Effect Of Tool Shoulder Diameter Research Articles

An experimental method for choosing the tool pin profile and shoulder size to join dissimilar aluminum alloys AA7075-T651 and AA6061-T6 joints

Many military and light weight aircraft designs call for joints between two different grades of aluminium alloy. This present study looked at the effect of tool shoulder diameter and tool pin profile on the tensile strength properties of dissimilar aluminium alloy AA6061-T6 and AA7075-T651 joints created by friction stir welding. The joints were fabricated utilizing three distinct tool shoulder diameters 15 mm, 20 mm and 25 mm along with two distinct tool pin profiles namely taper and square. The microstructure and microhardness of weld stir zone (WSZ) were examined and linked with the strength parameters of the joints. Adequate frictional heat generation from 20 mm shoulder diameter and pulsating stirring action of square pin revealed the formation of very fine grains in the weld nugget zone (WNZ). Due to enhanced material flow and the production of a defect-free stir zone, the joint created using a tool with a 20 mm shoulder diameter and square pin profile had the maximum hardness of 117 HV and the highest tensile strength of 284 MPa. The ductile mechanism of fracture is revealed by the presence of fine dimples accumulating in the tensile fractured surface of the joint fabricated by 20 mm tool shoulder diameter and square pin.

Electrochemical behaviour of friction stir welded joints: Effect of tool shoulder diameter

In the present research work, the effect of shoulder diameter on the corrosion rate of stir zones (SZs) of dissimilar joints exposed to 3.5 M NaCl solution fabricated via friction stir welding (FSW) was studied in detail. In FSW, the tool shoulder diameter as one of the important process parameters significantly affects frictional heat input and material flow leading to the heterogeneous distribution of second phase particles (precipitates) that alters the electrochemical behaviour of FSWed joints. The influence of shoulder diameter on corrosion rate was analyzed via macro and microstructural characterization and open circuit potentiodynamic testing. The surface morphology and microstructural analysis of specimens reveal the occurrence of both pitting and intergranular corrosion (IGC) in base materials and SZs of welded specimens. Among the welded specimens, the SZ of weld I fabricated under shoulder size of 18 mm revealed the lower corrosion resistance. The potentiodynamic test revealed that weld I having very fine grains as compared to other joints exhibits the highest current density and corrosion rate.

Effect of Tool Shoulder Diameter on the Surface Hardness of Aluminum-Molybdenum Surface Composites Developed by Single and Double Groove Friction Stir Processing

Molybdenum (Mo), possessing higher hardness compared to aluminum (Al), is used for the surface hardness improvement in Al 1050 alloy. Al-Mo surface composites are developed using friction stir processing with different tool shoulder diameters. Single groove composite (SGC) and double groove composite (DGC) samples are processed with 22-, 20-, and 18-mm shoulder diameter tools to study the effect of tool shoulder diameter and Mo content on the surface hardness of Al-Mo surface composites. Microhardness increased from 26 to 51 Hv on the top surface and 52 Hv on the cross section surface, in 18 DGC. The surface hardness of the composite samples increased with decrease in tool shoulder diameter due to the combined effect of grain refinement and Mo reinforcement particles. Unprocessed Al 1050 base alloy possessed an average grain size of ~ 99 µm. The grain size in the processed samples reduced with decrease in tool shoulder diameter. Surface composites processed with 22-, 20-, and 18-mm tools exhibited an average grain size of ~ 23, ~ 22, and ~ 21 µm, respectively. The amount of Mo particles incorporated in the composite material increased with decrease in tool shoulder diameter. Microstructural analysis confirmed that the FSP groove method incorporated about ~ 8 wt pct Mo in 22 SGC and ~ 12 wt pct in 22 DGC, respectively. The amount of Mo particles in 20 SGC and 20 DGC is ~ 17 wt pct and ~ 22 wt pct, respectively, whereas 18 SGC and 18 DGC possessed ~ 27 wt pct and ~ 31 wt pct Mo particles. Mechanical shearing through severe plastic deformation during the friction stir processing reduced the average Mo particle size in the surface composites. Molybdenum is distributed in its elemental form in the Al-Mo surface composites without any intermetallic formation.

Effect of D/TP ratio on stir zone characteristics of friction stir-welded high-strength low-alloy steel plates

In this study, the effect of tool shoulder diameter (D) to the plate thickness (Tp) ratio on tensile and impact toughness properties of friction stir-welded naval grade high-strength low-alloy steel was investigated. A naval grade high-strength low-alloy steel of 5 mm thick plates was welded with tool rotational speed of 600 r/min and welding speed of 30 mm/min using tungsten-based alloy tools having D/Tp ratio varying from 4 to 6. Microstructural characteristics of the weld joints were analyzed using optical microscopy and scanning electron microscopy with energy dispersive spectroscopy along with the evaluation of tensile properties. From this investigation, it was found that the joint fabricated using a D/Tp ratio of 5 (25 mm shoulder diameter) exhibited superior mechanical properties compared to other joints.

Effect of Tool Shoulder Diameter on Stir Zone Characteristics of Friction Stir Welded HSLA Steel Joints

In this study, the effect of tool shoulder diameter (primary heat generating source) to the plate thickness ratio on tensile and impact toughness properties of friction stir welded high strength low alloy (HSLA) steel was investigated. A naval grade HSLA steel of 5 mm thick plates were welded with tool rotational speed of 600 rpm and welding speed of 30 mm/min using five tungsten based alloy tools having shoulder diameter varying from 20 to 30 mm. Microstructural characteristics of the weld joints were analyzed using optical microscopy along with the evaluation of tensile properties. From this investigation, it was found that the joint fabricated using a tool shoulder diameter of 25 mm (5 times the plate thickness) exhibited superior mechanical properties compared to other joints.

Effect of Tool Shoulder Diameter to Plate Thickness Ratio on Mechanical Properties and Nugget Zone Characteristics During FSW of Dissimilar Mg Alloys

During friction stir welding (FSW), frictional heat is produced in the region between the tool shoulder and base materials due to the movement of the rotating tool along the line of joint. In this paper, an experimental investigation was made to understand the influence of the tool shoulder diameter (primary source of heat generation) on the microstructural characteristics and mechanical properties of dissimilar Mg alloys namely AZ80A and AZ91C. From the experimental results, it was observed that the use of FSW tool having 17.5 mm shoulder diameter (3.5 times the plate thickness) produced defect free sound joints with superior mechanical properties compared to its counterparts. Moreover, the uniformly distributed fine sized grains of nugget zone also contributed to the sound quality joints. From this investigation, it was understood that higher heat input is essential for enabling the required mixing of materials during FSW of dissimilar Mg alloys.

Effect of Heat Input on AA5052 Friction Stir Welds Characteristics

Friction Stir Welding (FSW) is a relatively novel solid state welding process that strong enhanced the welding of aluminum alloys for structural applications. In this process, the heat necessary for the required plastic flow of material is produced at the interfase tool-work piece, being affected by factors such as rotational speed, axial load and tool shoulder diameter, among others. The objective of this work was to study the effect of tool shoulder diameter on heat input during FSW of AA5052-H32 alloy and the resulting characteristics of the produced welded joints. Tools of 10, 12, 14 and 16mm shoulder diameter were constructed and used to butt weld plates of 3mm thick of AA5052-H32 aluminum alloy. Welds were made with 514rpm of rotational speed and 98mm/min of welding speed. Thermal cycles were acquired during welding using thermocouples. Macrostructural characterization and Vickers microhardness profiles were done on each welded sample. It was observed an increase in power with shoulder diameter, as well as a lower level of defects in the stirred zone, related with an improved plastic flow. Hardness also decreased with tool diameter, due to a higher thermal effect on the microstructure.

Effect of Tool Shoulder Diameter During Friction Stir Processing of AZ31B Alloy Sheets of various Thicknesses

Friction-stir processing (FSP) is an emerging severe plastic deformation technology that is based on friction stir welding (FSW). In FSP, the tool plays a very important role in producing a defect free processed zone. The shoulder of the tool, which is the main source of heat generation, is typically either flat or tapered in shape. The typical shape of the shoulder aids in material consolidation during processing by forcing the softened material to be retained in the processed zone, as the tool traverses along the length of the work piece. The pin also plays a very important role, in refining the grain size along the through-thickness of the work piece. In this work, high carbon steel of and AZ31B magnesium alloy (6mm & 1.5mm thick) was chosen as a tool material and work piece material respectively. The tool shoulder diameter of 18mm and 24mm were chosen to friction stir process the work piece material in a single pass. The possibility of Increase in the tool shoulder diameter beyond 18mm but less than 24mm, a defect free processed zone was observed for variation in the process parameters in 6mm thick plate. Also as the thickness of work piece is reduced, the defects in the friction stir processed zone of 1.5mm thick plate is completely eliminated. A fine equiaxed grain of average grain size less than 10μm were during friction stir processing, thus creating the material to exhibit superplasticity.

The Behavior of Friction Stir Welded (FSW) Sheets of AA6061-T6 During in-plane Stretching Test

The present work investigates the effect of tool shoulder diameter, plunge depth, tool rotation speed and welding speed on the load- extension behaviour during in-plane stretching of FSW blanks made of Al 6061 alloy. In-plane stretching test was performed on Instron machine similar to tensile test. The data were taken from the machine and plotted the graphs for each parameter. It is found from the present work that the maximum load has increased with decrease in shoulder diameter, increase in welding speed and tool rotational speed. The load required is almost same for two different plunge depths. The extension has increased with increase in shoulder diameter, plunge depth, welding speed and tool rotational speed, while the base metal has maximum load and lesser extension. The failure pattern is same for un-welded and welded blanks, except the failure initiation.

EFFECT OF TOOL SHOULDER DIAMETER ON THE MECHANICAL PROPERTIES OF 1200 ALUMINUM FRICTION STIR SPOT WELDING

A friction stir spot welding (FSSW) process is an emerging solid state joining process in which the material that is being welded does not melt. In this investigation an attempt has been made to understand the effect of tool shoulder diameter on the mechanical properties of the joint. For this purpose four welding tools diameter (10,13, 16 and 19) mm at constant preheating time and plunging time were used to carryout welding process. Effect of tool diameter on mechanical properties of welded joints was investigated using shear stress test and Microhardness of joint which welded was studied. Based on the stir welding experiments conducted in this study the results show that aluminum alloy (1200) can be welded using (FSSW) process with maximum welding efficiency (80%) shear strength using tool diameter(19mm) with rotation speed (900rpm).

Effect of Tool Shoulder Diameter on Mechanical Properties of Friction Stir Spot Welded Joints

The effect of tool geometry on microstructure and tensile shear strength in friction stir spot welds of 6061 aluminium alloy sheets was studied. Tools with three different shoulder diameters were evaluated. The shape parameters dn and tu were defined from the weld structure observed on the cross section of the weld centre, which represent the actual nugget size and the thickness of the upper sheet under tool shoulder circumference, respectively. These parameters and the shape of the boundary between the upper and lower sheets varied depending on shoulder diameter, tool rotational speed and tool holding time. The tensile shear strengths at the fixed tool rotational speed were dependent on tool holding time and shoulder diameter. Two fracture modes were recognized under tensile shear loading at the shoulder diameters of 10 and 15 mm. The dependence of static strength on shoulder diameter was discussed based on the shape parameters and fracture modes.

526 摩擦撹拌スポット接合継手の強度特性に与える接合ツールショルダー径の影響(GS.B 接着・接合)

526 摩擦撹拌スポット接合継手の強度特性に与える接合ツールショルダー径の影響(GS.B 接着・接合)