Friction stir welding apparatus, useful for welding two joining members, comprises a tool having a tool shoulder that is rotationally driven with its front-side friction surface under pressure to form a mixing zone

摘要

The friction stir welding apparatus comprises a tool (1) having a tool shoulder. The tool shoulder is rotationally driven with its front-side friction surface under pressure to form a mixing zone (25) with locally plasticized material on one of joining members (5), and is movable to form a weld seam (3) in a feed direction (V). The tool comprises a cleaning profile of the tool shoulder in the feed direction outside the mixing zone. A structural surface (29) of the joining members are pre-treated, especially purified and/or partially covered by an oxide layer. The friction stir welding apparatus comprises a tool (1) having a tool shoulder. The tool shoulder is rotationally driven with its front-side friction surface under pressure to form a mixing zone (25) with locally plasticized material on one of joining members (5), and is movable to form a weld seam (3) in a feed direction (V). The tool comprises a cleaning profile of the tool shoulder in the feed direction outside the mixing zone. A structural surface (29) of the joining members are pre-treated, especially purified and/or partially covered by an oxide layer. The tool is designed rotationally symmetrical, and/or the cleaning profile is formed radially outside the tool shoulder. The cleaning profile is annularly extended around the tool shoulder. The cleaning profile is upstream of a cooling zone in which a mold temperature is lower in the friction surface of the tool shoulder, preferably lower than a threshold temperature range, above which a plastic deformation of the joining members take place. The cleaning profile is extended between the tool shoulder and an outer edge of the tool. The cleaning profile is reset by an axial offset relative to the tool shoulder. The cleaning profile has a particularly smooth-surfaced annular surface that is in a plane parallel to the friction surface of the tool shoulder. The friction surface of the tool shoulder at a transition stage merges into the annular surface, where a step height is 0.1 mm. The tool is inclined at an angle with respect to the joining members perpendicular to a tool position and opposite to the feed direction. A pin coaxially projects along an axis of rotation of the friction surface of the tool shoulder.