Patent ID: 12220761

DETAILED DESCRIPTION OF THE DISCLOSURE

The foregoing summary, as well as the following detailed description of certain embodiments will be better understood when read in conjunction with the appended drawings. As used herein, an element or step recited in the singular and preceded by the word “a” or “an” should be understood as not necessarily excluding the plural of the elements or steps. Further, references to “one embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular condition can include additional elements not having that condition.

Examples of the present disclosure provide a method and tool for performing friction stir welding (FSW) to secure two elongated work pieces together along a joint. The work pieces may be metal. For example, the work pieces may be metal extrusions. The tool includes a pin that is coupled to a housing and extends from the housing. The pin is designed to extend through a joint line defined between opposing edges of the two work pieces. The tool includes a shoulder that surrounds a portion of the pin such that the joint line is between the shoulder and the housing. The pin and shoulder rotate relative to the housing and the work pieces. The rotation of the pin and shoulder exerts a frictional force on the work pieces, which heats the edges to a plastic state, below the melting point of the work pieces. The edges mix together when in the plastic, malleable state, and form a welded joint upon cooling and solidifying to integrally join the two work pieces. The product of the welding process is a weld structure.

The FSW tool and method described herein may be used to fabricate weld structures that are both strong and lightweight. The strength may be attributable to the material composition and/or structural design of the weld structure. For example, the FSW tool and method may be used to weld two work pieces composed of a high strength metal alloy. Some high strength metal alloys are not able to be welded by fusion due to the formation of defects, such as cracks. The FSW tool and method may be applicable with at least some of these “unweldable” alloys, such as high-strength aluminum alloys. The structural design of the weld structures may contribute to the strength based on the arrangement of interconnected walls. For example, the work pieces in one or more embodiments described herein may be arranged to define an elongated, hollow box shape that extends the length of the work pieces. The hollow box may structurally support the shape of the weld structure, increasing the stiffness and strength of the weld structure relative to a structure that lacks an internal hollow box element. One advantage of the strength of the weld structure is that the walls of the weld structure can be relatively thin while still maintaining a designated strength parameter (e.g., stiffness, etc.). The walls of the weld structures described herein may be thinner than other known structures in the same or similar applications, which reduces material costs and weight. Providing a reduced weight structure is particularly beneficial for aerial applications, such as commercial aircraft. The structure formed using the FSW tool and method described herein may have better quality (e.g., better surface finish, better dimensional accuracy, less deformation, less defects, and/or the like) than other techniques for fabricating elongated structures, such as extruding the structure in its final shape, without welding.

In one example, the weld structure that is formed by friction stir welding two work pieces is a track. For example, the weld structure may be a seat track on a vehicle for securing passenger seats in place within the vehicle. The vehicle may be a road-based vehicle (e.g., bus, truck, van, etc.), an aerial vehicle (e.g., aircraft, helicopter, spacecraft, etc.), a rail-based vehicle (e.g., train), a marine vessel (e.g., cruise ship, yacht, etc.), or the like. For example, multiple passenger seats may be secured to the seat track within a passenger cabin of the vehicle. In a specific example, the FSW device and method described herein may be designed to fabricate a seat track for an aircraft. The embodiments described herein are not limited to aircraft applications, and are not limited to seat tracks. The FSW device and method may be applied to form various different types of elongated structures for different vehicular and/or non-vehicular applications.

FIG.1is a block diagram of a friction stir welding (FSW) machine100according to an embodiment. The FSW machine100includes a FSW tool102, which is a tool that engages the work pieces to perform a FSW process and combine the work pieces at a welded joint. The FSW tool102includes a pin104, a shoulder106, and a housing108. The pin104is mechanically connected (e.g., coupled) to an actuator that rotates the pin104during the FSW process. In an example, the FSW tool102may be a self-reacting type of FSW tool. The FSW tool102may include two opposing components that contain the pin104in a single assembly and move together along the length of the work pieces to create the weld. For example, the work pieces may be sandwiched between the shoulder106and a top surface of the housing108. The pin104may extend through the joint during the welding process.

In the illustrated embodiment, the actuator includes a first spindle110that is powered by one or more power sources112to rotate the pin104. The power source(s)112may include a motor, a battery, a pneumatic tank that includes compressed gas, a hydraulic pump, and/or the like. For example, the power source(s)112may be controlled based on control signals generated by a user input device that controls operation of the FSW machine100. The spindle110and power source(s)112may control the rate at which the pin104rotates, and may vary the rate based on received control signals.

The housing108is coupled to the pin104. For example, a distal segment of the pin104may extend into the housing108. The pin104may rotate relative to the housing108(and the work pieces) during the FSW process. In an embodiment, the housing108does not rotate relative to the work pieces during the FSW process. For example, the housing108does not complete a full 360-degree rotation. In the illustrated embodiment, the shoulder106is mechanically connected (e.g., coupled) to a second actuator that rotates the shoulder106during the FSW process. For example, the second actuator may include a second spindle114that is powered by the one or more power sources112to rotate the shoulder106. Optionally, the rotation of the shoulder106may be independent of the rotation of the pin104. In an example, the pin104may rotate at different times, a different direction, and/or a different rate than the shoulder106. In one setting, the shoulder106and the pin104may be controlled to concurrently rotate at the same rate (e.g., speed) and direction. In an alternative embodiment, the shoulder106may not be rotated during the FSW process. In that case, the pin104rotates relative to the shoulder106, the housing108, and the work pieces.

Optionally, the housing108of the FSW tool102may be connected to one or more cooling lines116which convey a coolant to and/or from the housing108to dissipate heat from the FSW tool102. The heat may be generated from the frictional forces exerted by the FSW tool102on the work pieces and/or frictional forces between moving components within the FSW tool102itself. The coolant may be a fluid, such as a glycol solution. The coolant may be pumped through the cooling line(s)116via a cooling system118. Optionally, the FSW machine100may include a first cooling line that delivers the coolant to the housing108from the cooling system118, and a second cooling line that returns the coolant from the housing108to the cooling system118. The cooling line(s)116may be hoses, tubes, or the like. In a first alternative embodiment, the FSW machine100lacks the cooling system118and coolant, and the cooling line(s)116are metal rods that passively conduct heat away from the housing108. In a second alternative embodiment, the FSW machine100may lack both the cooling system118and cooling line(s)116.

FIG.2is a perspective view of a weld structure200that is formed by the FSW machine100according to an embodiment. The weld structure200(also referred to herein as structure200) is elongated and extends from a first end202of the structure200to a second end204of the structure200, which is opposite the first end202. The structure200may be linear along the length between the first and second ends202,204. The structure200may include a box-shaped portion206that defines an elongated cavity208. The elongated cavity208may extend the entire length of the structure200. The structure200may include one or more wing segments210that project from the box-shaped portion206. The wing segments210may extend the length of the structure200. In the illustrated embodiment, the structure200has four wing segments210. This cross-sectional shape of the structure200is enlarged inFIG.7. The structure200may not be shown to scale inFIG.2. For example, the length of the structure200may be up to, or greater than, 20 feet, 40 feet, or the like. The walls of the box-shaped portion206and/or the wing segments210may be relatively thin. In an example, the thickness may be no greater than 0.25 inches, or even no greater than 0.125 inches. The structure200may have other cross-sectional shapes in other embodiments.

The FSW machine100may weld two work pieces together to form the structure200. For example, a first work piece212and a second work piece214may be positioned relative to one another such that edges of the work pieces212,214define one or more seams, referred to herein as joint lines216. The work pieces212,214may be fixed in place via one or more fixtures. The structure200has two joint lines216in the illustrated embodiment. The joint lines216may extend the length of the structure200. During the FSW process, the FSW tool102may travel along the length of the work pieces212,214, forming weld joints at the joint lines to integrally connect the two work pieces212,214together and define the unitary weld structure200shown inFIG.2.

Referring back toFIG.1, in an embodiment, the FSW machine100may include a propulsion source120that moves the FSW tool102along the length of the work pieces212,214during the FSW process. The propulsion source120may include a powered actuator, a robotic arm, a tool on a suspended track that pulls the FSW tool102, a traction motor that powers rotation of wheels on the FSW tool102to drive along the work pieces212,214, and/or the like. The propulsion source120may control the movement of the FSW tool102during the FSW process at a designated and constant speed. The designated speed may be based on welding conditions to ensure that the FSW tool102provides sufficient attention to each section of the joint line to result in a successfully welded joint that is relatively uniform along the length. The welding conditions may include the rotational speed of the pin104, the material properties of the work pieces212,214, the amount of heat dissipation by the coolant, and/or the like. In an alternative embodiment, the FSW tool102may be manually pushed or pulled along the length of the joint lines216by a human operator during the FSW process.

FIG.3is a perspective view of the FSW tool102according to an embodiment.FIG.4is an elevation view of the FSW tool102shown inFIG.3.FIG.5is a cross-sectional view of the FSW tool102shown inFIG.3. The cross-section inFIG.5is taken along line5-5inFIG.3. The following description collectively refers toFIGS.3through5.

The pin104is linear and extends from a proximal end302of the pin104to a distal end304of the pin104that is opposite the proximal end302. The pin104rotates about a central axis306that extends through the pin104and is parallel with a length of the pin104between the proximal and distal ends302,304. A proximal segment308of the pin104connects to the first spindle110(or another type of actuator assembly that rotates the pin104. The proximal segment308may include helical threads310. A distal segment312of the pin104connects to the housing108. As shown inFIG.5, the distal segment312may extend into the housing108. The distal end304optionally may be within the housing108or may project beyond a bottom side314of the housing108. The distal segment312may include helical threads or another feature for securing the pin104to the housing108. The pin104projects from a top side316of the housing108such that the proximal segment308and the proximal end302are outside of the housing108. In an embodiment, a majority of the length of the pin302is outside of the housing108. The pin104may be composed of a high-strength metal material.

The shoulder106surrounds the pin104. The shoulder106may be shorter than the pin104such that the shoulder106surrounds only a section of the pin104. The shoulder106may be a hollow shell as shown inFIG.5. The shoulder106may be coaxial with the pin104, and may rotate about the pin104(e.g., about the central axis306). The shoulder106may be cylindrical. The shoulder106may not be directly connected to the housing108. For example, during the FSW process, the shoulder106may be spaced apart from the housing108and may contact a different surface of the work pieces212,214than the surface contacted by the housing108, as described with reference toFIG.7. The shoulder106may be composed of a metal material. The material composition of the shoulder106may be the same or different from the composition of the pin104.

In an example, the housing108is box-shaped. The housing108includes the top side316, the bottom side314, a first side wall318, a second side wall320, a first end wall322, and a second end wall324. The housing108may be an assembly of multiple components. For example, the housing108may include a body326that defines the end walls322,324, or at least portions of the end walls322,324. A lower plate328may define at least a portion of the bottom side314. An upper plate330may define at least a portion of the top side316. The first and second side walls318,320may be defined by wear pads332. The body326, upper plate330, lower plate328, and wear pads332may be secured together via fasteners334. The housing108may have different components in alternative embodiments. In an alternative embodiment, the housing108may include the body326and the wear pads332without the discrete upper and lower plates330,328because the body326may be formed to provide the functions of the plates330,328. For example, a top surface of the body326may provide back side weld containment, and a portion of the body326may block the internal bearing from falling out of the housing108.

FIG.6is an enlarged cross-sectional view of a portion of the FSW tool102shown inFIG.5. In an embodiment, the distal segment312of the pin104is connected to a bearing assembly340within the housing108. The bearing assembly340enables the pin104to rotate relative to the housing108while remaining mechanically connected to the housing108. The bearing assembly340may include a bushing342that is fixedly secured to the pin104. For example, the distal segment312may screw into the bushing342and may be retained in the bushing342via a set screw or the like. The bearing assembly340may include a track or race344that is annular and surrounds a portion of the bushing342. The race344contacts the bushing342and enables the bushing342to rotate relative to the race344with low friction. The race344may include ball bearings. The bearing assembly340is incorporated within an interior346of the housing108. The bearing assembly340enables the pin104to rotate without forcing the housing108to rotate. In an embodiment, the housing108does not rotate relative to the work pieces during the FSW process. The bearing race344may be mounted in place within a depression or cavity of the body326that is sized to accommodate the race344. The bushing342may have a flange348that contacts a bottom side of the race344or the body326to retain the bushing342within the race344.

FIG.7is an elevation view of a welding assembly400that includes the FSW tool102and the weld structure200according to an embodiment.FIG.7shows the FSW tool102performing the FSW process on the work pieces212,214that define the weld structure200according to an embodiment. For example, the FSW tool102is positioned to weld a first joint line216A that is defined by opposing edges402,404of respective first flanges406,408of the work pieces212,214. In the illustrated embodiment, the first and second work pieces212,214are replica copies of each other. For example, the work pieces212,214may have shapes that resemble the shape of the Greek letter Pi. The work pieces212,214may also define a second joint line216B that is across the elongated cavity208from the first joint line216A. The FSW tool102is not positioned to weld the second joint line216B in the illustrated orientation. The second joint line216B is defined between edges of second flanges410,412of the first and second work pieces212,214. The FSW tool102may be flipped relative to the structure200to weld the second joint line216B. Alternatively, a second FSW tool102may be used in conjunction with the illustrated FSW tool102to weld the second joint line216B, such as by moving the two FSW tools102in sequence with one in front of the other along the length of the structure200. At least one of the work pieces212,214may have a different shape in an alternative embodiment.

The housing108of the FSW tool102may be sized and shaped to fit within the elongated cavity208of the structure200. For example, the housing108is disposed within the elongated cavity208inFIG.7. The pin104is coupled to the housing108and extends through the first joint line216A. The shoulder106is disposed outside of the elongated cavity208. In an embodiment, the pin104is rotated during the FSW process and contacts the edges402,404of the first flanges406,408at the first joint line216A. The friction between the pin104and the edges402,404heats the edges402,404and welds the two first flanges406,408of the work pieces212,214together at the first joint line216A. In an embodiment, the shoulder106is rotated during the FSW process, concurrently with the rotation of the pin104.

The pin104and the shoulder106may rotate relative to the housing108and the joint line216A, which are held stationary. For example, the housing108may not be physically able to rotate within the elongated cavity208. One or both of the side walls318,320of the housing108may contact corresponding side surfaces420,422of the elongated cavity208. For example, the side wall318may contact the side surface420of the first work piece212, and the side wall320may contact the side surface422of the second work piece214. In an embodiment, the side walls318,320are defined by the wear pads332. The wear pads332may be designed to slide along the corresponding side surfaces420,422with limited friction to reduce drag and/or low abrasion to avoid damaging the surface quality of the work pieces212,214. The wear pads332may be composed of nylon, high density plastic, or the like. The wear pads332may be replaceable.

In an embodiment, the flanges406,408of the work pieces212,214may be sandwiched between the shoulder106and the housing108during the FSW process. The housing108may include a support surface424that contacts respective inner (or lower) surfaces426,428of the flanges406,408. The surfaces426,428are inner surfaces because they face inside the elongated cavity208. The support surface424of the housing108may provide a base that prevents the deformable edges402,404along the joint line216A from drooping due to gravity and/or other forces. The support surface424may be smooth. The welded joint may conform to the smooth shape of the support surface424, resulting in a smooth surface finish along the inner surface of the welded joint.

The shoulder106may contact respective outer (or upper) surfaces430,432of the flanges406,408during the FSW process. For example, the shoulder106may be able to slide along the length of the pin104. The shoulder106may be biased towards the flanges406,408due to gravitational force. Alternatively, a biasing member, such as a spring, may exert a biasing force on the shoulder106towards the flanges406,408. The compressive forces provided by the shoulder106and the housing108may provide a desired shape and surface finish at the weld joint. A distal end434of the shoulder106may contact and slide along the outer surfaces430,432as the shoulder106rotates during the FSW process. The friction provided by the active rotation of the shoulder106may enhance the quality of the surface finish.

In an embodiment, the housing108includes at least one port440that extends into the interior of the housing108. The port440may be fluidly connected to one or more cooling channels that extend through the interior of the housing108. The cooling channels may extend proximate to the bearing assembly340shown inFIG.6. The cooling channels may be defined through the body326of the housing108. The port440may receive a coolant that absorbs heat from the housing108. The housing108includes a first port440A and a second port440B in the illustrated embodiment. Both ports440A,440B are disposed along a common end wall322of the housing108inFIG.7. The ports440A,440B are spaced apart along a width of the housing108. In alternative embodiments, the housing108may include a different number of ports and/or at least some of the ports may be disposed on different end walls of the housing108. In an embodiment, a respective fitting442is installed within each port440. The fitting442may be a quick connect fitting. The fitting442is configured to connect to a corresponding cooling line116(shown inFIG.1).

FIG.8is a perspective view of the FSW tool102shown without the shoulder106. The segment of the pin104that aligns with and contacts the work pieces212,214during the FSW process may have a non-uniform surface450. The non-uniform surface450may include undulations, ridges, serrations, and/or the like. Optionally, the non-uniform surface450may include smooth portions452and undulating portions454that alternate around a circumference of the pin104.

In an embodiment, the housing108includes a raised platform460that protrudes beyond an upper surface462of the top side316. The raised platform460defines the support surface424that contacts and supports the flanges406,408during the FSW process. The raised platform460may have an elliptical, anvil shape. The raised platform460may be centrally located along the top side316of the housing108, and is offset from a surrounding area of the top side316. The pin104extends through the raised platform460. In the illustrated embodiment, the raised platform460is a component of the upper plate330. In an alternative embodiment, the body326of the housing108may define the raised platform460. The support surface424on the raised platform460may be relatively planar. For example, the support surface424may be planar proximate to the pin104, and may taper or curve along radial edges of the raised platform460. In an alternative embodiment, the housing108does not include the raised platform460. For example, the support surface424may be defined by a central area of the top side316of the housing108that is flush with, or recessed below, a surrounding area of the top side316.

Optionally, the body326may define a dovetail interface470with the lower plate328of the housing108. The lower plate328may be assembled by sliding into the body326at the dovetail interface470. The fasteners334may secure the lower plate328in place.

FIG.9is a flow chart500of a welding method according to an embodiment. The welding method may be a friction stir welding process. The welding method may be performed using the FSW machine100shown inFIG.1. The method may be performed to weld two extruded, elongated work pieces together to form a unitary, one-piece weld structure. The weld structure may be relatively strong, stiff, and lightweight. The method optionally may include at least one additional step than shown, at least one fewer step than shown, and/or at least one different step than shown inFIG.9.

At step502, two elongated work pieces212,214are positioned in a fixture480to secure the work pieces212,214in fixed positions relative to one another. The work pieces212,214may be oriented in the fixture480such that edges402,404of first flanges406,408of the work pieces212,214oppose one another and define a joint line216. The joint line216may extend a length of the elongated work pieces212,214.

At step504, a FSW tool or tool102is loaded onto the two elongated work pieces212,214held in the fixture480. The FSW tool102may be mounted to a combined end segment of the two work pieces212,214at one of the ends. The FSW tool102may be loaded onto the work pieces212,214such that a pin104of the FSW tool102extends through the joint line216, a housing108of the FSW tool102is disposed along a first side of the joint line216, and a shoulder106of the FSW tool106is disposed along a second side of the joint line216opposite the first side. Optionally, the end of the of the work pieces212,214may include a pre-formed slot that aligns with the joint line216and accommodates the pin104. The pre-formed slot enables setting up the FSW tool102in a designated position prior to rotating the pin104.

In an embodiment, the two elongated work pieces212,214in the fixture480define an elongated cavity208that extends a length of the work pieces212,214. The cavity208may be defined by four walls with open ends. The joint line216extends through one of the four walls. Optionally, a second joint line216extends through another wall of the four walls. Loading the FSW tool102onto the two elongated work pieces at step504may include positioning the housing108within the elongated cavity208. The housing108of the FSW tool102may be sized relative to the cavity208such that corresponding side surfaces420,422of the work pieces212,214block rotation of the housing108within the cavity208.

At step506, a FSW process is performed using the FSW tool102. The FSW process may be performed at least in part by rotating the pin104and moving the FSW tool102along a length of the joint line216to form a welded joint. at the joint line216. The FSW process may be performed by positioning the housing108such that a support surface424of the housing108contacts respective inner surfaces426,428of the work pieces212,214surrounding the pin104and the joint line216. Performing the FSW process may include sandwiching opposing walls or flanges406,408of the work pieces212,214between a distal end434of the shoulder106and the support surface424of the housing108. The FSW process may also include rotating the shoulder106relative to the housing108such that both the pin104and the shoulder106are rotated. In an embodiment, the shoulder106may be rotated independently of the pin104. Optionally, the FSW process may include conveying a coolant to an interior of the housing108via a coolant line116that is connected to a port440of the housing108. The coolant may absorb and dissipate heat from the FSW tool102.

The work pieces212,214optionally may define both first and second joint lines216A,216B that extend parallel to one another along the length of the structure200. For example, the second joint line216B may be located along an opposite side of the cavity208from the first joint line216A. In an example, performing the FSW process may include forming a first welded joint along the first joint line216A during a first time period by moving the FSW tool102along the length of the structure200with the pin104extending through the first joint line216A. Then, the method500may include reorienting the FSW tool102relative to the work pieces212,214(after forming the first welded joint). The FSW tool102may be reoriented such that the pin104extends through the second joint line216B. For example, the FSW tool102may be flipped 180 degrees relative to the orientation of the work pieces212,214in the fixture480. The FSW process may include making a second pass of the FSW tool102along the length of the structure200to form a second welded joint at the second joint line216B.

In another example in which the two work pieces212,214define the two joint lines216A,216B, the method may include utilizing two different FSW tools102to each form one of the two welded joints. For example, a second FSW tool102may be loaded onto the work pieces212,214next to the first FSW tool102. This may include loading the two FSW tools102end-to-end within the elongated cavity208such that the second FSW tool trails the first FSW tool. The two FSW tools102may be copies or replicas of each other, such that the tools have the same components. The FSW machine100may be equipped with another set of spindles to simultaneously weld opposite joints.

In the illustrated embodiment shown inFIGS.7and9, the two FSW tools may be flipped 180 degrees relative to one another. The pin104of the first FSW tool extends through the first joint line216A, and the pin104of the second FSW tool extends through the second joint line216B. The FSW process may be performed by rotating the pin104of the first FSW tool, rotating the pin104of the second FSW tool, moving the first FSW tool along the length of the first joint line216A in a first direction to form the welded joint, and moving the second FSW tool along the length of the second joint line in the first direction to form a second welded joint. The first and second FSW tools may be concurrently moved with the second FSW tool trailing the first FSW tool.Clause 1: A friction stir welding (FSW) tool comprising:a pin configured to extend through a joint line between edges of two work pieces and to rotate to perform a FSW process that welds the two work pieces together at the joint line;a housing coupled to a distal end of the pin to enable rotation of the pin relative to the housing, the pin extending through a support surface of the housing, the support surface contacts respective inner surfaces of the work pieces during the FSW process; anda shoulder that surrounds the pin and is configured to be rotated during the FSW process, the shoulder contacting respective outer surfaces of the work pieces during the FSW process such that the work pieces are sandwiched between the shoulder and the support surface of the housing.Clause 2: The FSW tool of Clause 1, wherein the housing includes a top side and a raised platform that protrudes beyond an upper surface of the top side, wherein the support surface is disposed along the raised platform.Clause 3: The FSW tool of Clause 1 or Clause 2, wherein the shoulder is coaxial with the pin and configured to be rotated about the pin to perform the FSW process.Clause 4: The FSW tool of any of Clauses 1-3, wherein the distal end of the pin is coupled to a bearing assembly within an interior of the housing.Clause 5: The FSW tool of any of Clauses 1-4, wherein the housing includes first and second side walls configured to contact corresponding side surfaces of an elongated cavity defined by the two work pieces during the FSW process.Clause 6: The FSW tool of Clause 5, wherein the first and second side walls include wear pads that contact the corresponding side surfaces.Clause 7: The FSW tool of any of Clauses 1-6, wherein the housing is box-shaped and is sized to fit within an elongated cavity defined by the two work pieces.Clause 8: The FSW tool of any of Clauses 1-7, wherein the housing includes at least a first port extending through an end wall of the housing and configured to receive a coolant to dissipate heat.Clause 9: The FSW tool of Clause 8, further comprising a quick connect fitting installed within the first port and configured to connect to a cooling line that conveys the coolant.Clause 10: The FSW tool of any of Clauses 1-9, further comprising a first spindle connected to the pin and a second spindle connected to the shoulder, wherein the first spindle rotates the pin relative to the housing and the work pieces during the FSW process, and the second spindle rotates the shoulder relative to the housing and the work pieces during the FSW process.Clause 11: A welding method comprising:loading a FSW tool onto two elongated work pieces fixed in position relative to one another such that respective edges of the work pieces define a joint line therebetween, the FSW tool including a pin that extends through the joint line, a housing coupled to a distal end of the pin, and a shoulder that surrounds the pin, wherein the FSW tool is loaded such that the housing is disposed along a first side of the joint line and the shoulder is disposed along a second side of the joint line opposite the first side; andperforming a FSW process by at least rotating the pin and moving the FSW tool along a length of the joint line to form a welded joint.Clause 12: The welding method of Clause 11, wherein the edges of the work pieces are defined by opposing flanges of the work pieces, and performing the FSW process includes sandwiching the opposing flanges between a distal end of the shoulder and a support surface of the housing.Clause 13: The welding method of Clause 11 or Clause 12, wherein performing the FSW process includes rotating the shoulder relative to the housing.Clause 14: The welding method of any of Clauses 11-13, wherein performing the FSW process includes positioning the housing such that a support surface of the housing contacts respective inner surfaces of the work pieces surrounding the pin and the joint line.Clause 15: The welding method of any of Clauses 11-14, wherein loading the FSW tool onto the two elongated work pieces comprises positioning the housing within a cavity defined by the work pieces that extends the length of the joint line.Clause 16: The welding method of Clause 15, wherein the housing of the FSW tool is sized relative to the cavity such that corresponding side surfaces of the work pieces block rotation of the housing within the cavity.Clause 17: The welding method of any of Clauses 11-16, further comprising conveying a coolant to an interior of the housing while performing the FSW process, the coolant conveyed via a coolant line that is connected to a port of the housing.Clause 18: The welding method of any of Clauses 11-17, wherein the joint line is a first joint line, the welded joint is a first welded joint, and the work pieces define a second joint line therebetween that is parallel to and along an opposite side of a cavity from the first joint line, wherein performing the FSW process includes reorienting the FSW tool relative to the work pieces after forming the first welded joint and moving the FSW tool along the length of the second joint line to form a second welded joint.Clause 19: The welding method of any of Clauses 11-18, wherein the FSW tool is a first FSW tool, the joint line is a first joint line, the welded joint is a first welded joint, and the work pieces define a second joint line therebetween that is parallel to and along an opposite side of a cavity from the first joint line, the method further comprising:loading the second FSW tool onto the work pieces next to the first FSW tool such that a pin of the second FSW tool extends through the second joint line,wherein performing the FSW process comprises rotating the pin of the first FSW tool, rotating the pin of the second FSW tool, moving the first FSW tool along the length of the first joint line in a first direction to form the welded joint, and moving the second FSW tool along the length of the second joint line in the first direction to form a second welded joint, wherein the first and second FSW tools are concurrently moved and the second FSW tool trails the first FSW tool.Clause 20: A welding assembly comprising:a structure defined by two elongated work pieces fixed in place relative to each other, the structure including a joint line defined between respective edges of the two elongated work pieces, the structure including a cavity that extends a length of the joint line; anda friction stir welding (FSW) tool comprising:a housing disposed within the cavity;a pin extending through the joint line and coupled to the housing, the pin configured to rotate relative to the housing and the joint line to perform a FSW process that welds the two elongated work pieces together at the joint line; anda shoulder disposed outside of the cavity and surrounding the pin, the shoulder configured to rotate relative to the housing and the joint line during the FSW process.

While various spatial and direction terms such as top, bottom, lower, mid, lateral, horizontal, vertical, front and the like can be used to describe embodiments of the present disclosure, it is understood that such terms are merely used with respect to the orientations shown in the drawings. The orientations can be inverted, rotated, or otherwise changed, such that an upper portion is a lower portion, and vice versa, horizontal becomes vertical, and the like.

As used herein, a structure, limitation, or element that is “configured to” perform a task or operation is particularly structurally formed, constructed, or adapted in a manner corresponding to the task or operation. For purposes of clarity and the avoidance of doubt, an object that is merely capable of being modified to perform the task or operation is not “configured to” perform the task or operation as used herein.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) can be used in combination with each other. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the various embodiments of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments of the disclosure, the embodiments are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the various embodiments of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims and the detailed description herein, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.

This written description uses examples to disclose the various embodiments of the disclosure, including the best mode, and also to enable any person skilled in the art to practice the various embodiments of the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the various embodiments of the disclosure is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if the examples have structural elements that do not differ from the literal language of the claims, or if the examples include equivalent structural elements with insubstantial differences from the literal language of the claims.