A method of laser welding a workpiece stack-up that includes at least two overlapping metal workpieces is disclosed. The method includes advancing a beam spot of a laser beam relative to a top surface of the workpiece stack-up and along a beam travel pattern to form a laser weld joint, which is comprised of resolodified composite metal workpiece material, that fusion welds the metal workpieces together. And, while the beam spot is being advanced along the beam travel pattern, between a first point and a second point, which may or may not encompass the entire beam travel pattern, at least one of the following laser beam parameters is repeatedly varied: (1) the power level of the laser beam; (2) the travel speed of the laser beam; or (3) the focal position of the laser beam relative to the top surface of the workpiece stack-up.

A friction stir spot welding apparatus includes a pin member formed in a solid cylindrical shape, a shoulder member formed in a hollow cylindrical shape, the pin member being inserted in the shoulder member, a rotary actuator that rotates the pin member and the shoulder member on an axis that is in agreement with an axial center of the pin member, and a linear actuator that linearly moves each of the pin member and the shoulder member along the axis. A tip-end part of the shoulder member is formed in a tapered shape.

In an embodiment, a method of forming a cooling plate, comprises laser welding a plurality of weld lines to physically connect a first substrate and a second substrate wherein the plurality of weld lines forms an inflatable track; and inflating the inflatable track with an inflation fluid to form a cooling channel in the cooling plate. In another embodiment, the cooling plate can comprise a first substrate and a second substrate and a plurality of weld lines can form a fluid tight seal for a cooling channel located therebetween.

Provided is a multimaterial joint material that contributes to multimaterialization and a reduction in weight of a transport apparatus, the multimaterial joint material being configured from: a flame-retardant magnesium alloy; and a metal or alloy selected from the group consisting of aluminum alloys, titanium alloys, stainless steel, and steel. This multimaterial joint material is such that two or more layers of different types of metal materials are joined, wherein the multimaterial joint material is characterized in that: of the two or more layers of metal materials, at least one layer comprises a flame-retardant magnesium alloy, and another layer comprises a metal or alloy selected from the group consisting of aluminum alloys, titanium alloys, stainless steel, and steel; and the two or more layers of metal materials are joined together across the entire surface of joining surfaces that overlap each other.

The invention provides a surface treatment method for a magnesium alloy hub. The process includes: cleaning a to-be-treated surface of the magnesium alloy hub; blackening the cleaned to-be-treated surface; and laser cladding the blackened to-be-treated surface, wherein a laser cladding mode is a synchronous powder feeding mode, and a coating material is chromium. According to the surface treatment method for the magnesium alloy hub, air holes can be avoided.

A reinforcing member for cold forming according to an embodiment comprises: a blank member; and a reinforcing patch member provided to cover at least a portion of the blank member and coupled to the blank member by a plurality of welded portions, wherein the entire region of a heat-affected zone formed around the welded portions in the blank member is positioned in a region corresponding to the reinforcing patch member, and a heat-affected zone formed around a first welded portion from among the welded portions may contact the central point of a second welded portion adjacent to the first welded portion or may be formed to be spaced apart from the central point of the second welded portion.

Provided is a joining method that can prevent a plastic flowing material from flowing out from a butt section and that can reduce the thickness and weight of metal members. The joining method is for joining a first metal member and a second metal member by using a rotary tool comprising a stirring pin, and is characterized in that: the stirring pin comprises a flat surface perpendicular to the rotation axis of the rotary tool and comprises a protruding section protruding from the flat face; and in a friction stirring step, the flat surface is brought into contact with the first metal member and the second metal member, and a front end face of the protruding section is inserted deeper than an upper overlapping section to join an upper front butt section and the upper overlapping section.

Main current passage and subsequent current passage are performed, with a cooling time of 0.01 s or more being provided between the main current passage and the subsequent current passage. Ip/I which is a ratio of a current value of the subsequent current passage to a current value of the main current passage is controlled to satisfy a predetermined relationship depending on a constant A defined by Mn content and P content of a steel sheet as a part to be welded, in relation to a welding time Tp of the subsequent current passage, a cooling time T, and the constant A.

A method of laser welding together two or more overlapping metal workpieces (12, 14, or 12, 150, 14) included in a welding region (16) of a workpiece stack-up (10) involves advancing a beam spot (44) of a laser beam (24) relative to a top surface (20) of the workpiece stack-up along a first weld path (72) in a first direction (74) to form an elongated melt puddle (76) and, then, advancing the beam spot (44) of the laser beam (24) along a second weld path (78) in a second direction (80) that is opposite of the first direction while the elongated melt puddle is still in a molten state. The first weld path and the second weld path overlap so that the beam spot of the laser beam is conveyed through the elongated melt puddle when the beam spot is advanced along the second weld path.

The present disclosure provides methods for preparing an extruded product from a solid billet. The methods can include providing an as-cast billet for extrusion; applying a simultaneous rotational shear and axial extrusion force to the as-cast billet to plasticize the as-cast billet; and extruding the plasticized as-cast billet with an extrusion die to form an extruded product. Methods for preparing extruded products from billets can also include: providing a billet for extrusion; while maintaining a majority of the billet below 100° C., applying a simultaneous rotational shear and axial extrusion force to one end of the billet to plasticize the one end of the billet; and extruding the plasticized one end of the billet with an extrusion die to form an extruded product. Methods for preparing an extruded product from a billet can also include providing a billet for extrusion; applying a simultaneous rotational shear and axial extrusion force to the billet to plasticize the billet; extruding the plasticized billet with an extrusion die to form an extruded product; and artificially aging the extruded product for less than the ASTM recommended amount of time.