Abstract: A multi-wound stainless steel pipe produced by plastic-deforming a hoop material made of a stainless steel sheet applied with a Cu-brazing material on the surface thereof to a multi-wound pipe and after melting the brazing material between the walls of the multi-wound pipe, cooling the molten brazing material, wherein the Cu-brazing material between the walls and the Cu-brazing material at the surfaces of the inside surface and the outside surface of the pipe are diffused into the base material at a depth of from 0.5 .mu.m to 15 .mu.m and bonded thereto. The multi-wound stainless steel pipe is excellent in the pressure resisting strength and working strength and has a high quality.

Abstract: This the method of manufacturing metal pipes by inserting tin or tin based coating material into the metal pipe, raising the temperature rapidly to over 1000.degree. C. in the high frequency furnace in a non-active, or non-oxide atmospheric gas, or in a reducing gas, to coat the entire interior wall of the metal pipe with tin or tin based alloy, and, then, to cool it at a high rate of cooling.According to this method of manufacturing, a uniform coating is formed in the interior wall of the metal pipe, without giving rise to residuous collection of the coating material, or to the non-formation of coating, and such effects as the prevention of metal corrosion as well as the absence of the weakening of the mechanical strength as vibration resistance and also of pressure resistance may be obtained.

Abstract: A manifold for conveying a high-pressure fuel comprises a main pipe having an axial bore and a plurality of ports formed through its wall, connected with the bore and spaced apart from one another along the length of the pipe, and a plurality of branch pipes each connected at one end thereof with one of the ports. The main pipe is provided with a plurality of short cylindrical projections extending laterally outwardly from its wall and each having an axial bore defining one of the ports. Each projection has an outer end provided with a conical or spherical surface, and an outer peripheral surface provided with a screw thread. Each branch pipe has a diametrically enlarged connecting head having a frustoconical or spherical surface closely fitting the conical or spherical surface of one of the projections.

Abstract: A connection structure for branch pipes in a high-pressure fuel manifold, comprising a plurality of through holes formed in the longitudinal direction in the peripheral wall of a main pipe serving to pass a high-pressure fuel and adapted to communicate with an inner flow passage and branch pipes abutted against the through holes, is prevented from the possibility of entailing leakage of fuel through the portions of connection or separation of the branch pipes from the main pipe by shaping the inner terminal peripheries of the through holes each in the form of an outwardly opening bearing surface, fixing joint pieces on the peripheral wall of the main pipe in such a manner as to enclose the bearing surfaces, allowing pressure head portions formed in advance on the connection terminal parts of the branch pipes as matched to the bearing surfaces to be held in tight contact with the bearing surfaces, and causing nuts incorporated in advance in the branch pipes to be helically engaged with threaded holes formed in

Abstract: A thick-walled composite metal tubing comprising an inner tubular member made of a steel pipe and an outer tubular member made of a carbon steel pipe which are press-fitted together with integration bonding thereof involving disappearance of the boundary interface at least in part of the inner and outer tubular members, and process for producing the same.

Abstract: A pipe assembly comprising a metal pipe having a double flared end and a tube formed from a corrosion resistant material and fitted tightly in the metal pipe. The double flared end includes an inner wall portion defining a seat for a tubular member to which the pipe assembly is connected. The tube has one end held by the inner wall portion. The inner wall portion comprises a conical portion and a cylindrical portion contiguous to the conical portion. The cylindrical portion extends beyond a neck defining the double flared end into the tube and held tightly against the inner surface of the tube.