The present invention relates to a tubular element for a gas pressure container of an airbag system of a motor vehicle, wherein the tubular element (10) has at least one first length section (100, 101) and at least one recess (11) extending in the circumferential direction, characterized in that the tubular element (10) has at least one second length section (102), formed by the recess (11) extending over at least a part of the circumference of the tubular element (10), that the second length section (102) lies between two first length sections (100, 101), that in at least one first length section (100, 101) the outer radius (A1) of the tubular element (10) is greater than the smallest outer radius (A2) of the at least one second length section (102), that the tubular element (10) has a tensile strength of >920 MPa, that the wall thickness (W2) of the tubular element (10) in the at least one second length section (102) is thicker than or equal to the wall thickness (W1) in at least one first length section (100, 101) of the tubular element (10), that the degree of reduction of the outer radius (A2) in the recess (11) lies in the range of 5 to 35% relative to the outer radius (A1) of at least one first length section (100, 101), and that the tubular element (10) consists of a material which, in addition to iron and impurities due to melting, comprises the following alloying elements in the ranges indicated in percent by weight: C 0.05-0.2% Si0.9% Mn 0.2-2.0% Cr 0.05-2% Mo<0.5% Ni<1.0% Nb 0.005-0.10% Al<0.07% Ti<0.035% and B<0.004%.

A device for cold working pipe elements has two or more cams, each having a gear. The gears turn synchronously with one another. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A discontinuity in each cam surface is aligned with a gap in the traction surface of each cam. The discontinuities and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated.

A device for cold working pipe elements has two or more cams, each having a gear, the gears being synchronized to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. One or more cams may also have a traction surface extending around a cam body. A discontinuity in each cam surface is aligned with a gap in the traction surface of each cam. The discontinuities and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated. An engagement body is mounted between the cams to engage and disengage from a stop surface on one of the cams. Engagement between the engagement body and a stop surface prevents rotation of the cams.

A device for cold working pipe elements has two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A discontinuity in each cam surface is aligned with a gap in the traction surface of each cam. The discontinuities and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated. A cup adjacent the pinion is movable along the pinion axis to engage and disengage from a stop surface on one of the cams. Engagement between the cup and a stop surface prevents rotation of the cam.

A device for cold working pipe elements has two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A discontinuity in each cam surface is aligned with a gap in the traction surface of each cam. The discontinuities and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated.

A device for cold working pipe elements has two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A discontinuity in each cam surface is aligned with a gap in the traction surface of each cam. The discontinuities and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated.

A device for cold working pipe elements has two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A discontinuity in each cam surface is aligned with a gap in the traction surface of each cam. The discontinuities and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated. A cup adjacent the pinion is movable along the pinion axis to engage and disengage from a stop surface on one of the cams. Engagement between the cup and a stop surface prevents rotation of the cam.

A method for cold working pipe elements use two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may also have a region of constant radius extending around a cam body. Each cam may also have a traction surface extending around a cam body. The method includes contacting the pipe element with a plurality of cam surfaces simultaneously at a plurality of locations on the pipe element and rotating the pipe element, thereby simultaneously rotating the cam surfaces. Each cam surface engages the pipe element with an increasing radius and a region of constant radius if present to deform the pipe element and form the groove.

A tubular element for a gas pressure container of an airbag system of a motor vehicle, wherein the tubular element (10) consists of a material which, in addition to iron and impurities due to melting, comprises the following alloying elements in the ranges indicated in percent by weight: TABLE-US-00001 C 0.05-0.2% Si 0.9% Mn 0.2-2.0% Cr 0.05-2% Mo <0.5% Ni <1.0% Nb 0.005-0.10% Al <0.07% Ti <0.035% and B <0.004%.

A device for cold working pipe elements has two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A region of reduced radius in each cam surface is aligned with a gap in the traction surface of each cam. The regions of reduced radius and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated.