A method for manufacturing a high precision hollow metallic component, by obtaining, through extruding or roll forming, a precursor hollow metallic profile having a constant cross section and at least one precursor chamber; positioning the precursor hollow metallic profile in a split-die cavity, wherein at least two walls of said split die cavity have essentially outside dimensions of corresponding walls of the high-precision hollow metallic component; introducing a mandrel made of at least two parts into the precursor chamber; plastically deforming the precursor hollow metallic profile by expanding the mandrel to obtain finished dimensions of the high-precision hollow metallic component; removing the mandrel from the finished chamber after reversing an expanding action. A variable cross section hollow metallic component, with at least two chambers obtained with the method, is also described.

A hollow shaft includes a cylindrical main body part and an extremity drawn part that is integrally connected to one end of the main body part on the same axis and whose diameter is made smaller than a diameter of the main body part by drawing processing, wherein an inner peripheral face of the main body part and an inner peripheral face of a base portion, which is continuous with one end side of the main body part, of the extremity drawn part are formed as cut faces that are subjected to cutting processing before the drawing processing, and an inner peripheral face of a tip portion, which is continuous with an extremity side of the base portion, of the extremity drawn part is a non-cut face. Accordingly, the hollow shaft can be molded with high shape precision while maintaining a low drawing ratio for an extremity drawn part.

A hollow shaft includes a cylindrical main body part and an extremity drawn part that is integrally connected to one end of the main body part on the same axis and whose diameter is made smaller than a diameter of the main body part by drawing processing, wherein an inner peripheral face of the main body part and an inner peripheral face of a base portion, which is continuous with one end side of the main body part, of the extremity drawn part are formed as cut faces that are subjected to cutting processing before the drawing processing, and an inner peripheral face of a tip portion, which is continuous with an extremity side of the base portion, of the extremity drawn part is a non-cut face. Accordingly, the hollow shaft can be molded with high shape precision while maintaining a low drawing ratio for an extremity drawn part.

A support may include a hollow metallic tube extending over an axis and may include two opposing ends. The tube may include a plurality of sections disposed along the axis. A first section may be disposed at an end of the tube and include a first inner diameter, a first outer diameter, and a first wall thickness. A second section may be separated from the first section via a first transition zone. The second section may include a second inner diameter, a second outer diameter, and a second wall thickness. A third section may be disposed remote from the first section and be separated from the second section via a second transition zone. The third section may have a third inner diameter, a third outer diameter, and a third wall thickness. The wall thickness, inner diameter and outer diameter may vary along the tube between the plurality of sections.

Disclosed herein is an apparatus for the continuous and progressive shaping of metal strips to produce a formed metal strip whose cross sectional dimensions vary along a longitudinal axis thereof. The apparatus includes a device for shaping the metal strips, wherein the device has at least one tool set with at least two rotatably mounted and mutually associated tools, wherein the tools each have a pressure face disposed along an outer circumference thereof with a contour configured to shape the workpieces. The contour of the pressure face of at least one tool is not axially symmetric. In order to be able to cost-effectively produce workpieces or profiles with a variable cross section, in particular profiles with a closed cross section, it is proposed that the contours of the pressure faces of all tools, but at least of one tool set, are concave in order to generate a profile having a closed cross section.

Disclosed herein is an apparatus for the continuous and progressive shaping of metal strips to produce a formed metal strip whose cross sectional dimensions vary along a longitudinal axis thereof. The apparatus includes a device for shaping the metal strips, wherein the device has at least one tool set with at least two rotatably mounted and mutually associated tools, wherein the tools each have a pressure face disposed along an outer circumference thereof with a contour configured to shape the workpieces. The contour of the pressure face of at least one tool is not axially symmetric. In order to be able to cost-effectively produce workpieces or profiles with a variable cross section, in particular profiles with a closed cross section, it is proposed that the contours of the pressure faces of all tools, but at least of one tool set, are concave in order to generate a profile having a closed cross section.

In a steel pipe having a waveform shape formed on an outer diameter thereof by a pipe expansion process, a value a/w is 0.038% or less, where a and w denote an amplitude and a wavelength of the waveform shape, respectively. A method of manufacturing a steel pipe having a waveform shape formed on an outer diameter thereof by a pipe expansion process includes a step of forming the waveform shape such that a value a/w is 0.038% or less, where a and w denote an amplitude and a wavelength of the waveform shape, respectively.

In a steel pipe having a waveform shape formed on an outer diameter thereof by a pipe expansion process, a value a/w is 0.038% or less, where a and w denote an amplitude and a wavelength of the waveform shape, respectively. A method of manufacturing a steel pipe having a waveform shape formed on an outer diameter thereof by a pipe expansion process includes a step of forming the waveform shape such that a value a/w is 0.038% or less, where a and w denote an amplitude and a wavelength of the waveform shape, respectively.

In some embodiments, the instant invention provides for a method including: extruding, utilizing a first die and a mandrel, a hollow tube having a first tube section having a first outer tube diameter of Z, a first inner tube diameter, and a first length; extruding, utilizing a second die and the mandrel, continuing from an end of the first tube section, a hollow tube having a second tube section having a second inner tube diameter and a second length, where the second die has a first die section, and where an angle of a wall of the first die section of the second die relative to a longitudinal axis of the hollow tube ranges from 10 to 45 degrees; extruding a third tube section, a third inner tube diameter, and a third length, and producing a monolithic hollow stepped tube extrudate.

In some embodiments, the instant invention provides for a method including: extruding, utilizing a first die and a mandrel, a hollow tube having a first tube section having a first outer tube diameter of Z, a first inner tube diameter, and a first length; extruding, utilizing a second die and the mandrel, continuing from an end of the first tube section, a hollow tube having a second tube section having a second inner tube diameter and a second length, where the second die has a first die section, and where an angle of a wall of the first die section of the second die relative to a longitudinal axis of the hollow tube ranges from 10 to 45 degrees; extruding a third tube section, a third inner tube diameter, and a third length, and producing a monolithic hollow stepped tube extrudate.