The Forming Process of Stamped Pipe Elbow

　　Stamped pipe elbows have been replaced by hot extrusion or other forming processes in the production of commonly used specifications of pipe elbows, but they are still used in some specifications of pipe elbows due to limited production quantity, excessive wall thickness, or product requirements. The stamping forming of the pipe elbow adopts a pipe blank equal to the outer diameter of the pipe elbow, and is directly pressed into shape in the mold using a press. Before stamping, the tube blank is placed on the lower mold, and the inner core and end mold are loaded into the tube blank. The upper mold moves downward to start pressing, and the pipe elbow is formed by the constraint of the outer mold and the support of the inner mold. Compared with hot pressing process, the appearance quality of stamping forming is not as good as the former; The outer arc of the stamped pipe 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%.

　　Stamped pipe elbows are suitable for single piece production and low cost characteristics, so the stamping pipe elbow process is mostly used for the manufacturing of small batch, thick wall elbows. Stamped pipe elbows can be divided into two types: cold stamping and hot stamping, which are usually selected based on material properties and equipment capabilities. The forming process of cold extrusion elbows is achieved by using an pipe elbow forming machine, which places the tube blank into the outer mold. After the upper and lower molds are closed, the tube blank moves along the gap reserved by the inner and outer molds under the push of the push rod to complete the forming process.