A system for air quenching a heat treated element comprises a tubular component, an internal air quench device moveably disposed within the interior of the tubular component, and an external air quench device moveably disposed about the tubular component. The internal air quench device comprises a nozzle configured to induce an airflow within the tubular component. The external air quenching device can comprise an annular ring disposed about the tubular component that is configured to generate a cone of air about the tubular component.

Embodiments of the present disclosure are directed to coiled steel tubes and methods of manufacturing coiled steel tubes. In some embodiments, the final microstructures of the coiled steel tubes across all base metal regions, weld joints, and heat affected zones can be homogeneous. Further, the final microstructure of the coiled steel tube can be a mixture of tempered martensite and bainite.

Embodiments of the present disclosure are directed to coiled steel tubes and methods of manufacturing coiled steel tubes. In some embodiments, the final microstructures of the coiled steel tubes across all base metal regions, weld joints, and heat affected zones can be homogeneous. Further, the final microstructure of the coiled steel tube can be a mixture of tempered martensite and bainite.

A system for air quenching a heat treated element comprises a tubular component, an internal air quench device moveably disposed within the interior of the tubular component, and an external air quench device moveably disposed about the tubular component. The internal air quench device comprises a nozzle configured to induce an airflow within the tubular component. The external air quenching device can comprise an annular ring disposed about the tubular component that is configured to generate a cone of air about the tubular component.

A spot welded joint of at least two steel sheets is provided. At least one of the steel sheets presents yield strength above or equal to 600 MPa, an ultimate tensile strength above or equal to 1000 MPa, uniform elongation above or equal to 15%. The base metal chemical composition includes 0.05C0.21%, 4.0Mn7.0%, 0.5Al3.5%, Si2.0%, Ti0.2%, V0.2%, Nb0.2%, P0.025%, B0.0035%, and the spot welded joint contains a molten zone microstructure containing more than 0.5% of Al and containing a surface fraction of segregated areas lower than 1%, said segregated areas being zones larger than 20 m.sup.2 and containing more than the steel nominal phosphorus content.

Provided is an AlFe-alloy plated steel sheet for hot forming, having excellent TWB welding characteristics since excellent hardness uniformity of a TWB weld zone after hot forming is obtained by suitably controlling a batch annealing condition, after plating Al, such that an AlFe-alloy layer is formed; a hot forming member; and manufacturing methods therefor.

A method of working a gas turbine engine component, for example, a turbine airfoil platform having a heat crack, is disclosed. The presented method may allow turbine airfoils to be repaired, modified, manufactured or otherwise worked and subsequently assembled into a turbine section of a gas turbine engine. This method may help to reduce the costs of operating a gas turbine engine by allowing damaged turbine airfoils to be repaired rather than discarded.

A welding apparatus including: a welding unit (20) that includes a pair of electrode wheels (21A, 21B) arranged to face each other with a welding object therebetween; a pressing unit (30) that includes a pair of press rolls (31A, 31B) that are arranged to face each other with the welding object therebetween and press a welded portion of the welding object welded by the electrode wheels (21A, 21B); a cooling unit (40) that supplies a cooling medium toward the welded portion pressed by the press rolls; a heating unit (50) that heats the welded portion cooled by the cooling unit (40); and a moving body (10) that supports the welding unit (20), the pressing unit (30), the cooling unit (40), and the heating unit (50), and reciprocates in a welding direction of the welding object.

A method for bonding metal workpieces includes: (a) heating a plurality of metal workpieces until the metal workpieces are fully annealed; (b) applying pressure to the metal workpieces to compress the metal workpieces together while the metal workpieces are still heated until the metal workpieces fuse together; and (c) actively cooling the metal workpieces while the metal workpieces are compressed together to join the metal workpieces together.

This disclosure relates to weldability of steel alloys that provide weld joints which retain hardness values in a heat affected zone adjacent to a fusion zone and which also have improved resistance to liquid metal embrittlement due to the presence of zinc coatings.