Since the birth of electron beam welding technology in the 1950s, its power density, welding heat input is small, parts deformation is small, residual stress after welding is small, weld depth-to-width ratio is large, welding joints are non-oxidized, and weld quality is good. And other characteristics, widely used in aviation, aerospace and atomic energy industries. In the aerospace manufacturing industry, the application of electron beam welding technology has greatly improved the manufacturing level of aircraft engines, making many weight reduction designs and welding of dissimilar materials in the engine a reality, greatly improving the performance and manufacturing level of the engine. Many parts that are difficult to achieve in overall machining provide a way to machine. With the development of modern new engines, electron beam welding has become more and more widely used in this field and has shown great advantages.
Application of Electron Beam Welding in the Manufacturing of Engine Fan Cases
In the manufacturing process of aero engine low-pressure fan casing, in order to reduce the weight of the engine, the new engine fan casing is made of titanium alloy, and the process of electron beam welding of the outer ring of the casing and the stator blade is simplified, and the manufacturing process is simplified. During the welding process of the alloy, the electron beam welding is carried out in a vacuum, completely avoiding the oxidation problem of the titanium alloy in the atmosphere welding, the electron beam welding heat input is small, the part deformation is small, and the numerical control programming can be completed once, the production efficiency High, good welding quality. The use of the welded structure greatly reduces the weight of the fan, and in order to further reduce the weight, the wall thickness of the casing is reduced while ensuring the rigidity and rigidity of the casing. Since the airflow channel can no longer be processed after the casing welding, the electron beam welding of the fan casing first selects the appropriate welding parameters, so that the titanium alloy material is welded to realize the double-sided forming of the single-sided welding, and the welding spatter cannot be generated during the welding. , and the back stack height of the weld can not be too large, otherwise it will affect the movement of the gas in the runner flow; then use the appropriate welding process and welding heat treatment tool to ensure the minimum deformation of the parts after welding; finally, prepare a reasonable and feasible NC program , complete the welding of the parts. The first, second and third stage machines of a machine processed by electron beam welding are in good condition.
Application of Electron Beam Welding in Compressor Manufacturing
Electron beam welding is more widely used in the manufacture of compressor components. The compressor rotor is generally selected from GH4169 material and titanium alloy material. Its main features are high speed, thousands or tens of thousands of revolutions per minute. The drum-type rotor has the bending rigidity of the drum rotor and the bearing of the disc rotor. The ability to large centrifugal loads is therefore widely used, especially on high pressure compressors for modern turbofan engines.
On the non-removable drum-type rotor, cylindrical surface tightness and radial pin connection and welding are usually adopted. The mechanical connection has the advantages of simple structure and reliable operation, but the rotor has many parts, and manufacturing deviation will affect the rotor. Centering and balance, the structure of the joint should be widened and thickened, which will increase the weight of the rotor. With the development of welding technology, more and more welded rotors are used in modern advanced engines. Welding rotors generally use electron beam welding and friction welding.
The welded drum-type rotor does not require connecting parts. The concentricity and runout requirements of the components must be ensured during the welding process, which avoids the quality instability factors that may occur in the processing and assembly, thus effectively reducing the weight of the structure and improving the rotor. Work reliability, but the welding method of the rotor has high requirements on the welding technology. It is necessary to ensure that the weld quality of the part meets the requirements of the acceptance criteria, and the welding quality of the weld should be very stable, and the quality of one weld is super poor. It may cause the entire rotor to be unusable. The electron beam welding of the rotor must ensure high precision, small deformation, no oxidation, high strength, low residual stress and stable quality. This requires large CNC electron beam welding equipment and mature welding technology, and also depends on welding tooling. And reasonable craftsmanship is guaranteed.
In the manufacture of the electron beam welded structural parts of the compressor rotor, the hole defects are easily generated in the weld during the welding process, especially the titanium alloy. Since the number of welding stages of the rotor parts is large, and the production cost of the parts is high, the welding is generally In case you want to ensure a success. Since the post-weld substrate is removed before the flaw detection, once defects (such as air holes) in the weld are difficult to completely eliminate by one repair welding, the rationality of the welding parameters should be verified on the dummy parts before welding, in order to prevent The generation of air holes, the exhaust groove should be processed on the substrate of the welded joint, the cleaning before the joint welding should be very clean, and the joints should be chemically and mechanically cleaned according to the different materials; the penetration welding in the welding process is beneficial to eliminate Pore ​​defects, but the welding spatter should be protected, and the welding heat input is large, and the parts are easy to deform. For non-penetrating welding, the defects generated in the welding must be introduced into the welding substrate as deep as possible, and then The substrate is removed without modifying the soldering process; in order to ensure the quality of the solder joint, the substrate is generally thickened and soldered to the back of the substrate, so that there is no problem of spatter burn and adhesion, and the deformation of the part is easy. control. Since some internal shapes of the parts cannot be processed after welding, the concentricity, welding shrinkage and runout value of the rotor parts after welding are very strict. It is necessary to take measures from the welding process, welding and heat treatment tools to prevent the rotor. The deformation.
In order to further reduce the structural weight of the rotor parts, modern advanced engines have adopted the overall blade disc manufacturing technology, which uses integral machining or linear friction welding to connect the discs and blades according to the ease of processing and economy, greatly reducing the weight of the joints. The connection between the disc and the disc is performed by an electron beam welding process. This technology has been adopted in military and civil aircraft engine compressor rotors in Western countries, and China is accelerating technical research and research work in this area.
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There are many methods of hole processing, the common ones are drilling, reaming, boring, and other processes. The most common is hole processing on lathes, drilling machines, and boring machines.
Reprocessing the existing holes with a boring tool is called boring.For larger holes, inner forming surfaces, inner ring grooves, etc., boring is the only suitable processing method.
Internal Threading Boring Bar,Internal Threading Piercing,Threading Boring Bar,Boring Bar
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