Abstract: In diffusion bonding a metal pipe 112e and a metal pipe 114e via a bonded interface 116e formed at the end parts, a portion that is inclined with respect to the radial direction of metal pipes 112e and 114e is provided at least at part of bonded interface 116. In this case, the inclination angle &phgr; of bonded interface 116e and the tip angle 2&thgr; of a pipe expansion tool 130 are preferably in the relationship, 0<&phgr;≦&thgr;+60°. In performing pipe expansion of such a metal pipe bonded body 110e, the pipe expansion tool 130 is moved from the metal pipe 112e, at which the inclined portion of junction face 116e is formed to have a protruding shape, towards the metal pipe 114e, at which the inclined portion of junction face 116e is formed to have a recessed shape. Furthermore, the inner diameter at the vicinity of the junction face of the metal pipe junction may be made larger than the inner diameter at positions away from the junction face.

Abstract: A method for inspecting a clad pipe, having the steps of: transmitting longitudinal ultrasonic waves with wide-band characteristic to make it incident on an inner surface of a clad pipe, the clad pipe including a metal pipe with a coarse crystal grain structure and a different kind of clad metal built up on an inner surface thereof; and receiving reflected echoes of the longitudinal ultrasonic waves on the inner surface side thereof. When a flaw generated in an interface between the metal pipe and the different kind of metal is to be detected, the longitudinal ultrasonic waves in a frequency range of 10 to 30 MHz are preferably used as the ultrasonic waves. When the pipe thickness of the clad pipe is to be measured, the longitudinal ultrasonic waves in a frequency range of 2 to 10 MHz are preferably used as the ultrasonic waves.

Abstract: Carbon steel pipes are joined to each other in a non-oxidizing atmosphere by using an insert constituted by a Ni-base alloy or a Fe-base alloy having a melting point which is lower than 1200° C. and a thickness of 80 mm or smaller under conditions that the surface roughness Rmax of the joined surfaces of the carbon steel pipes is 20 &mgr;m or smaller, the joining temperature is not lower than 1250° C. nor higher than 1330° C., duration at the joining temperature is 30 seconds or longer and the pressure is not lower than 2 MPa nor higher than 4 MPa. The expanding operation is performed such that the maximum difference in level of the joined portion is not larger than 25% of the carbon steel pipe and the expansion ratio is 25% or lower.

Abstract: In diffusion bonding a metal pipe 112e and a metal pipe 114e via a bonded interface 116e formed at the end parts, a portion that is inclined with respect to the radial direction of metal pipes 112e and 114e is provided at least at part of bonded interface 116. In this case, the inclination angle &phgr; of bonded interface 116e and the tip angle 2&thgr; of a pipe expansion tool 130 are preferably in the relationship, 0<&phgr;≦&thgr;+60°. In performing pipe expansion of such a metal pipe bonded body 110e, the pipe expansion tool 130 is moved from the metal pipe 112e, at which the inclined portion of junction face 116e is formed to have a protruding shape, towards the metal pipe 114e, at which the inclined portion of junction face 116e is formed to have a recessed shape. Furthermore, the inner diameter at the vicinity of the junction face of the metal pipe junction may be made larger than the inner diameter at positions away from the junction face.

Abstract: A method for evaluating bonding properties of a metallic pipe, the method comprises steps of measuring, in advance of a pipe expansion operation, at least one selected from a degree of shape discontinuity, a degree of defect at a bonding portion, and a degree of change in crystal structure, and comparing a measurement value with a predetermined threshold value to evaluate suitability of the bonding properties for applying pipe expansion.

Abstract: The surface of the member to be inspected is covered with powder deposited by using, for example, static electricity prior to the flaw detection. The member surface is covered so as to be partly exposed by setting the average thickness of the powder layer to 0.1D-0.6D, where D is the average particle diameter of the powder, under an assumption that the powder particles in the powder layer are virtually leveled into a uniform thickness film. Subsequently, the surface region of the member is heated by high frequency induction heating, and then the temperature distribution on the surface is measured with a radiation thermometer. The part for which the temperature measured is different from the surroundings is judged as a flaw. The surface of the member is covered with the powder so that the surface emissivity becomes almost uniform, and the resulting temperature distribution measured with the radiation thermometer becomes almost equal to the real one.

Abstract: The apparatus for making cooled concrete of this invention produces cooled fresh concrete by cooling the aggregate (or gravel). The aggregate is cooled by immersion in a cooling water bath accommodated in a cooling water tank. The cooling water in the tank is cooled by a heat exchanger, which in turn is cooled by a forced cooling device. The aggregate is immersed into the cooling water bath by a supply and ejection apparatus, which also removes the cooled aggregate from the cooling water bath. The cooled aggregate is supplied to a cement mixer where it is mixed to become cooled fresh concrete.

Abstract: With the screw driven into the female-threaded hole which radially extends through the hollow roller and opens to the outer peripheral surface of the cylindrical portion forming a part of the sprocket, the hollow roller is coupled to the sprocket and functions as a drive roller adapted to rotate integrally therewith. When both female-threaded holes have no screw received therein, the hollow roller functions as a free roller which is rotatable with respect to the sprocket.