A shaft assembly comprises a hollow shaft and at least one working component disposed therein. A method of forming the shaft assembly includes a step of providing at least one generally planar preform. The preform is then formed into a “U”-shaped partial cylinder. One or more working components may then be assembled and connected to an interior of the partial cylinder. The partial cylinder is then further formed into a hollow cylinder having a generally circular cross-sectional shape, thus surrounding the one or more working components to secure a position thereof in an interior of the hollow cylinder. The hollow cylinder may then be held stationary and a welding operation performed thereon to form the hollow shaft. Once the hollow shaft is welded, post process machining may then be performed thereon as desired to further finish the hollow shaft.

A method of monitoring in real time pressure resistance welding of a cladding tube and an end plug. The method includes: a first step of detecting welding information including voltage, current, and welding force in a process of pressure resistance welding of a cladding tube and an end plug; a second step of comparing static factors obtained by calculating effective values for the welding information with predetermined reference values, respectively; a third step of calculating dynamic factors for the welding information including the gradient of instantaneous welding force, when the reference values are satisfied in the second step; and a fourth step of determining whether there is defect or not in welding quality by comparing the dynamic factors.

A long steel pipe for reel-lay installation formed of electric resistance welded (ERW) steel pipes and having high buckling resistance and a method for producing the long steel pipe for reel-lay installation are provided. The long steel pipe is formed by successively butt-joining longitudinal ends of the ERW steel pipes by girth welding so that girth welds are formed. The ERW steel pipes are successively butt-joined in the pipe longitudinal direction such that the 0 o'clock cross-sectional position or the 6 o'clock cross-sectional position of one of adjacent ERW steel pipes faces an area from the 2 o'clock cross-sectional position to the 4 o'clock cross-sectional position or an area from the 8 o'clock cross-sectional position to the 10 o'clock cross-sectional position of the other of the adjacent ERW steel pipes.

A long steel pipe for reel-lay installation formed of electric resistance welded (ERW) steel pipes and having high buckling resistance and a method for producing the long steel pipe for reel-lay installation are provided. The long steel pipe is formed by successively butt-joining longitudinal ends of the ERW steel pipes by girth welding so that girth welds are formed. The ERW steel pipes are successively butt-joined in the pipe longitudinal direction such that the 0 o'clock cross-sectional position or the 6 o'clock cross-sectional position of one of adjacent ERW steel pipes faces an area from the 2 o'clock cross-sectional position to the 4 o'clock cross-sectional position or an area from the 8 o'clock cross-sectional position to the 10 o'clock cross-sectional position of the other of the adjacent ERW steel pipes.

A self-propelled welding machine for butt welding pipes, comprising a chassis having a traction means which allows its movement along a direction of travel; the chassis supports a welding apparatus comprising a first clamping unit and a second clamping unit, adapted to respectively engage a first tubular element and a second tubular element to be joined by welding; a device for milling the ends of the first and second tubular elements and a heating plate for welding the ends are associated or associable with the welding apparatus; the particularity of the self-propelled welding machine resides in that it comprises at least one first blade associated with a first end of the chassis; the first blade is arranged transversely with respect to the direction of travel and is movable with respect to the chassis.

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.

There are provided an electric resistance welded steel pipe for producing a high strength hollow stabilizer excellent in fatigue resistance and a high strength hollow stabilizer. In an electric resistance welded steel pipe (5) for producing a hollow stabilizer, an internal weld bead cut portion (30) has a three-peak shape and a depth (H) of a trough portion (30a) of the three-peak shape is 0.3 mm or less and an angle (θ) formed by a central portion in the circumferential direction of the trough portion (30a) and the top of right and left peak portions (30b, 30c) located on both the right and left sides of the trough portion (30a) is 160° or more and less than 180°.

An electrode unit of a joining apparatus includes an abutting section provided with a tapered outer circumferential surface that contacts a tapered pressure-receiving surface by being inserted into an inside of a first metal member. The tapered outer circumferential surface inclines in a direction of getting closer to an axial center of the abutting section from one end side to another end side. At least part of the abutting section has a thickness elastically deformable in such a manner that the tapered outer circumferential surface aligns with the tapered pressure-receiving surface during application of a pressurizing force to the first metal member and a second metal member.

There are provided an electric resistance welded steel pipe for producing a high strength hollow stabilizer excellent in fatigue resistance and a high strength hollow stabilizer. In an electric resistance welded steel pipe (5) for producing a hollow stabilizer, an internal weld bead cut portion (30) has a three-peak shape and a depth (H) of a trough portion (30a) of the three-peak shape is 0.3 mm or less and an angle () formed by a central portion in the circumferential direction of the trough portion (30a) and the top of right and left peak portions (30b, 30c) located on both the right and left sides of the trough portion (30a) is 160 or more and less than 180.