An apparatus line for manufacturing seamless steel pipes and tubes includes: a heating apparatus for heating a steel raw material; a piercing apparatus for piercing the heated steel raw material thus forming a hollow material; and a rolling apparatus for applying working to the hollow material to form a seamless steel pipe having a predetermined shape. A cooling apparatus is arranged on an exit side of the rolling apparatus. A heated steel raw material is worked by the rolling apparatus after being pierced by the piercing apparatus, and thereafter, using a surface temperature of a hollow piece before being cooled by the cooling apparatus as a cooling start temperature, the hollow piece is cooled to a cooling stop temperature differing by 50° C. or more from the cooling start temperature and being equal to or above 600° C. at an average cooling speed of 1.0° C./s or more in terms of an outer surface temperature.

The present invention relates to a device for guiding a movable element, in particular a driving bar of a mandrel or a mandrel, in a rolling mill with mandrel. The device according to the invention comprises a support structure for the advancement of the movable element along an advancement direction. The device comprises a first slide and a second slide which are carried by said support structure and are slidable along a transverse direction which is substantially orthogonal to said advancement direction, in which each slide carries two abutment surfaces for guiding the movable element and in which each slide is movable along said transverse direction between at least a first operating position, upon reaching which said abutment surfaces are susceptible to coming into contact with a movable element of a first predefined diameter, and at least a second operating position, upon reaching which said abutment surfaces are susceptible to coming into contact with a movable element of a second predefined diameter. According to the invention, the device comprises actuating means which move the slides along the transverse direction between the operating positions and lock the slides themselves when one of said operating positions is reached.

The present invention relates to a device for guiding a movable element, in particular a driving bar of a mandrel or a mandrel, in a rolling mill with mandrel. The device according to the invention comprises a support structure for the advancement of the movable element along an advancement direction. The device comprises a first slide and a second slide which are carried by said support structure and are slidable along a transverse direction which is substantially orthogonal to said advancement direction, in which each slide carries two abutment surfaces for guiding the movable element and in which each slide is movable along said transverse direction between at least a first operating position, upon reaching which said abutment surfaces are susceptible to coming into contact with a movable element of a first predefined diameter, and at least a second operating position, upon reaching which said abutment surfaces are susceptible to coming into contact with a movable element of a second predefined diameter. According to the invention, the device comprises actuating means which move the slides along the transverse direction between the operating positions and lock the slides themselves when one of said operating positions is reached.

A mandrel with a compensating segment, gripper bar, and external body segment making up a key piece configuration. The configuration adjusting the travel path of metal sheet being wound around the mandrel. The metal sheet thereby being wound without resulting imperfections which occur naturally when wrapping material around a cylinder.

A mandrel with a compensating segment, gripper bar, and external body segment making up a key piece configuration. The configuration adjusting the travel path of metal sheet being wound around the mandrel. The metal sheet thereby being wound without resulting imperfections which occur naturally when wrapping material around a cylinder.

A rolling mill for rolling hollow or, in all cases, concave rod-shaped bodies, in particular tubes, in particular seamless tubes, said rolling mill comprising a rolling section (10) with a plurality of mill stands and/or rolling dies (11) arranged in succession to define a rolling axis Y, said rolling mill further comprising moving means for moving a mandrel (20) and a tubular blank (21) fitted onto an end portion (22) of said mandrel (20) along said rolling axis and through said mill stands or rolling dies (11) in succession; wherein said moving means are structured so as to move said mandrel (20) and said blank (21) along said rolling axis Y and through said mill stands or rolling dies (11) in succession by applying a traction on said mandrel.

A stretch reducing rolling mill for rolling pipes has a plurality of roll stands arranged in series in a conveying direction of a pipe. A wall thickness measuring device determines a wall thickness progression of the pipe prior to rolling. A control unit controls respective rotational speeds of the roll stands. A pipe position measuring device is arranged in front of the roll stands and continuously measures a current longitudinal coordinate of the pipe. The measured values of the longitudinal coordinate of the pipe are transmitted to the control unit. The control unit controls the rotational speeds of the roll stands based on both the determined wall thickness progression and the transmitted measured values of the current longitudinal coordinate of the pipe, in order to compensate for wall thickness variations of the pipe. A stretch reducing rolling mill is designed to carry out the method.

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.

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.

A method for producing hot-rolled, seamless pipes having at least one wall thickening which can be arranged at any positions over the length of the pipe, wherein by means of a multiple-stand mandrel bar rolling mill, the rolls roll a hollow shell on a mandrel bar as an inner tool to a required nominal wall thickness and produce at specified positions over the length of the pipe a required wall thickening on the outer side of the pipe by opening the rolls in the rolling stands. The thickened wall is produced and finish-rolled by two rolling stands that are consecutive as seen in the rolling direction, in which the deviations of the finished contour of the thickening from an ideal circular cross-section are minimised, wherein the rolling stands located upstream are likewise opened as to avoid any contact of the rolls of these rolling stands with the previously produced thickening.