Apparatuses and methods for repairing a defect in a nuclear reactor are provided. The apparatus includes a body for insertion in a tubular structure, the body includes: an end effector having a weld torch operable to deposit weld material by forming molten weld droplets and depositing the weld droplets the tubular structure. A drive unit includes a brace for selectively anchoring against said tubular structure; at least one linear actuator for moving the apparatus relative to the brace; and a rotational actuator coupled to rotate the weld torch. The method includes inserting a repair apparatus into tubular structure of the nuclear reactor; moving the repair apparatus to a defect location; depositing a protective weld layer over the defect by sequentially depositing weld droplets atop a weld pool on the tubular structure, wherein the protective weld layer bonds to the tubular structure surrounding the defect.

A welding additive for electric arc welding and laser beam welding of mixed joins composed of austenitic and high-manganese-containing and ferritic steel, where the high-manganese-containing steel has a manganese content of at least 7-30% by weight includes the following alloy elements in % by weight: C 0.04-1.0; Mn 7-30; Si≦6; Al≦4; Mo≦2; Ti≦0.5; Zr 0.01-01; B 0.001-0.01; P<0.005; S<0.002; N<0.008; balance iron and unavoidable steel accompanying elements.

A circumferential welded joint of a line pipe is formed by butting against each other end portions of steel pipes having a yield strength according to 5L Specification of API Standards not smaller than 555 N/mm.sup.2 and welding the butted portions in a circumferential direction. A joint strength ratio σ.sub.match=(TS-w/TS-b).Math.(YS-w/YS-b) represented by a product of a ratio between a tensile strength TS-w of a weld metal and a tensile strength TS-b of a base material and a ratio between a yield strength YS-w of the weld metal and a yield strength YS-b of the base material, and a critical equivalent plastic strain ε.sub.p-cri [%] for ductile crack generation in a base material heat affected zone satisfy Equation (1), and the yield strengths YS-w, YS-b of the weld metal and base material satisfy Equation (2).
σ.sub.match>4.85ε.sub.p-cri.sup.−0.31  (1)
YS-w/YS-b≧1.0  (2)

A coupling system is utilized to form a multi-part rocket engine thrust compartment that maintains inner channels within walls of the thrust compartment for regenerative cooling. The coupling system includes an insert joint arranged between joint faces of a first segment and a second segment. The first segment and the second segment include inner edges that, when jointed together, form an inner wall. The joint insert is installed between the first segment and the second segment after the inner wall is formed and coupled to the first segment and the second segment. The joint faces of the first segment and the second segment include extending feature to form a flow passage along with cavities at least partially defined by the joint insert.

Methods for fabricating high-strength aluminum-boron nitride nanotube (Al—BNNT) wires or wire feedstock from Al—BNNT composite raw materials by mechanical deformation using wire drawing and extrusion are provided, as well as large-scale, high-strength Al—BNNT composite components (e.g., with a length on the order of meters (m) and/or a mass on the order of hundreds of kilograms (kg)). The large-scale, high-strength Al—BNNT composite components can be made via wire-based additive manufacturing.

A tube assembly includes at least first and second tubes configured for coupling at respective ends. The first and second tubes each include a base material, and a weld interface at the respective end. The weld interface is proximate to an inner diameter and an outer diameter of the first and second tubes, and includes a weld interface segment extending therebetween. A work hardened weld assembly couples the base material of each of the first and second tubes. The work hardened weld assembly includes a weld fusion zone between the weld interfaces of the first and second tubes and the weld interface segments of the first and second tubes. The weld fusion zone is work hardened and at least the weld interface segments of the first and second tubes are work hardened between the work hardened weld fusion zone and the base material of the first and second tubes.

Granular welding flux delivery devices and strip cladding systems with granular welding flux delivery devices are disclosed. A disclosed example granular welding flux delivery device includes a hopper having: an intake opening to receive granular welding flux; a chute; and an output opening to output the granular welding flux to an electroslag strip cladding process, a submerged arc welding process, or a submerged arc strip cladding process. The example granular welding flux delivery device further includes a chute divider positioned within the chute to reduce an intake rate of granular material through the intake opening by reducing a cross-section of the chute based on a dimension of the chute divider. The disclosed example granular welding flux delivery device includes an adjustable output cover attached to the chute proximate to the output opening to extend or retract a length of the chute by adjusting a location of the output opening along the chute.

Guide device for use in the processing, in particular welding, of curved surfaces, in particular pipe surfaces, comprising a flexible elongate body provided with a guide for processing means; tensioning means for tensioning the flexible body around the curved surface; wherein the flexible body is provided along its length with indicators arranged according to a determined pattern, this pattern being such that a determined position along the flexible body can be inferred on the basis of the detection of the indicators.

A method for manufacturing a shaft body by welding a plurality of shaft members together and forming the shaft body, the method including: a primary tempering step of subjecting a range in at least one of the shaft members, which is in the vicinity of an end of another shaft member side adjacent thereto, to tempering before the shaft members are welded together so that a strength of an end side of a region thereof is lower than a strength at a side which is opposite to the end of the region thereof; a welding step of welding the shaft members together after the primary tempering step; and a secondary tempering step of tempering the vicinity of a weld part between the shaft members after the welding step.

A gas shielded arc welding method includes welding a steel sheet with a tensile strength of 780 MPa or more using a shielding gas containing Ar in an amount of 92 vol. % to 99.5 vol. %. In the gas shielded arc welding method, a value calculated from the following expression (1) is 0.20 or more: {√v/(D/2).sup.2}×10−{(100−C.sub.Ar)×I/v}×0.1 . . . (1), where C.sub.Ar represents an Ar content (vol. %) in the shielding gas, D represents an inner diameter (mm) of a nozzle from which the shielding gas is supplied, v represents a welding speed (cm/min), and I represents a welding current (A).