Conical pipe envelope formation process

Conical pipes belong to a group of economical profiles, which find broad application in various metal products. Until now conical pipes have been manufactured by the following methods: rolling on a two-high mill with impressions of varying depth on the rolls’ perimeter; forging in a lever swaging machine, forming in a combined process of drawing and rolling, and rolling on a skew rolling mill. The manufacturing of conical pipes belongs to complicated engineering processes, and the methods used until now do not allow the meeting of the demand for conical pipes—especially long ones with large cross-wise dimensions, e.g. pipes for lamp posts. This situation makes it reasonable to look for new processes with wider engineering possibilities when compared with the known methods known at present. It seems that the process of conical pipe envelope formation will enable the production of a wide assortment of conical pipes.