Forming process of stamping elbow

Forming process of stamping elbow  

Stamping elbow forming: stamping elbow is early used in the mass production of seamless elbow forming technology, in the common standard elbow production has been replaced by hot push method or other forming technology, but in some standard elbow due to the production of less, wall thickness is too thick or too thin.  Products with special requirements are still in use.  The elbow stamping is formed by using the tube blank which is equal to the outer diameter of the elbow and the press is used to limit the forming directly in the mold.  Before stamping, the tube blank is placed on the die, and the inner core and the end die are loaded into the tube blank. The downward movement of the upper die is restricted, and the elbow is formed by the restriction of the outer die and the support of the inner die.  

Compared with 0 thermal push process, the appearance quality of stamping is inferior to that of 0 thermal push process.  When the stamping elbow is formed, the outer arc is in a stretch state, and there is no excess metal compensation in other parts, so the wall thickness at the outer arc is reduced about 10%.  However, due to the characteristics of single production and low cost, stamping elbow technology is mostly used for the production of small batch, thick wall elbow.  Stamping elbow is divided into cold stamping and hot stamping, usually according to the nature of the data and equipment to choose cold stamping or hot stamping.  Cold kneading elbow forming process is the use of commonly used elbow forming machine, the tube blank into the outer mold, up and down the mold, under the push rod, the tube blank along the inner mold and the outer mold reserved gap movement and complete the forming process.  Choose the inside mold cold kneading process made of elbow beautiful appearance, uniform wall thickness, small size error, so for stainless steel elbow, especially thin-walled stainless steel elbow forming more use this process.  The precision of the inner mold used in this process is high;  The requirement of wall thickness error is also very strict.  

Middle plate welding: use the middle plate to make half of the elbow section with a press, and then weld the two sections together.  This process is generally used to make elbow more than DN700.