A stainless steel elbow is a pipe fitting that changes the direction of the pipe. According to the angle, there are three common types, such as 45°, 90°, and 180°. The processing methods of stainless steel elbows are generally mechanical processing such as: stamping method, forging method, roller processing method, rolling method, bulging method, stretching method, bending method, and combined processing method;
However, in the current production and processing, there are not many common methods for processing stainless steel elbows.
There are three commonly used forming methods for stainless steel elbows: stretching, stamping, and roller.
Forging method: The end portion or a part of the stainless steel pipe is punched by a swaging machine to reduce the outer diameter. The common type forging machine has a rotary type, a link type, and a roller type.
Stamping method: The end of the tube is expanded to the required size and shape with a tapered core in the stainless steel elbow.
The stamping forming of stainless steel elbows is the earliest forming process for mass production of elbows. At present, it has been replaced by hot push or other forming processes in the production of seamless elbows of common specifications, but in some specifications of elbows It is still used because of the small amount of production, excessive wall thickness or special requirements of the product. The stamping elbow is formed by using a tube blank equal to the outer diameter of the elbow, and is directly press-formed in the mold using a press.
Before the stamping, 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 is moved downward to start pressing, and the punching elbow is formed by the constraint of the outer mold and the support of the inner mold.
Compared with the hot push process, the appearance quality of stamping is not as good as the former; when the punch elbow is in the stretched state when forming, there is no excess metal in other parts to compensate, so the wall thickness at the outer arc is about 10% thinner. . However, due to the characteristics of single-piece production and low cost, the stamping elbow process is mostly used for the manufacture of small batches and thick-walled elbows.
Stamping elbows are divided into 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. After the upper and lower molds are closed, the blank is reserved along the inner and outer molds under the push of the push rod. The gap moves to complete the forming process.
The elbow manufactured by the inner and outer mold cold extrusion process has beautiful appearance, uniform wall thickness and small dimensional deviation, so the stainless steel elbow, especially the thin-walled stainless steel elbow forming, is mostly manufactured by this process. The precision of the inner and outer molds used in the stamping elbow process is high; the wall thickness deviation of the billet is also demanding.
Roller method: The core is placed in the tube of the stainless steel elbow, and the outer circumference is pressed by the roller for the round edge processing.
Source: China Stainless Steel Elbows Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)