A powder lubricant composition according to the present invention includes 65 parts by mass to 95 parts by mass of sodium borate, and 5 parts by mass to 35 parts by mass of cryolite. A method for manufacturing a seamless steel pipe according to the present invention includes adhering the above-described powder lubricant composition to a pipe inner surface of a work piece which is piercing rolled to have a tubular shape, and elongation rolling on the work piece after the adhering of the powder lubricant composition.

A process of producing a duplex stainless steel tube comprises the steps of: a) producing an ingot or a continuous casted billet of said duplex stainless steel; b) hot extruding the ingot or the billet obtained from step a) into a tube; and c) cold rolling the tube obtained from step b) to a final dimension thereof.

The outer diameter D and the wall thickness t of the cold rolled tube is 50-250 mm respectively is 5-25 mm, and, for the cold rolling step, R and Q are set such that the following formula is satisfied:

Rp0.2target=416.53+113.26.Math.log Q+4.0479.Math.R+2694.9.Math.C %82.750.Math.(log Q).sup.20.04279.Math.R.sup.22.2601.Math.log Q.Math.R+16.9.Math.Cr %+26.1.Math.Mo %+83.6.Math.N %+Z(1)

wherein Rp0.2target is targeted yield strength and is 800-1100 MPa and 0<Q<3.6.

A spinning method includes supporting a supported portion of a cylindrical work by a work supporting portion. The method includes pressing a roller of a spinning head against an outer peripheral surface of a processed portion of the work while revolving the roller. The method also includes performing a forming process that points a tube axis of the processed portion of the work in a given direction by moving the processed portion relative to the work supporting portion or moving the work supporting portion relative to the processed portion, while making a core bar inserted into the processed portion of the work contact an inner peripheral surface of the processed portion.

A spinning method includes supporting a supported portion of a cylindrical work by a work supporting portion. The method includes pressing a roller of a spinning head against an outer peripheral surface of a processed portion of the work while revolving the roller. The method also includes performing a forming process that points a tube axis of the processed portion of the work in a given direction by moving the processed portion relative to the work supporting portion or moving the work supporting portion relative to the processed portion, while making a core bar inserted into the processed portion of the work contact an inner peripheral surface of the processed portion.

An integrated transverse rolling mill for rolling seamless tubes with skewed axes comprising a piercing stand (2) with skewed axis rolling rolls for piercing a first tube (7) having a first length which is shorter than the space which separates it from the subsequent finishing stand (3) in cooperation with the stake (6), which has the first piercing tip (20) at its end and the second finishing tip (21) at the finishing stand (3). The finishing stand (3) is arranged downstream of the piercing stand (2) so that during the rolling operations the front end of the first tube (7) may only be gripped by the finishing stand (3) once the rear end of the first tube (7) is no longer gripped by the rolling stand (2).

An integrated transverse rolling mill for rolling seamless tubes with skewed axes comprising a piercing stand (2) with skewed axis rolling rolls for piercing a first tube (7) having a first length which is shorter than the space which separates it from the subsequent finishing stand (3) in cooperation with the stake (6), which has the first piercing tip (20) at its end and the second finishing tip (21) at the finishing stand (3). The finishing stand (3) is arranged downstream of the piercing stand (2) so that during the rolling operations the front end of the first tube (7) may only be gripped by the finishing stand (3) once the rear end of the first tube (7) is no longer gripped by the rolling stand (2).

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 combination of roller tools is used to cold work a pipe element and impart a desired shape to the sidewall. The roller tools are movably mounted on a frame. Segments of the roller tools align with one another during operation. The roller tools are used in a method of roll forming wherein the sidewall of the pipe element is compressed between the rollers.

A combination of roller tools is used to cold work a pipe element and impart a desired shape to the sidewall. The roller tools are movably mounted on a frame. Segments of the roller tools align with one another during operation. The roller tools are used in a method of roll forming wherein the sidewall of the pipe element is compressed between the rollers.