A method providing a first tubular workpiece having a first weld surface at an end thereof, and a second tubular workpiece having a second weld surface at an end thereof; aligning the workpieces on a common axis with the weld surfaces facing each other, rotating one workpiece about the axis relative to the other workpiece, and engaging the first and second weld surfaces such that the rotation raises the temperature at the weld surfaces to create a weld interface; and ceasing the rotation and allowing the weld interface to cool to weld the workpieces together at the interface. The first weld surface is an apex region of an annular projection at the end of the first workpiece, on a longitudinal section through the aligned workpieces the annular projection having a profile in which radially inner and outer side surfaces of the annular projection taper towards the apex region.

An electric resistance welded steel pipe for a torsion beam, in which a chemical composition of a base metal portion contains, in terms of % by mass, 0.05 to 0.30% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.010 to 0.200% of Ti, 0.005 to 0.500% of Al, 0.010 to 0.040% of Nb, and 0.0005 to 0.0050 % of B, the balance containing Fe and impurities, wherein: V.sub.c90, defined by the following Formula (i), is from 2 to 150, a mass ratio Ti/N is 3.4 or more, a microstructure of a wall thickness central portion in an L cross section at a base metal 1800 position is a tempered martensite, an average aspect ratio of prior γ grains in the tempered martensite is 2.0 or less, and a tensile strength in the pipe axis direction is from 750 to 980 MPa:
log V.sub.c90=2.94−0.75βa  Formula (i)
βa=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+2Mo  Formula (ii).

An electric resistance welded steel pipe for a torsion beam, in which a chemical composition of a base metal portion contains, in terms of % by mass, 0.05 to 0.30% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.010 to 0.200% of Ti, 0.005 to 0.500% of Al, 0.010 to 0.040% of Nb, and 0.0005 to 0.005(W % of B, the balance containing Fe and impurities, wherein: V.sub.c90, defined by the following Formula (i), is from 2 to 150, a mass ratio Ti/N is 3.4 or more, a microstructure of a wall thickness central portion in an L cross section at a base metal 1800 position is a tempered martensite, an average aspect ratio of prior γ grains in the tempered martensite is 2.0 or less, and a tensile strength in the pipe axis direction is from 750 to 980 MPa:

log V.sub.c90=2.94−0.75βa  Formula (i)

βa=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+2Mo  Formula (ii).

A heat transfer tube as a first refrigerant pipe has a first portion, a first expansion portion, a second portion, a second expansion portion, and a third portion arranged in order. A connecting tube as a second refrigerant pipe has a fourth portion facing the second portion and a fifth portion facing the third portion. The connecting tube is inserted into the heat transfer tube. The inner diameter of the second portion is larger than the inner diameter of the first portion, and the inner diameter of the third portion is larger than the inner diameter of the second portion. The outer diameter of the fifth portion is larger than the outer diameter of the fourth portion. The fifth portion and the third portion are brazed.

A heat transfer tube as a first refrigerant pipe has a first portion, a first expansion portion, a second portion, a second expansion portion, and a third portion arranged in order. A connecting tube as a second refrigerant pipe has a fourth portion facing the second portion and a fifth portion facing the third portion. The connecting tube is inserted into the heat transfer tube. The inner diameter of the second portion is larger than the inner diameter of the first portion, and the inner diameter of the third portion is larger than the inner diameter of the second portion. The outer diameter of the fifth portion is larger than the outer diameter of the fourth portion. The fifth portion and the third portion are brazed.

There is disclosed fluid distribution junctions and methods of assembly therefor. Flexible conduits connect to the junctions, and a consumable subsystem of the junction, conduits and receptacle caps or other connectors may be pre-assembled for ease of use. A subassembly is formed by coupling a plurality of flexible tubular conduits to a plurality of fluid connectors of a fluid junction, the fluid junction having an inner fluid plenum chamber leading to the fluid connectors. Two shells are sandwiched on opposite sides of the subassembly, the shells having mating concave receiving surfaces that together conform around each of the fluid connectors and clamp the tubular conduits onto the circular beads. Juxtaposed joint surfaces on each pair of mating concave receiving surfaces are bonded together such as with sonic welding to make the fluid distribution junction assembly.

There is disclosed fluid distribution junctions and methods of assembly therefor. Flexible conduits connect to the junctions, and a consumable subsystem of the junction, conduits and receptacle caps or other connectors may be pre-assembled for ease of use. A subassembly is formed by coupling a plurality of flexible tubular conduits to a plurality of fluid connectors of a fluid junction, the fluid junction having an inner fluid plenum chamber leading to the fluid connectors. Two shells are sandwiched on opposite sides of the subassembly, the shells having mating concave receiving surfaces that together conform around each of the fluid connectors and clamp the tubular conduits onto the circular beads. Juxtaposed joint surfaces on each pair of mating concave receiving surfaces are bonded together such as with sonic welding to make the fluid distribution junction assembly,

There is disclosed fluid distribution junctions and methods of assembly therefor. Flexible conduits connect to the junctions, and a consumable subsystem of the junction, conduits and receptacle caps or other connectors may be pre-assembled for ease of use. A subassembly is formed by coupling a plurality of flexible tubular conduits to a plurality of fluid connectors of a fluid junction, the fluid junction having an inner fluid plenum chamber leading to the fluid connectors. Two shells are sandwiched on opposite sides of the subassembly, the shells having mating concave receiving surfaces that together conform around each of the fluid connectors and clamp the tubular conduits onto the circular beads. Juxtaposed joint surfaces on each pair of mating concave receiving surfaces are bonded together such as with sonic welding to make the fluid distribution junction assembly.

There are disclosed apparatus including fluid distribution junctions and methods of assembly therefor. Flexible conduits connect to the junctions, and a consumable subsystem of the junction, conduits and receptacle caps or other connectors may be pre-assembled for ease of use. A subassembly is formed by coupling a plurality of flexible tubular conduits to a plurality of fluid connectors of a fluid junction, the fluid junction having an inner fluid plenum chamber leading to the fluid connectors. Two shells are sandwiched on opposite sides of the subassembly, the shells having mating concave receiving surfaces that together conform around each of the fluid connectors and clamp the tubular conduits onto the circular beads. Juxtaposed joint surfaces on each pair of mating concave receiving surfaces are bonded together such as with sonic welding to make the fluid distribution junction assembly.

There are disclosed apparatus including fluid distribution junctions and methods of assembly therefor. Flexible conduits connect to the junctions, and a consumable subsystem of the junction, conduits and receptacle caps or other connectors may be pre-assembled for ease of use. A subassembly is formed by coupling a plurality of flexible tubular conduits to a plurality of fluid connectors of a fluid junction, the fluid junction having an inner fluid plenum chamber leading to the fluid connectors. Two shells are sandwiched on opposite sides of the subassembly, the shells having mating concave receiving surfaces that together conform around each of the fluid connectors and clamp the tubular conduits onto the circular beads. Juxtaposed joint surfaces on each pair of mating concave receiving surfaces are bonded together such as with sonic welding to make the fluid distribution junction assembly.