how to make steel pipe seamless elbow
Steel pipe seamless elbow Manufacturers commonly used seamless elbow forming process hot push, stamping, extrusion and so on.
Seamless elbows: Elbows are a kind of pipe fittings used for turning pipes. Of all the pipe fittings used in the piping system, the largest share is about 80%. In general, different forming processes are chosen for different materials or wall thickness bends.
A. Hot push forming
The hot push seamless elbow forming process is to use a special elbow push machine, core mold and heating device, so that the blank sleeved on the mold moves forward under the push of the push machine, and is heated, expanded and combined during the movement. The process of bending.
The hot push elbow forming process has the characteristics of beautiful appearance, uniform wall thickness and continuous operation, and is suitable for mass production. Therefore, it has become the main forming method for carbon steel and alloy steel elbows, and is also applied to certain specifications of stainless steel elbows. Is forming.
The heating methods of the forming process include medium frequency or high frequency induction heating (the heating ring can be multiple or single), flame heating and reverberatory furnace heating. The heating method used depends on the requirements of the formed product and the energy situation.
B. Stamping and forming
Seamless elbow stamping forming elbow is the earliest forming process used in mass production of seamless elbows. At present, the hot push method or other forming processes have been replaced in the production of commonly used elbows, but in some specifications In elbows, they are still used when there are special requirements for products due to the small number of production, excessive thickness or thinness. The stamping and forming of the elbow adopts a tube blank with the same outer diameter as that of the elbow, which is directly pressed in the mold by a press.
Stamping elbows are divided into cold stamping and hot stamping. Usually, cold stamping or hot stamping is selected according to the material properties and equipment capabilities. The forming process of the cold extrusion elbow is to use a special elbow forming machine to put the tube blank into the outer mold. After the upper and lower molds are closed, under the push of the push rod, the tube blank follows the reserved The gap movement completes the forming process. Figure 15-8 is a photo of a stainless steel elbow in a manufacturer before and after extrusion.
The elbow manufactured by the cold extrusion process of the inner and outer molds has beautiful appearance, uniform wall thickness and small size deviation. Therefore, this process is often used for the forming of stainless steel elbows, especially thin-walled stainless steel elbows. The internal and external molds used in this process require high precision; the requirements for the wall thickness deviation of the tube blank are also strict.
C. Other forming methods
In addition to the three commonly used forming processes for seamless elbows, seamless elbows are formed by extruding the tube blank to an outer mold, and then passing through the tube blank to shape the forming process. However, this process is relatively complicated, troublesome to operate, and the forming quality is not as good as the foregoing process, so it is rarely used.