3.5 Workpiece and Tool Material
The workpiece material considered for the present experimental work is the commercially available 1100 series aluminium alloy
reason behind the selection of the softer grade Al series is its popular use for general sheet metal work in chemical process plant equipment, food industry containers etc., availability,
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(a) (b) Figure 3.6 (a) Detail drawing and (b) image of support plate
Assembly
The complete assembly of the developed fixture is shown in
assembled together with their relative positioning. It is designed in such a all the features required to carry out FSW operations
facilitated. The developed fixture was found very effective for supporting and clamping the
Figure 3.7 Complete fixture assembly
Workpiece and Tool Material
The workpiece material considered for the present experimental work is the commercially available 1100 series aluminium alloy without any heat treatment. The main reason behind the selection of the softer grade Al series is its popular use for general sheet metal work in chemical process plant equipment, food industry containers etc., availability, Chapter 3
(b) (a) Detail drawing and (b) image of support plate
developed fixture is shown in Fig. 3.7. All the parts of assembled together with their relative positioning. It is designed in such a s in milling machine are for supporting and clamping the
The workpiece material considered for the present experimental work is the without any heat treatment. The main reason behind the selection of the softer grade Al series is its popular use for general sheet metal work in chemical process plant equipment, food industry containers etc., availability,
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Experimental Setup
78
and low cost. The rolled plates were cut and machined into rectangular pieces of 200×100×6 mm for joining purpose. Welding was carried out in butt joint configuration using FSW process. EDX (Energy-dispersive X-ray spectroscopy) was carried out to find out the composition of the aluminum alloy and the results are shown in Fig. 3.8. The chemical composition and mechanical properties of the plate are given in Tables 3.1 and 3.2, respectively.
Figure 3.8 EDX spectrum of workpiece material Table 3.1 Chemical Composition of Base Material
Elements Cu Si Fe Al
Weight (%) 0.05 0.2 0.1 Balance
Table 3.2 Mechanical Properties of Base Material Ultimate tensile
strength (MPa) Yield strength (MPa) % Elongation
153.05 84.93 33.04
The tool material should be such that it can withstand the vertical pressure and torque applied to it. The FSW tool should not wear out easily. Hence choosing an appropriate tool material is important for FSW application. In this work, stainless steel (Grade-310) is used as tool material because of its excellent high temperature properties with good ductility. A vertical milling machine was used to carry out the horizontal FSW experiments. The specification of the milling machine used is; Spindle speed: 12 steps [50-1500 rpm], Table feed rate: 8 steps [22-555 mm/min], Main motor power: 5.5 kW, Feed motor power: 0.75
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kW. The tool was mounted using a suitable collate. The tool rotation speed and translational speed of the bed were set prior to each run of welding. Before welding the edge mismatch of the plates was checked. In order to avoid mismatch, the edges of all the workpieces are machined. Some minor cleaning of the joining surfaces by fine grade emery paper has also been done to remove atmospheric contaminations. The parameters used in the present work are shown in Table 3.3.
Table 3.3 Parameter Descriptions with Units Used
Parameters Unit Description
Plunge depth (PD) mm Distance moved by the shoulder from workpiece surface along the tool axis.
Tool rotational speed (RPM)
rev/min Revolutions per minute of machine spindle.
Welding speed (WS) mm/min Speed of tool advancing through the workpiece.
Tool geometry (TG) - Straight cylindrical (SC), Tapered cylindrical (TC), Square (SQ), Threaded (THRD).
Shoulder diameter (SD) mm Diameter of the tool shoulder.
Pin diameter (PnD) mm Diameter of the tool pin.
Tool pin length (TPL) mm Distance between inner shoulder surface and tip of pin along tool axis.
Dwell time (DT) second Time between plunge sequence and weld traverse sequence.
3.6 Tool Fabrication
Welding tools were prepared from either 42 mm or 32 mm round stainless steel (Grade- 310) bar. Different tool geometries that were considered in the present work are straight cylindrical (SC), tapered cylindrical (TC), square (SQ) and threaded tool (THRD). The fabricated 32 numbers of tools having different shape and dimensions are shown in Fig. 3.9 (a-d). Initially all the 8 numbers of straight cylindrical tools and 8 numbers of tapered cylindrical tools were prepared using lathe machine. For preparing square and threaded tools first the tool pins were made in a straight cylindrical shape using lathe machine. Then squares of appropriate diagonal were prepared using milling machine and right handed threads having a pitch of 1mm were prepared using lathe machine.
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Experimental Setup
(a)
(c)
Figure 3.9 Fabricated tools (a) SC (b) TC (c) SQ and (d) THRD
3.7 Temperature Measurement During Welding
For temperature measurement an Infra Red (IR) camera was implemented. It is having a spectral range of 7.5 to 14 µm, temperature measuring range (
resolution at 30°C better than 0.05 K, measurement accuracy ± 1.5 K (0
and > 100°C), emissivity adjustable from 0.1 to 1.0, in increments of 0.01 (Make:
INFRATEC, Model: VarioCAM
appropriate location to capture the thermal image. The complete experimental setup with camera is shown in Fig. 3.10(a). For each experiment the straight lines as shown in
are marked (in the advancing side) prior to the welding which is exactly at half the distance of the tool shoulder diameter from the welding line. Then the te
the point which is at a distance of 120 mm away from the starting edge of the 200 mm long
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(a) (b)
(c) (d) Fabricated tools (a) SC (b) TC (c) SQ and (d) THRD