Development of Hydraulic Bulging Technology of Stainless Steel Elbow

Stainless steel elbows are thin-walled parts, and it is difficult to process thin-walled parts. The development of hydraulic bulging technology provides a new way for the forming and processing of large thin-walled parts. The dieless hydraulic bulging technology is a new type of hydraulic forming technology, which has the obvious characteristics of low cost, short processing cycle and good forming. The basic technological process is as follows: firstly, a flat plate or a rolled single-curvature shell plate is welded into a closed multi-faceted shell. Then pressurize in the closed polyhedral shell, and under the action of internal pressure, the shell produces plastic deformation and gradually tends to the ideal shape. The basic process of a large stainless steel elbow is: blanking→roll bending→welding into a closed ring shell→pressure forming inside the ring shell→section. The usual processing technology is to press multiple shells with a mold, and then complete the welding. Many procedures require different fixtures or molds, high manufacturing costs and long cycles, and large thin-walled parts have extremely poor manufacturability. The development of hydraulic bulging technology provides a new way for the forming and processing of large thin-walled parts.