Abstract: After an inner wall tube, made of steel or alloy containing not less than 2% of Cr, whose outer surface thereof is machined and/or ground to a thickness of 0.1 mm or more including the scale layer, is inserted into an outer wall tube, made of ferritic steel containing not less than 2% of Cr, in which an oxide scale layer containing Cr and having a thickness of 10 to 30 ?m is formed in the inner surface thereof, cold working at an outside diameter reduction rate of 5 to 30% is performed. Similarly cold worked after an inner wall tube having an oxide scale layer on the outer surface thereof, is inserted into an outer wall tube whose inner surface is machined and ground. A double-walled tube made has a uniform gap and an excellent thermal conductivity, and is suitable as materials for SG tubes of future FBR.

Abstract: A precursor detection device 6 detects a precursor of a stick-slip phenomenon in a drawing machine 1. The precursor detection device 6 includes a load measurement section 61 for measuring a load applied to a plug support bar 4 in the drawing direction, a precursor detection section 62 for detecting a precursor of a stick-slip phenomenon based on a load measurement value measured by the load measurement section 61, and a control section 63. After drawing is started, a load applied to the plug support bar 4 in the drawing direction is measured by the load measurement section 61 during a predetermined period from a measurement start point to a measurement end point, and based on the measured load measurement values, a precursor of a stick-slip phenomenon is detected by the precursor detection section 62.

Abstract: A production method of a metal pipe which can suppress quenching defects is provided. In the production method of a metal pipe according an embodiment of the present invention bend of the metal pipe is straightened by a straightening machine 10. Next, both pipe end portions of the metal pipe whose bend has been straightened are cut off by a pipe cutting apparatus 20. Next, a plurality of the metal pipes whose both pipe end portions have been cut off are aligned in the axial direction thereof to be conveyed to a quenching apparatus 30, and the metal pipes are quenched by being cooled after being heated by induction heating.

Abstract: Provided is a method for producing a double-wall tube with braided wires at its interface in which the braided wires are interposed between an outer-wall and inner-wall blank tubes and then a drawing process is applied so as for the braided wires to be brought into close contact with the inner surface of the outer-wall tube and the outer surface of the inner-wall tube, the method comprising: polishing the inner surface of the outer-wall blank tube and the outer surface of the inner-wall blank tube so that a surface roughness thereof satisfies Ra<1.0 ?m, followed by interposing the braided wires between the outer-wall and inner-wall blank tubes; performing a sinking drawing process so that the difference of the outer diameter of the resulting double-wall tube relative to a die bore diameter is 0.1 mm to 0.3 mm; and subsequently performing heat treatment. The double-wall tube produced is suitable as a heat-transfer tube.

Abstract: After an inner wall tube, made of steel or alloy containing not less than 2% of Cr, whose outer surface thereof is machined and/or ground to a thickness of 0.1 mm or more including the scale layer, is inserted into an outer wall tube, made of ferritic steel containing not less than 2% of Cr, in which an oxide scale layer containing Cr and having a thickness of 10 to 30 ?m is formed in the inner surface thereof , cold working at an outside diameter reduction rate of 5 to 30% is performed. Similarly cold worked after an inner wall tube having an oxide scale layer on the outer surface thereof, is inserted into an outer wall tube whose inner surface is machined and ground. A double-walled tube made has a uniform gap and an excellent thermal conductivity, and is suitable as materials for SG tubes of future FBR.