The forming process of stainless steel seamless elbows is divided into two categories: core process and auxiliary process. Among them, the core process includes hot push forming and stamping forming, and the auxiliary processes include perforation and sizing, and heat treatment.
Core process
Hot push forming: After the tube blank is inserted into the mold, it is pushed and heated by a pusher, and the volume conservation principle is used to ensure uniform wall thickness, which is suitable for batch production of standard caliber elbows.
Stamping forming: It is divided into cold stamping and hot stamping. The press is directly pressed and shaped in the mold. It is mostly used for small batches, special specifications or ultra-thin/thick wall elbows.
Auxiliary process
Piercing and sizing: The tube blank is perforated by three-roller oblique rolling or extrusion, and then the inner diameter is trimmed by a high-speed rotating conical drill bit of the sizing machine to form seamless pipe fittings.
Heat treatment: Eliminate processing stress and restore the mechanical properties of the material (such as solution treatment to improve the intergranular corrosion resistance of 316L).
The combination of core and auxiliary processes enables stainless steel seamless elbows to meet the diverse needs from civil pipelines to industrial high-pressure systems.