The elbow of seamless pipe is the main connection of pressure pipe. At present, the production of seamless elbows includes cold push, hot push, stamping and other methods, while cold push technology still occupies an important position in elbow production. Although cold-pushed elbow has prominent advantages, its deformation law is complex and the process is difficult to control. Therefore, it is necessary to study the cold forming process of elbow and improve the technology of cold-pushed elbow to provide it with technology. Develop elbow production technology. Support.


The cold push process of elbow is simulated and analyzed, and the results of finite element simulation are compared with the actual production results. The reliability of finite element simulation was determined, and 273*8 was determined by optimizing the measurement method of tube blank size. The size of elbow billet was optimized, and the feasibility of using back thrust simulation to obtain the size of tube billet was proved. The optimum parameters of 219*8 and 508*8 cold elbows were obtained by orthogonal test. Measure the cold elbow and analyze the forming results. The parameters such as the uniformity of elbow wall thickness and the ellipticity of the end face were tested. Test elbow parameters to meet the standard index of pipe fittings. With the continuous development and advancement of industrialization, the use of pipelines plays an increasingly important role in various fields and industries. Especially in the electric power and petroleum industry, the demand for pipe fittings and components is increasing, and the demand for pipeline equipment is increasing, which makes the pipeline industry continue to carry out technological innovation. With the continuous progress of industrial production, the development of tube forming technology is particularly important.


The forming of pipe fittings is the processing technology of pipe fittings required by plastic deformation in the production process. In order to meet the various needs of the production of elbows, a large number of experiments and studies have been carried out by skilled workers and many scholars, and technological innovations have been made in the processing technology of elbows, so that the processing technology can be carried out. The elbow is perfect. The aim of simulated elbow forming technology is to improve the production process of elbow.


The hot push forming technology uses induction heating to heat the tube blank and plasticize the material, then uses two-step hydraulic drive to bend and expand the diameter under the action of the mandrel in the tube blank, forming a larger diameter than the tube blank. Elbow shaping method. Hot push forming elbow is suitable for continuous production. It has fast production speed and can produce elbows of different specifications. In the existing elbow forming method, it is a low production cost forming method, so it is widely used in bending. Production head.  However, when carbon steel elbow is formed, the inner horn mandrel has high red hardness requirement, and the heating temperature of elbow should be controlled between 750 and 950 during the forming process.


The elbow produced by hot pressing process has beautiful appearance, good forming quality and relatively uniform wall thickness, which is very suitable for continuous mass production. Therefore, the forming process is usually used when forming alloy steel, stainless steel and carbon steel elbows, such as hot pushing.  When forming elbows by hot push forming, which heating method to use is very important. At present, there are three main heating methods: induction heating, tempering furnace heating and flame heating. In actual production, the appropriate heating method is usually chosen according to product requirements and actual factory conditions.


The so-called pressing forming is a method in which billets with inner cores are directly used to extrude and extrude elbows by using dies. At the beginning of seamless elbow production, stamping method realized large-scale production of elbow and was widely used in elbow production. There are some shortcomings in the stamping forming method, such as poor forming quality of elbow, large deviation of elbow wall thickness, bad appearance of forming elbow, and the required die when large size elbow needs to be formed. The cost is also high. Therefore, in today's elbow production, stamping has gradually been replaced by other forming methods. However, in the production of some special specifications of elbows