Method for the multi-axis shaping of a hollow workpiece and supporting core for use in the method

A method for multiaxial forming of a hollow workpiece (W), in particular a square tube (8), a hexagonal tube or another polygonal hollow workpiece (W), comprising:

• a) providing the hollow workpiece (W) to be formed;
• b) inserting a support core (10) into the cavity (H) of the workpiece (W), wherein the support core (10) comprises a central body (11) with differently oriented cylinder bores (13) communicating with one another and with pistons (17) which are accommodated therein and can be pressurized by a pressurized fluid through a fluid connection (21) of the central body (11), the differently oriented cylinder bores (13) being offset from one another in the axial direction and cylinder bores of different orientation not being arranged in a common plane;
• c) radial expanding of the support core (10) while extending the pistons (17) out of the cylinder bores (13) by pressurizing the pistons (17) with pressurized fluid;
• d) inserting the workpiece (W) to be formed into a radial press;
• e) radial forming of the workpiece (W) in the radial press with reduction of at least two radial dimensions;
• f) opening the radial press;
• g) removing the formed workpiece (W) from the radial press;
• and
• h) removing the support core (10) from the cavity (H) of the workpiece (W).