The invention has a feature of comprising a butting process of forming a stepped butted portion and a joining process of performing friction-stir-welding on the stepped butted portion, wherein the rotary tool includes a base side pin having a taper angle larger than a taper angle of a tip side pin, and a pin step portion in a staircase shape is formed on an outer circumferential face of the base side pin, and wherein in the joining process, a rotation direction and a translation method of the rotary tool are set such that the second metal member is on an advancing side, a target angle by which a rotation axis of the rotary tool is inclined toward the second metal member is set such that a burr formed on a front face of the second metal member after the joining process has a thickness between 0 and 130 μm.

An airfoil for a gas turbine engine includes a first portion joined to a second portion along an interface such that at least the first portion establishes an airfoil section and the second portion establishes a root section. The airfoil section includes an airfoil body that extends between leading and trailing edges in a chordwise direction, between pressure and suction sides separated in a thickness direction, and from the root section to a tip portion in a spanwise direction. A recessed region extends inwardly from at least one of the pressure and suction sides. The airfoil body includes at least one rib that bounds a respective pocket within a perimeter of the recessed region. The recessed region and the at least one rib are dimensioned to extend across the interface. A cover skin is coupled to the airfoil body along the at least one rib to enclose the recessed region.

Provided are a simple and effective friction welding method that can suppress increases in hardness of the welded part and reductions in hardness (strength) in the heat affected zone regardless of the composition of ferrous material, and a welded structure obtained with the same. The present invention relates to a friction welding method wherein surfaces to be welded of two metal members (2, 4) to be welded are made to slide in contact with each other. The friction welding method is characterized in that at least one of the metal members (2, 4) to be welded is a ferrous material, and the maximum temperature reached during welding is equal to or less than the A.sub.3 point or equal to or less than the A.sub.cm point of the ferrous material. The maximum temperature reached during welding is preferably equal to or less than the A1 point of the ferrous material.

A linear friction welding system includes a processing circuit configured to execute program instructions stored in a memory to control a first motor using one of a torque and speed control, placing a plurality of timing gears in a configuration wherein a fixed projection of one of the timing gears is at a trail position of a slot of another timing gear such that two power shafts of a cam assembly are rotating in phase and a ram is motionless. The processing circuit further controls a hydraulic press to generate a pressure between two components to be welded with the power shafts rotating in phase, and controls the second motor using the one of the torque and speed control to place the timing gears in a second configuration whereat the fixed projection is at a lead position of the slot thereby forcing the ram to oscillate.

A friction stir welding apparatus is used at a butted portion where a second workpiece is butted against a first workpiece such that the second workpiece is upright on the first workpiece. The friction stir welding apparatus includes: a rotary tool that is plunged into one inner corner of a pair of inner corners that are positioned, at the butted portion, on both sides of the second workpiece, respectively; an inner corner presser that presses the other inner corner of the pair of inner corners; and a mover that moves the rotary tool and the inner corner presser along a direction in which the butted portion extends. The inner corner presser includes a pressing roller that presses the other inner corner while rolling in a state where the inner corner presser is being moved by the mover.

A system for forming a vehicle component includes a first metal sheet having an aperture, a second metal sheet contacting a lower surface of the first metal sheet, an anvil supporting the first and second metal sheets beneath the aperture, and a press bit disposed above the aperture.

Provided are a friction stir welding apparatus and a friction stir welding method capable of highly accurate position control in a Z-axis direction (vertical direction) of a joining tool when a joint target member is subjected to friction stir welding by the friction stir welding apparatus. The friction stir welding apparatus includes a joining tool which consists of a shoulder portion and a probe portion and is inserted into a joint target member to rotate, a joining head which holds the joining tool, an apparatus body which holds the joining head, rotates the joining tool, and moves the joining tool, and a control device which controls an operation of the joining tool, in which the control device has a reference setting mode where a correction reference used for correction of misalignment in the Z-axis direction of the joining tool which occurs when the joint target member is joined by the joining tool is set in a stage before the joining tool is inserted into the joint target member, a joining mode where the joining tool is inserted into the joint target member and the joint target member is joined, and a correction mode where an amount of position fluctuation of a tip of the joining tool with respect to the correction reference which occurs when the joining tool joins the joint target member is measured and correction is performed when the amount of position fluctuation exceeds a predetermined threshold value.

A phase change assembly for a linear friction welding system includes a single input shaft and a single output shaft with respective first and second gears, and a carriage rotatably supporting a third gear operably connected to the first and second gear and one of a roller and a fourth gear operably connected to the first and second gear. A linear actuator is operably connected to the carriage. A first stop is configured to stop movement of the carriage by the linear actuator in a first direction to provide a first predetermined phase relationship between the input shaft and the output shaft, and a second stop is configured to stop movement of the carriage by the linear actuator in a second direction opposite the first direction to provide a second predetermined phase relationship between the input shaft and the output shaft.

A process for welding a first part and a second part, includes: a linear friction step during which the two parts are rubbed against one another in a linear movement, a first cooling step during which the temperature of the parts thus welded is reduced to ambient temperature, a heating step during which the parts thus welded are heated to a temperature above a temperature of transition between a two-phase α-β field and a single-phase β field of the material constituting the two parts, and a second cooling step during which the temperature of the parts thus heated is reduced to ambient temperature. Such a process makes it possible to transform the structure of the welding zone and of the whole part thus produced into a lamellar α structure in a transformed β matrix which exhibits better damage tolerance.

A linear friction welding method capable of accurately controlling a welding temperature and capable of lowering the welding temperature is provided. The present invention is a linear friction welding method comprising: a first step of forming a welded interface by bringing one member into contact with the other member; a second step of repeatedly sliding one member and the other member on the same locus and discharging flash from the welded interface in a state where pressure is applied substantially perpendicularly to the welded interface; and a third step of forming a welded surface by stopping the sliding and setting the pressure to be not less than the yield stress and not more than the tensile strength of one member and/or the other member at a desired welding temperature.