Method and apparatus for the production of a tubular structure for a gas generator, and gas generator tubular structure

A method of producing, from a tubular body, a tubular component for a gas generator, said method comprising, in the following order:

• providing a forming device having an outer tool with an inner diameter that is smaller than an outer diameter of the tubular body and an inner tool, the inner tool composed of a mandrel bar defining a support surface and a calibrating member arranged at a free end of the mandrel bar and defining a calibrating surface;
• inserting the inner tool into an end portion of the tubular body;
• moving the outer tool over the end portion of the tubular body and reducing the outer diameter of the end portion until an inner circumferential surface of the end portion rests against the support surface of the mandrel bar, without making contact with the calibrating member;
• maintaining contact between the outer tool and the end portion having the reduced outer diameter while sliding the support surface of the inner tool along the inner circumferential surface of the end portion;
• sliding the calibrating surface of the inner tool along the inner circumferential surface of the end portion while supporting the end portion having the reduced outer diameter on the outer tool, thereby calibrating the inner circumferential surface and reducing tangential tensile stress due to the absence of support of the end portion having the reduced outer diameter on the inner tool;
• removing the inner tool from the end portion;
• and
• removing the outer tool from the end portion, thereby producing the tubular component with the calibrated inner circumferential surface.