In some implementations, an apparatus comprises a pipe, a stud that is forge-welded to the pipe, creating a forge-welded stud, a bracket that is operably coupled to the forge-welded stud, and a walkway operably coupled to the bracket.

A method of forming an assembly in which a metal extension element is connected with a metal stub element, by an intermediate element. The intermediate element extends between first and second ends. The intermediate element is positioned to locate its first end spaced apart from the stub element. An inner end of the extension element is spaced apart from the second end of the intermediate element. Heating elements are located between the elements, to heat the proximal portions of the elements to a hot working temperature, at which the heated portions are subject to plastic deformation. The heating elements are removed, and while the intermediate element is rotating, the first end is urged against the stub element to bond the intermediate element with the stub element. While the extension element is rotating, the inner end is urged against the second end to bond the extension element and the intermediate element.

Provided is a method of manufacturing a heat exchanger by diffusion bonding in which deformation of bonding members as stainless steel plates is suppressed, and releasability (detachability of a bonding member from a release member) after diffusion bonding treatment is excellent. Provided is a method of manufacturing a heat exchanger, the method including layering a plurality of bonding members 1 made of stainless steel, and applying heat and pressure to effect diffusion bonding of the bonding members 1, in which release members 3 are arranged on the both surface sides of the bonding members 1, and holding jigs 4 are arranged so as to sandwich the bonding members 1 through the release members 3, and pressing is then performed through the holding jigs 4 with a pressure device, and in which the diffusion bonding is performed using a combination of the release members 3 and the bonding members 1, the release members 3 including a steel material containing 1.5 mass % or more of Si, and a ratio (Fr/Fp) of the high-temperature strength (Fr) of the release members 3 at 1000 C. to the high-temperature strength (Fp) of the bonding members 1 at 1000 C. being 0.9 or more.

A constructing-and-forging method for preparing homogenized forged pieces comprises: preparing preformed billets: cutting off a plurality of continuous casting billets, milling and smoothing surfaces of the billets to be welded, performing vacuum plasma cleaning operation to the surfaces to be welded, stacking the plurality of billets and sealing around the surfaces in a vacuum chamber by electron beam welding; forge-welding and homogenizing the preformed billets: heating the preformed billets to a certain temperature in a heating furnace and taking the heated preformed billets out of the heating furnace, forging the preformed billets by a hydraulic press, then using three-dimensional forging to disperse the welded surfaces such that composition, structure and inclusion of the interface areas are at the same level as those of the bodies of the billets. Cheap continuous casting billets are stacked and forge welded.

A method and a system of forming a workpiece assembly including an intermediate element between first and second workpieces. A ring element is included in or on the intermediate element. The ring element is for rotating the intermediate element about the intermediate elements axis. With heating elements positioned between the intermediate element and the first and second ends of the first and second workpieces, portions of the intermediate element and the first and second workpieces are heated to a predetermined hot working temperature, in an inert (non-oxidizing) atmosphere. While the heated portions are at the predetermined hot working temperature, and while the intermediate element is rotated about its axis, one or both of the first and second workpieces are moved axially, to engage the first and second ends with the intermediate element.

A method and a system of forming a workpiece assembly including an intermediate element between first and second workpieces. A ring element is included in or on the intermediate element. The ring element is for rotating the intermediate element about the intermediate elements axis. With heating elements positioned between the intermediate element and the first and second ends of the first and second workpieces, portions of the intermediate element and the first and second workpieces are heated to a predetermined hot working temperature, in an inert (non-oxidizing) atmosphere. While the heated portions are at the predetermined hot working temperature, and while the intermediate element is rotated about its axis, one or both of the first and second workpieces are moved axially, to engage the first and second ends with the intermediate element.

Provided is a method of manufacturing a heat exchanger by diffusion bonding in which deformation of bonding members as stainless steel plates is suppressed, and releasability (detachability of a bonding member from a release member) after diffusion bonding treatment is excellent. Provided is a method of manufacturing a heat exchanger, the method including layering a plurality of bonding members 1 made of stainless steel, and applying heat and pressure to effect diffusion bonding of the bonding members 1, in which release members 3 are arranged on the both surface sides of the bonding members 1, and holding jigs 4 are arranged so as to sandwich the bonding members 1 through the release members 3, and pressing is then performed through the holding jigs 4 with a pressure device, and in which the diffusion bonding is performed using a combination of the release members 3 and the bonding members 1, the release members 3 including a steel material containing 1.5 mass % or more of Si, and a ratio (Fr/Fp) of the high-temperature strength (Fr) of the release members 3 at 1000 C. to the high-temperature strength (Fp) of the bonding members 1 at 1000 C. being 0.9 or more.

A constructing-and-forging method for preparing homogenized forged pieces comprises: preparing preformed billets: cutting off a plurality of continuous casting billets, milling and smoothing surfaces of the billets to be welded, performing vacuum plasma cleaning operation to the surfaces to be welded, stacking the plurality of billets and sealing around the surfaces in a vacuum chamber by electron beam welding; forge-welding and homogenizing the preformed billets: heating the preformed billets to a certain temperature in a heating furnace and taking the heated preformed billets out of the heating furnace, forging the preformed billets by a hydraulic press, then using three-dimensional forging to disperse the welded surfaces such that composition, structure and inclusion of the interface areas are at the same level as those of the bodies of the billets. Cheap continuous casting billets are stacked and forge welded.

A constructing-and-forging method for preparing homogenized forged pieces comprises: preparing preformed billets: cutting off a plurality of continuous casting billets, milling and smoothing surfaces of the billets to be welded, performing vacuum plasma cleaning operation to the surfaces to be welded, stacking the plurality of billets and sealing around the surfaces in a vacuum chamber by electron beam welding; forge-welding and homogenizing the preformed billets: heating the preformed billets to a certain temperature in a heating furnace and taking the heated preformed billets out of the heating furnace, forging the preformed billets by a hydraulic press, then using three-dimensional forging to disperse the welded surfaces such that composition, structure and inclusion of the interface areas are at the same level as those of the bodies of the billets. Cheap continuous casting billets are stacked and forge welded.

Dual alloy turbine rotors and methods for manufacturing the same are provided. The dual alloy turbine rotor comprises an assembled blade ring and a hub bonded to the assembled blade ring. The assembled blade ring comprises a first alloy selected from the group consisting of a single crystal alloy, a directionally solidified alloy, or an equi-axed alloy. The hub comprises a second alloy. The method comprises positioning a hub within a blade ring to define an interface between the hub and the blade ring. The interface is a non-contacting interface or a contacting interface. The interface is enclosed by a pair of diaphragms. The interface is vacuum sealed. The blade ring is bonded to the hub after the vacuum sealing step.