Stamping elbow is the earliest forming process used in mass production of seamless elbows. It has been replaced by hot push or other forming processes in the production of commonly used elbows. However, in some specifications of elbows, due to the production quantity Less, the wall thickness is too thick or too thin.
The product is still in use when there are special requirements. The stamping and forming of the elbow adopts a tube blank with the same outer diameter as that of the elbow, and is directly pressed into a mold by a press.
Before punching, the tube blank is placed on the lower mold, the inner core and the end mold are loaded into the tube blank, the upper mold moves downward to start pressing, and the elbow is formed by the restraint of the outer mold and the support of the inner mold.
Compared with the hot push process, the appearance quality of stamping forming is not as good as the former; the outer arc of the stamping elbow is in a stretched state during forming, and there is no excess metal in other parts to compensate, so the wall thickness at the outer arc is reduced by about 10% . However, due to the characteristics of being suitable for single-piece production and low cost, the stamping elbow process is mostly used for the manufacture of small batches and thick-walled elbows.
There are two types of stamping elbows: cold stamping and hot stamping. Cold stamping or hot stamping is usually selected according to 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. The gap movement completes the forming process.
The elbow manufactured by the cold extrusion process of 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 precision requirements of the inner and outer molds used in this process are high; the requirements for the wall thickness deviation of the tube blank are also strict.
