Process flow of 45° Elebow C*C
Elbows are pipe fittings used for pipe bending. Among all pipe fittings used in the piping system, the proportion is relatively large, about 80%. Usually, elbows of different materials or wall thicknesses are formed by different forming processes. At present, the commonly used seamless elbow forming processes include hot push, stamping, extrusion, etc. The hot push elbow forming process uses a dedicated elbow pusher, core mold and heating device to make the blank on the mold press the pusher It moves forward under the push of the elbow, heating, expanding, and bending during the movement. The deformation characteristic of the hot push elbow is to determine the diameter of the tube blank according to the law of constant volume before and after the plastic deformation of the metal material. The diameter of the tube blank is smaller than the diameter of the elbow, and the core model is used to control the deformation process of the blank, so that the compressed metal flow at the inner arc is compensated to other parts of the expansion and thinning, so as to obtain an elbow with uniform wall thickness.
The hot push elbow has beautiful forming process, uniform wall thickness and continuous operation. It is suitable for mass production. It has become the main forming method for alloy steel elbows. It is also suitable for the forming of certain specifications of stainless steel elbows. The heating method of the forming process is intermediate frequency. Or high-frequency induction heating, flame heating and reflective surface heating. The heating method depends on the requirements and energy conditions of the formed product.
Stamping is a long-term forming process used in the mass production of seamless elbows. It has been replaced by hot pressing or other forming processes. It is used to produce elbows of common specifications. However, in some specifications of elbows, Its output is small, and the wall is too thick or too thin.
Before punching, the tube blank is placed on the lower mold, the inner core and the end mold are loaded into the tube blank, and the elbow is formed by the constraint of the outer mold and the support of the inner mold. Compared with the hot forming process, the appearance quality of stamping forming is not as good as the hot pressing forming process, and the outer arc of the stamping elbow is in a stretched state during the forming process.
Stamping elbows are divided into cold stamping and hot stamping. Cold stamping or hot stamping is usually selected according to material properties and equipment capacity.
The forming process of 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 moves along the gap between the inner mold and the outer mold. , Complete the forming process.The inner and outer die cold extrusion forming elbow has the advantages of beautiful appearance, uniform wall thickness, and small size deviation. It is often used for the forming of elbows, especially the forming of thin-walled elbows. Thickness deviation also puts forward higher requirements.