Development and Introduction of Technology and Equipment for Multiple Drawing of Copper Alloy Thin-Walled Tube on a Long Movable Mandrel Without Intermediate Heat Treatment

Thin-walled and extremely thin-walled tubes made of copper alloys, i.e., brass grades L96, L68, L63, LANKMts, and the bronze grades BrOF6.5-0.15, BrOF4-0.25, are in great demand in the aircraft, shipbuilding, automotive, defense, diesel-locomotive building, and instrument-making industries. A promising manufacturing method is multiple drawing on a long movable mandrel without intermediate heat treatment due to such advantages as high total elongation ratios (λ = 3.0–6.0), simplicity of the equipment of the flow line, high productivity equal to 1200–1600 m/h, as well as good pipe surface quality and size precision. These advantages of the new method of manufacturing cold-deformed pipes make it possible to reduce the cyclic nature of manufacturing and processing costs. The work provides a methodological basis of theoretical analysis and design of rational routes for manufacturing colddeformed pipes by multiple deformation without intermediate heat treatment. As an example, the results are presented for calculation of three-fold drawing of thin-walled pipes made of brass grades L96, L68 and L63. Research results are used in the development of innovative technology for pipe manufacture from copper alloys at the PAO Revda Non-Ferrous Metal Processing Plant using a highly efficient three-fold drawing line on a long movable mandrel. One of the versions for line equipment layout is provided.