Abstract:
PROBLEM TO BE SOLVED: To provide a heat exchanger capable of improving the connecting reliability while ensuring the arrangement property of an inner fin in a tube. SOLUTION: The tube 122 has a connecting part 125a where a first edge part 122d and a second edge part 122e of a sheet-like member 122B are overlapped only at one end-side curved part 122b in the long axial direction of a substantially elliptic sectional shape, and the inner fin 123 is arranged in the tube 122 before forming the connecting part 125a. the arrangement property of the inner fin 123 is enhanced thereby, and since only one connecting part 125a is used, more satisfactory connecting reliability is provided than in a case of providing connecting parts at both ends. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
This double pipe for a welded structure exhibits excellent weld crack resistance, wherein: said double pipe is composed of an inner pipe that is made of a ferrite heat-resistant steel having a chemical composition comprising specific amounts of C, Si, Mn, P, S, Ni+Cu, Cr, Mo+W, V, Nb, Ti, B, Al, N, and O with the balance comprising Fe and impurities and an outer pipe that is made of an austenite heat-resistant steel having a chemical composition comprising specific amounts of C, Si, Mn, P, S, Ni, Cr, Al, N, and O with the balance comprising Fe and impurities; fillet-welded sections that satisfy the expression [outer pipe thickness >= depth of melt caused by fillet-welding + 0.3mm] are formed on the outer surface of the double pipe; and the thicknesses (mm) of the outer pipe and the inner pipe satisfy the expression [outer pipe thickness / (outer pipe thickness + inner pipe thickness)
Abstract:
PROBLEM TO BE SOLVED: To provide a double pipe for a welded structure, in which the outer surface of a pipe is subjected to fillet welding without performing treatment such as pre-heating and post-heating, capable of being used as the stock of various high temperature components, and having excellent welding crack resistance.SOLUTION: A double pipe for a welded structure is composed of: an inner pipe made of a ferritic heat resistant steel having a chemical composition including specified amounts of C, Si, Mn, P, S, Ni+Cu, Cr, Mo+W, V, Nb, Ti, B, Al, N and O, and the balance Fe with impurities; and an outer pipe made of an austenitic heat resistant steel having a chemical composition including specified amounts of C, Si, Mn, P, S, Ni, Cr, Al, N and O, and the balance Fe with impurities, wherein fillet weld zones satisfying the inequality of [(the thickness of the outer pipe)≥(melting depth by fillet welding)+0.3 mm] are formed at the outer surface thereof, and is used for producing a welded structure, and the thickness (mm) of the outer pipe and the inner pipe satisfies the inequality of [(the thickness of the outer pipe)/((the thickness of the outer pipe)+(the thickness of the inner pipe))≤0.4].
Abstract:
The invention relates to a method for manufacturing finned tubes made of metal, in particular heat exchanger tubes, where at least one continuous strip forming the fins is fed tangentially to a tubular body set into rotational motion, and wound onto it, the side of the strip facing the tubular body is connected to the tube surface by means of a welding device and using a filler material, and the strip to be wound is guided between guide discs just behind the welding area, said discs reaching close up to the tube surface and the welding point. To increase the service life of the guide discs, the guide discs are cooled, specifically with cooling water to which roughly 10% by volume of a welding release agent are added.
Abstract:
PROBLEM TO BE SOLVED: To provide a method of movable surface-friction welding for joining thin plates. SOLUTION: The method is applied in butt-welding two members 1, 2 to be joined. A probe 3 touching on a joint requiring line 5 is rapidly rotated to generate friction heat, so that plastic deformation is caused forcibly drastically in the surfaces of the members 1, 2. The plastic deformation permeates into the insides of materials so that the members 1, 2 are joined. Both members 1, 2 are continuously butt-welded by horizontally moving the probe 3 along the joint requiring line 5. The plastic deformation is generated only by the surface-friction, the deformation permeates into the insides of the members, and the members are joined. Thus, thin plates become weldable, and working defects at an welded end-part caused by using a probe pin are not generated. COPYRIGHT: (C)2005,JPO&NCIPI