A friction stir welding tool, which includes a pin and a shoulder rigidly connected to the pin, for welding components composed of a parent material having a melting point of more than 900° C., in particular steel. To achieve a particularly long service life of the tool even with thick-walled components, it is provided that the shoulder is at least partially composed of a first material and the pin is at least partially composed of a second material. Furthermore, the shoulder is at least partially composed of a first: material and the pin is at least partially composed of a second material. In addition, a method for joining components of one or more parent materials having a melting temperature of more than 900° C. is provided.

To provide a fitting member, an annular member, a joined member and a method of manufacturing the joined member, which prevent occurrence of a not-joined portion. A fitting member 10 has a fitting protrusion 10p which is protruded outward on an outside face 10s. An annular member 20 contains a space 20h in which the fitting member 10 is to be fitted. An annular member 20 has an annular protrusion 20p on an inside face 20f. When the fitting member 10 is fitted into the space 20h at a predetermined depth, the fitting protrusion 10p and the annular protrusion 20p fill not-joined portions which may be generated assuming that they are not provided. A joined member 30 is produced by fitting the fitting member 10 into the space 20h at the predetermined depth, so that a contact portion between the fitting member 10 and the annular member 20 is joined in solid phase.

A steel joined body includes a plurality of steels joined together, the plurality of steels including a joint interface having a carbon concentration of 0.20 mass % or more and 2.10 mass % or less, and the steel joined body including a concentration gradient layer having a carbon concentration decreasing with distance from the joint interface.

Drill collars may be constructed using solid-state welding processes. Solid-state welding produces robust drill collars with high fatigue lifespans and permits individual segments of the drill collar to be optimized based on their intended use. A drill collar may be formed of a first segment with a different material, density, modulus of elasticity and/or geometry than an adjacent second segment fused thereto. If a segment of a drill collar is damaged in use, the damaged segment may be removed and replaced, possibly without de-rating the drill collar. Methods of forming the solid-state welds may include friction welding adjacent segments to one another such that features in each segment are circumferentially aligned when the weld is formed. Supplemental energy sources may provide additional heat at the welded surfaces to ensure the segments are effectively fused.

Disclosed is a clad steel plate with further improved low temperature toughness along with excellent HIC resistance while ensuring a tensile strength of 535 MPa or more. A clad steel plate includes: a base steel; and a clad metal made of a corrosion resistant alloy bonded to one surface of the base steel, in which the base steel has: a chemical composition with appropriately controlled values of ACR and P.sub.HIC; and a steel microstructure in which bainite is present in an area fraction of 94% or more at a ½ thickness position in a thickness direction of the base steel, and with an average crystal grain size of 25 μm or less, and shear strength at a bonded interface between the base steel and the cladding metal is 300 MPa or more.

An embodiment relates to an ultrasonic additive manufacturing process, comprising joining a foil comprising a bulk metallic glass to a substrate; and forming a cladded composite comprising the foil and the substrate; wherein a thickness of the cladded composite is greater than a critical casting thickness of the bulk metallic glass, wherein the cladded composite comprises a cladding layer of the bulk metallic glass on the substrate and the bulk metallic glass comprises approximately 0% crystallinity, approximately 0% porosity, less than 50 MPa thermal stress, approximately 0% distortion, approximately 0 inch heat affected zone, approximately 0% dilution, and a strength of about 2,000-3,500 MPa.

An embodiment relates to an ultrasonic additive manufacturing process, comprising joining a foil comprising a bulk metallic glass to a substrate; and forming a cladded composite comprising the foil and the substrate; wherein a thickness of the cladded composite is greater than a critical casting thickness of the bulk metallic glass, wherein the cladded composite comprises a cladding layer of the bulk metallic glass on the substrate and the bulk metallic glass comprises approximately 0% crystallinity, approximately 0% porosity, less than 50 MPa thermal stress, approximately 0% distortion, approximately 0 inch heat affected zone, approximately 0% dilution, and a strength of about 2,000-3,500 MPa.

A hot formed joined blank includes a first metal blank having an ultimate tensile strength of ≥about 1300 MPa to ≤about 2000 MPa and defining a first surface, a second metal blank having an ultimate tensile strength of ≥about 400 MPa to ≤about 1200 MPa and defining a second coated surface having a coating disposed thereon. The coating includes aluminum and silicon or in alternative variations, zinc. A third surface of the second metal blank is joined to the first surface of the first metal blank to form the hot formed joined blank. A weld nugget is disposed along a boundary between the first and second metal blanks that is configured to join the first and second metal blanks, where the weld nugget optionally includes less than or equal to about 1.5 weight percent aluminum or a microstructure comprising austenite and delta-ferrite.

An interlayered structure for joining of dissimilar materials, includes a first material substrate, a second material substrate having a composition dissimilar from a composition of the first material substrate, and a plurality of interlayers disposed between the first material substrate and the second material substrate, including a first interlayer nearest to the first material substrate and a last interlayer nearest to the second material substrate. The first interlayer has a composition selected to have a maximum solid solubility within the composition of the first material substrate that is greater than or equal to the other interlayers' solubility within the composition of the first material substrate. The last interlayer has a composition selected to have a maximum solid solubility within the composition of the second material substrate that is greater than or equal to the other interlayers' solubility within the composition of the second material substrate. At least one of the plurality of interlayers is a sintered powder interlayer.

An interlayered structure for joining of dissimilar materials, includes a first material substrate, a second material substrate having a composition dissimilar from a composition of the first material substrate, and a plurality of interlayers disposed between the first material substrate and the second material substrate, including a first interlayer nearest to the first material substrate and a last interlayer nearest to the second material substrate. The first interlayer has a composition selected to have a maximum solid solubility within the composition of the first material substrate that is greater than or equal to the other interlayers' solubility within the composition of the first material substrate. The last interlayer has a composition selected to have a maximum solid solubility within the composition of the second material substrate that is greater than or equal to the other interlayers' solubility within the composition of the second material substrate. At least one of the plurality of interlayers is a sintered powder interlayer.