Provided is a round billet capable of reducing damage on a piercing plug in a method of producing a seamless metal tube with a Mannesmann process. The round billet (5), for use in a seamless metal tube, to be produced into a seamless metal tube with a Mannesmann process includes a body having a hole (6) formed in an axial direction of the body. The hole (6) includes an aperture (6a) opening at least at one end face of the round billet (5), and a tapered portion (61) continued to the aperture (6a) and having a diameter gradually increasing toward the aperture (6a).

The invention relates to a cross-rolling mill, having a plurality of roll shafts (1), each applying a radially directed rolling force to a workpiece, wherein orientation of a roll axis (w) of at least one of the roll shafts (1) adjustably changes about a first adjustment axis (S1) and a second adjustment axis (S2), wherein an intermediate member (9, 10) is arranged between a rotary baring (4, 5) and a control element (11, 12), and wherein the intermediate member (9, 10) includes a rolling force-transmitting rocker pin (14, 15) having a spherical surface (14a, 14b, 15a, 15b) that provides for pivotal movement in a plurality of directions.

The invention relates to a cross-rolling mill, having a plurality of roll shafts (1), each applying a radially directed rolling force to a workpiece, wherein orientation of a roll axis (w) of at least one of the roll shafts (1) adjustably changes about a first adjustment axis (S1) and a second adjustment axis (S2), wherein an intermediate member (9, 10) is arranged between a rotary baring (4, 5) and a control element (11, 12), and wherein the intermediate member (9, 10) includes a rolling force-transmitting rocker pin (14, 15) having a spherical surface (14a, 14b, 15a, 15b) that provides for pivotal movement in a plurality of directions.

A rolling mill system for Incremental rotary shaping of an elongated workpiece is provided that includes first and second workpiece holders. A support frame has a track with the first and second workpiece holders being movably associated with the track, the workpiece holders and an associated workpiece being movable in unison along the track. A radial chuck is mounted to the frame that includes a plurality of jaws that are movable radially inwardly and outwardly. Each jaw has a tool mounted thereto that is rotatable about an axis of rotation, with the axis of rotation of each tool being oriented at a skew angle relative to the longitudinal axis of a workpiece. A source of electric current and an electrically conductive flow path are provided for flowing electrical current through a workpiece. A controller is provided that is configured to control the operation of each of the first motor, second motor and third motor, and to control the flow of current flowing through the tools to the workpiece.

A rolling mill system for Incremental rotary shaping of an elongated workpiece is provided that includes first and second workpiece holders. A support frame has a track with the first and second workpiece holders being movably associated with the track, the workpiece holders and an associated workpiece being movable in unison along the track. A radial chuck is mounted to the frame that includes a plurality of jaws that are movable radially inwardly and outwardly. Each jaw has a tool mounted thereto that is rotatable about an axis of rotation, with the axis of rotation of each tool being oriented at a skew angle relative to the longitudinal axis of a workpiece. A source of electric current and an electrically conductive flow path are provided for flowing electrical current through a workpiece. A controller is provided that is configured to control the operation of each of the first motor, second motor and third motor, and to control the flow of current flowing through the tools to the workpiece.

A dual phase stainless steel pipe includes tensile yield strength YS.sub.LT of 689.1 MPa to 1000.5 MPa in a pipe axis direction of the dual phase stainless steel pipe, in which the tensile yield strength YS.sub.LT, a compressive yield strength YS.sub.LC in the pipe axis direction, a tensile yield strength YS.sub.CT in a pipe circumferential direction of the dual phase stainless steel pipe, and a compressive yield strength YS.sub.CC in the pipe circumferential direction satisfy all Expressions (1) to (4),
0.90YS.sub.LC/YS.sub.LT1.11(1)
0.90YS.sub.CC/YS.sub.CT1.11(2)
0.90YS.sub.CC/YS.sub.LT1.11(3)
0.90YS.sub.CT/YS.sub.LT1.11(4).

In order to optimize the lubrication of a rolling rod in a process for hot-rolling metallic, elongate hollow bodies (21) by means of the rolling rod (2), which is arranged in the hollow body and to which lubricant is applied before the hot-rolling operation, the lubricant is applied to the rolling rod in solid form.

In order to optimize the lubrication of a rolling rod in a process for hot-rolling metallic, elongate hollow bodies (21) by means of the rolling rod (2), which is arranged in the hollow body and to which lubricant is applied before the hot-rolling operation, the lubricant is applied to the rolling rod in solid form.

A method disclosed herewith is a method for producing a first seamless metal tube with a first wall thickness and a second seamless metal tube with a second wall thickness by using a three-roll-type inclined rolling mill, and the method includes a first inclination rolling step (#5), a setting changing step (#10), and a second inclination rolling step (#15). At the first inclination rolling step, a first workpiece is rolled by the inclined rolling mill. At the setting changing step, a setup condition of the inclined rolling mill is changed in a manner (a) or (b) as described below. At the second inclined rolling step, a second workpiece is rolled by the inclined rolling mill under the changed condition. (a) When the second wall thickness is smaller than the first wall thickness, the cross angle of each of the inclined rolls is made greater than the cross angle set for the first inclination rolling step. (b) When the second wall thickness is larger than the first wall thickness, the cross angle of each of the inclined rolls is made smaller than the cross angle set for the first inclination rolling step.

The state of the art discloses cold rolling mills comprising a roll stand, at least one roll rotatably mounted to the roll stand, a feed clamping saddle for feeding a blank, and a first drive for the feed clamping saddle. Those cold rolling mills have ball spindle drives with a high rate of wear as the drive for the feed clamping saddle. In comparison the object of the present invention is to provide a cold rolling mill whose drive for the feed clamping saddle involves no or only very slight wear and which in addition permits a slow movement of the feed clamping saddle. According to the invention that object is attained by a cold rolling mill which has a direct electromechanical linear drive for the feed clamping saddle.