PROCESS AND APPARATUS FOR THE COLD SHAPING OF PIPES OR FITTINGS, AND ARTICLES THUS OBTAINED

摘要

A pipe or fitting tubular section (17) is at first deformed so as to obtain at least a radial wall, substantially perpendicular to the pipe axis, and having, as regards the thickness, such a height that its buckling limit load is inferior to its combined bending and compressive limit load; then said pipe is deformed by substantially radial forces acting on a zone adjacent to said radial wall which acts as a support. The radial wall can be supported at its internal base. The radial wall (22, 22a) can be formed by operating shaped radial inserts (40) on the pipe wall or by axially operating one against other two dies that leave the pipe free at a desired point thus creating a collar. A subsequent cold-working can be carried out both by radial inserts and by putting in contact a pipe portion adjacent to said radial wall with a fixed surface which shapes said portion. An axial shaping of the radial wall can be provided axially operating with dies.