Technological study of the hydraulic extrusion–bulge forming of a three-way tube

The three-way tube is a widely applied basic element in modern industry. Welding, casting, die forging and mechanical working, etc. were adopted in the past. If these above-mentioned backward technologies are adopted, they will have grave shortcomings: great metal loss, low quality of the products, high production cost, and low production efficiency. In this paper, the advantages of replacing the traditional common working methods to produce three-way tubes with the technology of hydraulic extrusion–bulge forming are introduced; the die structure of hydraulic extrusion–bulge forming is elaborated; the main causes of defects in extrusion–bulge forming practical production are pointed out; and the implication factors for the technological design are discussed.