Composite tube assemblies and thin-walled tubing are disclosed. In embodiments, the composite tube assemblies include a functional tube and a sacrificial tube disposed within or around the functional tube. The sacrificial tube may be removed by exposure to a corrosive media, without substantially affecting the functional tube. Methods of forming composite tube assemblies and thin-walled tubing are also described.

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.

Changing of a horizontal roll in a horizontal roll stand involving readjustment of an amount of pressing is to be done readily and promptly. In order to achieve this, a horizontal roll stand 10 with a pair of built-in upper and lower horizontal rolls 11 is configured to retreat toward one side across a forming line. A fixed stand 40 stands upright on a counter-retreating side of the forming line. An overhang part 42 of the fixed stand 40 jutting out over the forming line is provided with a pressure device 43 that applies a pressing force to the horizontal rolls 11. The horizontal roll stand 10 includes a horizontal roll housing 12 with an opened top, receives the pressing force from the pressure device 43 via the opened top, and retreats to the outside of the forming line while the pressure device 43 is left on the forming line. The overhang part 42 of the fixed stand 40 is engaged with the horizontal roll housing 12 of the horizontal roll stand 10 to support the horizontal roll housing 12 in the forming line.

To manufacture a high-quality welded pipe, there is provided a welded pipe manufacturing apparatus for manufacturing a welded pipe by bending a metal plate and welding butting end portions of the metal plate. The welded pipe manufacturing apparatus includes a bending unit that bends the metal plate, a light emitter that emits directional light to an inner surface of the metal plate bent by the bending unit, an image capturing unit that captures light emitted by the light emitter and reflected by a surface of the metal plate, and an adjustment assistance unit that assists adjustment of the bending unit in accordance with a shape of the reflected light.

A seam guide assembly configured to maintain the longitudinal edges of a metal strip in position before welding in a welding section of a welded tube roll forming apparatus, the seam guide assembly having a front seam guide tip component, a through channel being provided in the holder, the channel having an inlet opening located on said first side of the holder, adjacent the front seam guide tip component, and an outlet opening located on a second side of the holder, the outlet opening being configured to connect to a vacuum source; a welded tube roll forming apparatus having a vacuum extraction section configured to extract solid particles produced inside the tube during the high frequency induction welding of the tube edges, and being located in the apparatus at a position where the where the edges of the roll formed tube have not yet been welded together; and related method.

The present invention relates to an air conditioner. The air conditioner according to the present embodiment has a refrigeration capacity of 16 kW to 28 kW, inclusive, and uses a single refrigerant R32 as a refrigerant, and a refrigerant pipe therein includes a ductile stainless steel pipe having 1% or less of a delta-ferrite matrix structure with respect to the grain size area thereof.

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 R134a 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 2 kW to 7 kW, inclusive, and uses R410a as a refrigerant circulating therein, and since a refrigerant pipe therein includes a ductile stainless steel pipe made of a material containing, at least, chrome (Cr), nickel (Ni), manganese (Mn) and copper (Cu), 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.