A manufacturing method is provided for a hollow rack bar made of a hollow shaft material and including a toothed section which has a rack on an outer surface and a shaft section which is thinner than the toothed section. The manufacturing method includes: (i) drawing the hollow shaft material using a die and a plug, and preforming regions of the hollow shaft material including a toothed section formation region configured to become the toothed section and a shaft section formation region configured to become the shaft section so as to have thicknesses according to the respective regions; and (ii) forming the rack at the toothed section formation region of the hollow shaft material which is preformed.

An electric resistance welded steel pipe having an identifiable seam portion and a method for manufacturing the same. The electric resistance welded steel pipe includes a steel pipe portion with a seam portion, which is formed by electric resistance welding, and a coating portion of zinc phosphate. The coating portion covers at least an outer surface side of the steel pipe portion. A part of the coating portion that is immediately above the seam portion forms a color difference portion that has a width W along a pipe circumferential direction of greater than or equal to 0.1 times a wall thickness of the pipe and less than or equal to the wall thickness of the pipe. The color difference portion has a visually identifiable color difference from the other parts of the coating portion.

An electric resistance welded steel pipe having an identifiable seam portion and a method for manufacturing the same. The electric resistance welded steel pipe includes a steel pipe portion with a seam portion, which is formed by electric resistance welding, and a coating portion of zinc phosphate. The coating portion covers at least an outer surface side of the steel pipe portion. A part of the coating portion that is immediately above the seam portion forms a color difference portion that has a width W along a pipe circumferential direction of greater than or equal to 0.1 times a wall thickness of the pipe and less than or equal to the wall thickness of the pipe. The color difference portion has a visually identifiable color difference from the other parts of the coating portion.

A drawing machine (1) for drawing a tube (2), defining a longitudinal axis (Y), comprising a first die (3) for carrying out the drawing of the tube by means of the use of a mandrel (4); a device for varying the inclination (5) of the tube inlet into said first die (3); a second die (6) for carrying out a skin pass operation on the tube, arranged downstream of said first die (3); an in-line system for detecting the eccentricity of the tube; a data processing system (7) for processing signals originating from said detection system and sending input data to said device for varying the inclination (5) of the tube to vary the inclination of the tube so as to correct the eccentricity of the tube in-line; wherein said in-line system for detecting the eccentricity of the tube comprises a first detection head comprising at least three first transducers (8) arranged downstream of said first die (3).

A drawing machine (1) for drawing a tube (2), defining a longitudinal axis (Y), comprising a first die (3) for carrying out the drawing of the tube by means of the use of a mandrel (4); a device for varying the inclination (5) of the tube inlet into said first die (3); a second die (6) for carrying out a skin pass operation on the tube, arranged downstream of said first die (3); an in-line system for detecting the eccentricity of the tube; a data processing system (7) for processing signals originating from said detection system and sending input data to said device for varying the inclination (5) of the tube to vary the inclination of the tube so as to correct the eccentricity of the tube in-line; wherein said in-line system for detecting the eccentricity of the tube comprises a first detection head comprising at least three first transducers (8) arranged downstream of said first die (3).

The present invention relates to a method for forming a hollow 26 of a ferritic FeCrAI alloy into a tube 2. While tubes made of powder metallurgical, dispersion hardened, ferritic FeCrAI alloys are commercially available, hollows made of FeCrAI alloys so far can hardly be formed into tubes of small dimensions. The major reason for the problems in forming hollows of a ferritic FeCrAI alloy into a finished product is that FeCrAI alloys are brittle. It is therefore an aspect of the present invention to provide a tube 2 made of a ferritic FeCrAI alloy having arbitrary small dimensions. Furthermore, it is an aspect of the present invention to provide a machine 1 and a method for forming a tubular hollow 26 into a finished tube 2 of a ferritic FeCrAI alloy. At least one of the above aspects is addressed by a method for forming a hollow into a tube 2 comprising the steps providing the hollow 26 of a ferritic FeCrAI alloy, heating the hollow 26 to a temperature in a range from 90 C. to 150 C., and forming the heated hollow 26 by pilger milling or drawing into the tube.

The present invention relates to a method for forming a hollow 26 of a ferritic FeCrAI alloy into a tube 2. While tubes made of powder metallurgical, dispersion hardened, ferritic FeCrAI alloys are commercially available, hollows made of FeCrAI alloys so far can hardly be formed into tubes of small dimensions. The major reason for the problems in forming hollows of a ferritic FeCrAI alloy into a finished product is that FeCrAI alloys are brittle. It is therefore an aspect of the present invention to provide a tube 2 made of a ferritic FeCrAI alloy having arbitrary small dimensions. Furthermore, it is an aspect of the present invention to provide a machine 1 and a method for forming a tubular hollow 26 into a finished tube 2 of a ferritic FeCrAI alloy. At least one of the above aspects is addressed by a method for forming a hollow into a tube 2 comprising the steps providing the hollow 26 of a ferritic FeCrAI alloy, heating the hollow 26 to a temperature in a range from 90 C. to 150 C., and forming the heated hollow 26 by pilger milling or drawing into the tube.

A drawing machine (1) for drawing a tube (2), defining a longitudinal axis (Y), comprising a first die (3) for carrying out the drawing of the tube by means of the use of a mandrel (4); a device for varying the inclination (5) of the tube inlet into said first die (3); a second die (6) for carrying out a skin pass operation on the tube, arranged downstream of said first die (3); an in-line system for detecting the eccentricity of the tube; a data processing system (7) for processing signals originating from said detection system and sending input data to said device for varying the inclination (5) of the tube to vary the inclination of the tube so as to correct the eccentricity of the tube in-line; wherein said in-line system for detecting the eccentricity of the tube comprises a first detection head comprising at least three first transducers (8) arranged downstream of said first die (3).

A drawing machine (1) for drawing a tube (2), defining a longitudinal axis (Y), comprising a first die (3) for carrying out the drawing of the tube by means of the use of a mandrel (4); a device for varying the inclination (5) of the tube inlet into said first die (3); a second die (6) for carrying out a skin pass operation on the tube, arranged downstream of said first die (3); an in-line system for detecting the eccentricity of the tube; a data processing system (7) for processing signals originating from said detection system and sending input data to said device for varying the inclination (5) of the tube to vary the inclination of the tube so as to correct the eccentricity of the tube in-line; wherein said in-line system for detecting the eccentricity of the tube comprises a first detection head comprising at least three first transducers (8) arranged downstream of said first die (3).

Provided is a thin, narrow tube for use in a biodegradable medical device formed from a round tube made of a magnesium material as the base material, in which a desired outer diameter and an inner diameter are provided with good precision over the entire region in a longitudinal direction and a circumferential direction, and the length of biodegradation time can be controlled without changing a material composition. The thin, narrow tube is a thin, narrow tube of a biodegradable medical device, in which the thin, narrow tube is a round tube made of crystals containing magnesium (Mg) having a hexagonal crystal structure, and when the crystals forming the round tube are viewed in a round tube axis direction of the round tube, a hexagonal basal plane (0001) is oriented at a predetermined inclination angle with respect to a circumferential direction perpendicular to a radial direction (a direction from an inner surface to an outer surface) of the round tube.