3mm. All kinds of steel, aluminum, magnesium and other non-ferrous metals and their alloys, stainless steel can be welded.
Friction welding is a solid-phase welding that uses mechanical energy as an energy source. It uses the heat generated by the mechanical friction between the two surfaces to achieve the metal connection. The heat of friction welding is concentrated at the joint surface, so the heat affected zone is narrow. Pressure must be applied between the two surfaces. In most cases, the pressure is increased when the heating is terminated, so that the hot metal is combined by upsetting, and the joint surface is generally not melted. Friction welding productivity is high, in principle, almost all can be hot forging metal can be friction welding. Friction welding can also be used for welding dissimilar metals. To be applied to the cross section of the circular maximum diameter of 100mm workpiece.
A solid-phase pressure welding method that uses the heat generated by the friction of the welding contact end faces to make the end faces reach a thermoplastic state, and then quickly exerts a forging force to realize welding,
Friction welding has the following advantages:
(1) The welding quality is stable, the welding size accuracy is high, and the joint rejection rate is lower than that of resistance butt welding and flash butt welding.
(2) Welding productivity is high, 5 to 6 times higher than flash butt welding.
(3) It is suitable for welding dissimilar metals, such as carbon steel, low alloy steel and stainless steel, high-speed steel, copper-stainless steel, copper-aluminum, aluminum-steel, steel-zirconium, etc.
(4) The processing cost is low, the power is saved, and the welding parts do not need special cleaning.
(5) easy to realize mechanization and automation, simple operation, welding work site without sparks, arc and harmful gases.
Disadvantages:It is difficult to weld non-circular sections by workpiece rotation. Disc-shaped workpieces and thin-walled pipe fittings are also difficult to weld because they are not easy to clamp. Limited by the power of the welding machine spindle motor, the maximum section that can be welded by friction welding is 20000 mm2. Friction welding machine one-time investment cost is large, suitable for mass production.
Application:Dissimilar metal and dissimilar steel products, such as copper-aluminum transition joints in the power industry, high-speed steel-structural steel tools for metal cutting, etc.; structural steel products, such as power station boiler serpentine tubes, valves, tractor bearings, etc.
Diffusion welding is generally a solid-phase welding method using indirect heat energy as energy. It is usually carried out under vacuum or a protective atmosphere. During welding, the surfaces of the two welded workpieces are contacted and held for a certain period of time under high temperature and high pressure to reach the distance between atoms, which are combined by simple diffusion of atoms. Before welding, it is not only necessary to clean the oxide and other impurities on the surface of the workpiece, but also the surface roughness must be lower than a certain value to ensure the welding quality.
Diffusion welding is under the protection of vacuum or protective atmosphere, under certain temperature (lower than the melting point of the base metal) and pressure conditions, the smooth and smooth surfaces to be welded in contact with each other are in close contact after microscopic plastic flow, and the atoms diffuse each other. After a long period of time, the original interface disappears, and the welding method of complete metallurgical combination is achieved.
Diffusion welding has the following advantages:
(1) can be almost no damage to the performance of the material to be welded, to achieve all kinds of the same material and different materials between the welding, can be used to manufacture double or multi-layer composite materials.
(2) It can weld workpieces with complex structures and large differences in thickness.
(3) The joint composition and organization are uniform, which reduces the tendency of stress corrosion.
(4) The welding deformation is small and the joint precision is high, which can be used as the final assembly and connection method of the parts.
(5) It can be carried out at the same time as other processing techniques (such as vacuum heat treatment, etc.), and the welding of multiple joints can be completed at the same time, thereby improving productivity.
Deficiencies:Diffusion welding has high requirements for surface processing and cleaning of weldments, long welding time, low productivity, high cost, and large equipment investment.
Application:Welding between dissimilar metals with large melting point difference or metallurgical incompatibility, welding of metals and ceramics, and welding of titanium, nickel, and aluminum alloy structural parts. Not only used in atomic energy, aerospace and electronics industry and other cutting-edge technology, and has been extended to the general machinery manufacturing industry sector.
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