4 An Application from a Defect—A Friction …
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clearance, C between the shoulder and the workpiece surface. For the conventional
FSC process, proper C must be maintained for deposition of the material that is
extruded out and flows upward during the process. However, in another variant, i.e.,
the new FSC technique, it is seen that the channel can be formed at zero value of C
also [50].
The second step, i.e., dwelling of the pin is also similar to FSW. But unlike the
insertion of shoulder in FSW, since in FSC only the pin is inserted into a certain
depth, therefore, in FSC only the pin dwells in the same position to generate heat.
Thus, the heat generation, and as a consequence, the amount of material that gets
softened in this step, is low as compared to that of FSW.
In the third step, the pin then traverses with a given value of v. But unlike FSW,
the tool traverses with extracting the material along its length. The extraction is
caused because of ω, and the thread orientation of the pin. The extracted material
accumulates in the gap or clearance provided and seals the channel roof along the
length. The value of v given in FSC is higher than that in FSW so that low heat
generation conditions can be fulfilled.
The last stage i.e., the retracting of the pin is similar to that of the last step of
FSW. Here the pin is pulled out at the end of the channeling line leaving a keyhole
at the end.
4.5.1 FSC Principle
The main features of FSC that are different from FSW are as follows:
• The flow of material in FSC is upward and towards the shoulder from the base of
the plate. It is obtained by rotating a profiled tool (mainly threaded).
• A suitable gap, i.e., a proper value of C is maintained throughout the process so
that the material that comes out of the base of the material can be deposited in
this gap itself. The geometry, dimension, and continuity of the channel can be
adjusted by C.
The clockwise rotation of a right-hand threaded (RHT) tool or counterclockwise
rotation of a left-hand threaded (LHT) tool produces a force that acts in the upward
direction during FSC. The upward force shears the plasticized material from the
bottom and around the pin. This material is then deposited in the gap. Unlike FSW,
the absence of PD of the shoulder in FSC results in lower heat generation. The low
heat generation is necessary for the formation of a wormhole defect.
4.5.2 FSC Parameters and Their Influence
The primary parameters that influence the FSC process are also similar to that of FSW
process (ω, v, PD). With the most common influential parameters in FSW, two other
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clearance, C between the shoulder and the workpiece surface. For the conventional
FSC process, proper C must be maintained for deposition of the material that is
extruded out and flows upward during the process. However, in another variant, i.e.,
the new FSC technique, it is seen that the channel can be formed at zero value of C
also [50].
The second step, i.e., dwelling of the pin is also similar to FSW. But unlike the
insertion of shoulder in FSW, since in FSC only the pin is inserted into a certain
depth, therefore, in FSC only the pin dwells in the same position to generate heat.
Thus, the heat generation, and as a consequence, the amount of material that gets
softened in this step, is low as compared to that of FSW.
In the third step, the pin then traverses with a given value of v. But unlike FSW,
the tool traverses with extracting the material along its length. The extraction is
caused because of ω, and the thread orientation of the pin. The extracted material
accumulates in the gap or clearance provided and seals the channel roof along the
length. The value of v given in FSC is higher than that in FSW so that low heat
generation conditions can be fulfilled.
The last stage i.e., the retracting of the pin is similar to that of the last step of
FSW. Here the pin is pulled out at the end of the channeling line leaving a keyhole
at the end.
4.5.1 FSC Principle
The main features of FSC that are different from FSW are as follows:
• The flow of material in FSC is upward and towards the shoulder from the base of
the plate. It is obtained by rotating a profiled tool (mainly threaded).
• A suitable gap, i.e., a proper value of C is maintained throughout the process so
that the material that comes out of the base of the material can be deposited in
this gap itself. The geometry, dimension, and continuity of the channel can be
adjusted by C.
The clockwise rotation of a right-hand threaded (RHT) tool or counterclockwise
rotation of a left-hand threaded (LHT) tool produces a force that acts in the upward
direction during FSC. The upward force shears the plasticized material from the
bottom and around the pin. This material is then deposited in the gap. Unlike FSW,
the absence of PD of the shoulder in FSC results in lower heat generation. The low
heat generation is necessary for the formation of a wormhole defect.
4.5.2 FSC Parameters and Their Influence
The primary parameters that influence the FSC process are also similar to that of FSW
process (ω, v, PD). With the most common influential parameters in FSW, two other