The present invention relates to an air conditioner. The air conditioner according to the present embodiment has a refrigeration capacity of 7 kW to 11 kW, inclusive, and uses a refrigerant R32 as a refrigerant, and since a refrigerant pipe therein is made of a ductile stainless steel material having 1% or less of a delta-ferrite matrix structure with respect to the grain size area thereof, and includes a suction pipe guiding the suction of the refrigerant into a compressor and having an outer diameter of 15.88 mm, the refrigerant pipe can maintain strength and hardness as good as or better than those of a copper pipe, while also maintaining good processability.

The present invention relates to an air conditioner. The air conditioner according to the present embodiment has a refrigeration capacity of 11 kW to 16 kW, inclusive, and uses R32 as a refrigerant circulating therein, and since a refrigerant pipe therein is made of a ductile stainless steel material having 1% or less of a delta-ferrite matrix structure with respect to the grain size area thereof, the refrigerant pipe can maintain strength and hardness as good as or better than those of a copper pipe, while also maintaining good processability.

The present invention relates to an air conditioner. The air conditioner according to the present embodiment has a refrigeration capacity of 7 kW to 11 kW, inclusive, and uses, as a refrigerant, a mixed refrigerant containing 50% or more of R32, and since a refrigerant pipe therein is made of a ductile stainless steel material having 1% or less of a delta-ferrite matrix structure with respect to the grain size area thereof, and includes a suction pipe guiding the suction of the refrigerant into a compressor and having an outer diameter of 15.88 mm, the refrigerant pipe can maintain strength and hardness as good as or better than those of a copper pipe, while also maintaining good processability.

A method of making a heat exchanger that includes providing a plurality of tubes. Each of the plurality of tubes has exterior cladding on an exterior surface, interior cladding on an interior surface, and a weld seam extending along the length of the plurality of tubes. The method further includes arranging the plurality of tubes such that each of the plurality of tubes is inserted into a corresponding header slot with the weld seams of each of the plurality of tubes oriented downward with respect to gravity, and brazing each of the plurality of tubes and the header after each tube has been inserted into a corresponding header slot. The brazing causes the interior cladding to melt and pool inside the plurality of tubes and along an interior side of the weld seams to form a clad cover portion encases debris generated while forming the weld seams.

A position detection device for a seam portion and a heated portion of a welded steel pipe detects a position of the seam portion of the welded steel pipe and a position of the heated portion generated by heating the seam portion and/or near the seam portion, and includes: an irradiation unit configured to emit light; an imaging device configured to capture a first image of the seam portion and the heated portion irradiated with light and a second image of the seam portion and the heated portion not irradiated with light; and a control device configured to control light irradiation by the irradiation unit and an imaging timing of the imaging device.

This disclosure relates to a method for manufacturing a double pipe, including: a primary roll forming step of forming bending portions on both sides of a strip for an external pipe in a longitudinal direction; a stacking step of stacking a strip for an internal pipe on the strip for the external pipe; a secondary roll forming step of mechanically coupling the strip for the external pipe and the strip for the internal pipe; a forming step of forming the strip for the external pipe and the strip for the internal pipe, mechanically coupled to each other, into a pipe shape; a welding step of bonding the bending portions on both sides of the strip for the external pipe, and the strip for the internal pipe, which are formed into the pipe shape; and a heat treatment step of heat-treating bonded portions of the strip.

A tubular member includes a tube body, a tube end, an exterior surface, an interior surface, a nominal wall thickness, a longitudinal axis, a welded seam, and a patch of material. The welded seam forms an arcuate portion of the interior surface, and the patch covers a portion of the interior surface that includes a portion of the welded seam, extending from the tube end to an axially spaced first location. The resulting interior surface from the tube end to the axially spaced first location has a uniform inside diameter.

An object is to prolong the life of a ring tool, and improve the productivity of a welded pipe. A ring tool unit is held in a downstream-side end portion of a mandrel to be inserted into a welded pipe currently being manufactured from the upstream side of a welding position, and is used as a cutting tool for continuously cutting a bead produced on the inner surface of the welded pipe, wherein the ring tool unit is formed by fitting a ring tool having a ring-like blade in a sleeve having a circular hole for holding the outer circumference of the ring tool.

An external weld bead removal system for removing and chopping an external weld bead from a tube includes a weld bead cutting apparatus and a weld bead chopper apparatus for chopping the removed external weld bead. The weld bead cutting apparatus includes a cutting tool operative to cut and remove an external weld bead from a tube. The weld bead chopper apparatus, the weld bead chopper apparatus includes a first blade member, a second blade member mounted adjacent the first blade member, and a chopper actuator operable to forcibly rotate the first blade member about a rotation axis relative to the second blade member such that the first and second blade members cooperatively cut the removed external weld bead into smaller weld bead segments as the removed external weld bead is advanced through the chopper apparatus.

A steel strip is formed into a cylinder so that opposite ends of the steel strip face each other, while continuously conveying the steel strip. The opposite ends are melted across the entire thickness by irradiating the opposite ends with a high-energy-density beam while applying a pressure with squeeze rolls. A seam is formed by joining the opposite ends, and excess weld metal of the seam on the outer and inner sides of the obtained welded steel pipe is removed by cutting. A repaired seam is then formed by remelting and solidifying a region on the inner side of the welded steel pipe, the region having a depth of 0.5 mm or more from the surface and a width of double or more the width of the seam, and in addition, the center line of the seam is made to coincide with the center line of the repaired seam.