A low-temperature joining method effectively suppresses reductions in the mechanical properties of a junction of various types of high-tensile steel or aluminum, and of a heat-affected zone; and produces a joint structure. A method for joining two metal materials by forming a joint interface in which the two metal materials face each other at a joint portion and plunge a rotation tool caused to rotate at a prescribed speed into the joint, the method for low-temperature joining of metal materials characterized in that the peripheral velocity of the outermost periphery of the rotation tool is set to 51 mm/s or less, whereby the recrystallization temperature inherent to the metal materials is reduced by introducing a large strain to the joint, and recrystallized grains are generated at the joint interface by setting the joining temperature to less than the recrystallization temperature inherent to the metal materials.

Described are tools useful to produce a friction stir weld, methods of forming a friction stir weld, and assemblies such as electronic devices that include a friction stir weld.

A technique facilitates joining of components without subsequent heat treatments. The components are joined by using a friction stir process which establishes a desired friction stir region at an appropriate location to securely join the desired components. In well applications, various components of sand screen assemblies may be joined by the friction stir process. For example, metal sand screen components may be securely coupled with a corresponding metal base pipe. The joining technique enables retention of the corrosion resistant properties of the materials without applying post weld heat treatments and/or other subsequent treatments.

A friction stir welding system can reduce the likelihood of oxide formation in the work pieces being friction stir welded by forming an inert gas atmosphere in which the friction stir welding process is performed. The friction stir welding system includes one or more inert purge gas sources that direct inert purge gas towards the forming friction stir weld. The inert purge gas can be directed towards the forming weld from both an upper and a lower side, which further reduces the likelihood of oxide formation. Additionally, the friction stir welding system can include one or more housings that contains the inert purge gas about the forming friction stir weld, such as about an upper and lower side of the friction stir weld.

A joining method includes a butting process configured to butt a first metal member and a second metal member each having a front surface with various heights to form therebetween a butt portion with various heights; and a welding process configured to apply a friction stirring to the butt portion by a stirring pin of a rotation tool while only the stirring pin of the rotation tool contacts with the first metal member and the second metal member of the butt portion. The welding process may be configured to insert the stirring pin of the rotation tool into the butt portion from front surfaces of the first metal member and the second metal member and apply the friction stirring to the butt portion while an insertion depth of only the stirring pin is kept approximately constant.

A system, apparatus, or method for joining components is provided. The system applies force along an axis, with a friction pin, to a first substrate, such as with a joiner or joining apparatus. The system also frictionally melts a portion of the first substrate adjacent the friction pin by rotating the friction pin about the axis at a first speed within the first substrate. The system also applies force to the second substrate along the axis and frictionally melts a portion of the second substrate adjacent the friction pin by rotating the friction pin at a second speed within the second substrate. The system embeds a portion of the friction pin within the first substrate and the second substrate. In some configurations, the first speed and the second speed are substantially equivalent. In other configurations, the first speed is different from the second speed.

An object is to provide a friction stir welding method and apparatus that provide sufficient strength and good welding workability by advantageously eliminating plastic flow deficiency generated as a result of insufficient heating of workpieces.

In friction stir welding for steel sheets (3, 3) as workpieces, a pair of facing rotary tools (1, 15) are inserted into a non-welded part from both one surface side and the other surface side of the steel sheets (3, 3), the rotary tools move in a welding direction while rotating, and in addition, a preheating process for heating steel sheets (3, 3) is performed by heating means (5) provided in front of the rotary tools(1, 15). The configuration of the pair of facing rotary tools (1, 15) and the surface temperature, area, position, and so forth of a heated region in the preheating process are strictly controlled.

Disclosed herein are systems, methods, and devices for repairing holes in weld seams created by bobbin friction stir welding tools. A hole may be created when a welding tool or, more specifically, a pin of the tool is removed or otherwise extracted from a weld seam created by the tool. The method may involve inserting a plug (e.g., a rivet) into the hole, reshaping the plug in the hole (e.g., riveting) thereby securing the plug in the component, and creating another weld seam through the plug thereby consuming the plug. In some embodiments, the hole may be reshaped prior to inserting the plug. For example, the hole may be drilled out and/or a countersink may be created on one or both ends of the hole. Furthermore, the plug may extend outside of the hole prior to its reshaping and, in some embodiments, even after reshaping.

There is provided a method for manufacturing a joined body using a rotary tool with a stirring pin to perform friction stirring on a composite body having a first surface and a second surface that is different from the first surface. In the composite body, metal members are combined together in a joined arrangement. The method includes the steps of: forming the composite body by combining the metal members in the arrangement; fixing the composite body in a state where the metal members are combined together; performing friction stir welding by inserting the stirring pin through the first surface into the composite body that has been fixed; rotating the fixed composite body such that the second surface is in a positional relationship to face the rotary tool; and performing friction stir welding by inserting the stirring pin through the second surface into the fixed composite body.

Described are tools useful to produce a friction stir weld, methods of forming a friction stir weld, and assemblies such as electronic devices that include a friction stir weld.