Tool Rotation Direction Research Articles

Development of Friction Stir Incremental Forming Process Using Penetrating Tool

Abstract In order to form sheet metals into concave-convex shape without using special machines or dies, a new forming method called friction stir incremental forming using penetrating tool was proposed. A forming tool called a penetrating tool was originally developed and this tool was composed of two dome shape tools, which located between an upper tool and a lower tool symmetrically and were jointed of a screw. Pure aluminum JIS: A1050-O sheets having a thickness of 2 mm were used for workpiece. Sheets were formed into a truncated cone shape. Concave, convex and concave-convex shapes were formed successfully by the proposed method. The effect of tool rotation direction, clockwise and counter clockwise, was also investigated.

Excellent Formability of Light Metals Sheets by Friction Stir Incremental Forming

The results about friction stir incremental forming of light metals sheets from the beginning of development to the latest in the author’s laboratory are introduced. Comparison of formability by the conventional single point incremental sheet metal forming and friction stir incremental forming for magnesium alloys, aluminum alloys and titanium sheets were introduced. Effect of tool rotation direction, multistage forming and double side forming are also introduced.

Parametric Influence of Friction Stir Welding on Cast Al6061/20%SiC/2%MoS<sub>2</sub> MMC Mechanical Properties

In this work, effect of tool speed and direction of tool rotation of friction stir welding (FSW) process on the cast MMC is analyzed. Aluminum 6061 alloy reinforced with 20% silicon carbide particles added with 2% molybdenum disulphate is prepared by die casting process. Macro and micro-structural analysis is performed to study the size and shape of the constituents, to discover the defects associated with stir welding and quality of weld. Micro-hardness observations are carried out on the parent metal, FSW zone and heat affected zone. It is observed that FSW with high speeds develops higher hardness and most of the higher hardness value occurs in in the order of FSW welding zone, center zone and heat affected zone, and also hardness value of clockwise tool rotation is greater than anti-clockwise tool rotation.

In-situ material flow pattern around probe during friction stir welding of austenitic stainless steel

The probe route as well as the material flow around the keyhole during weld termination were tracked and used to determine the probe position just prior to weld termination. This approach enables analysis of in-situ microstructure distribution and the nature of material flow during friction stir welding (FSW). A FSW flow model was established. During steady state FSW, the material at the advancing side (AS) recrystallized rapidly when it was swept by the hot rotating probe. The recrystallized grains were driven to rotate around the probe along the tool rotation direction, forming the material flow zone (MFZ). As the base material approached the probe, it was compressed initially, forming a compression zone (CPZ) mainly consisted of coarse deformed grains. When the coarse deformed grain in CPZ collided with the hot material in the MFZ, it recrystallized and added into the MFZ, thickening the MFZ ahead of the probe. During FSW, the material intersecting the path of probe was displaced to rotate around the probe and then deposited behind the probe at roughly the same transverse position as its initial position.

Fabrication of metal-matrix AL7075T651/TiN nano composite employing friction stir process

Friction stir processing is a novel material fabrication technique. This study was undertaken in order to investigate a suitable set of friction stir processing parameters to form AL7075T651/TiN nano composite. A number of samples were produced by varying the process parameters, namely, tool-pin geometry, number of passes and the direction of tool rotation. The pin geometries employed include triangular, square and threaded taper; the passes were varied over two levels (i.e. 2 and 4) and the tool rotation was changed as clockwise and counter clockwise between the successive passes. The effect of these variations on the composite was quantified through several microstructural and mechanical tests. The increase in the number of passes was observed to improve various characteristics of the composite (i.e. distribution of TiN particles, grain refinement and mechanical properties). The effect of tool geometry, however, was associated with the choice of the number of passes. The change in the direction of tool rotation between the consecutive passes was witnessed to improve the distribution of TiN particles. From the X-ray diffraction analysis of the samples, the formation of several new phases was detected. These were found to have effect on the mechanical properties of the composite. A good trade-off among various properties of the composite (i.e. hardness, tensile strength and ductility) was realized when the friction stir processing was performed using square tool and employing four passes with simultaneously changing the direction of tool rotation between the successive passes. This study is the first report on the fabrication of AL7075T651/TiN nano composite through friction stir processing route.

Effect of Cutting Conditions on Tool Wear in Driven Rotary Cutting of Maraging Steel

In this paper, driven rotary cutting of maraging steel was carried out and the influence on tool wear of difference cutting conditions was investigated. As cutting conditions, different coolant conditions, cutting speeds, circumferential velocity ratios, tool inclination angles, tool rotation directions and normal rake angles were tested. We found that as the coolant quantity decreased and cutting speed increased, the width of flank wear increased. It was also found that the circumferential velocity ratio, tool inclination angle, tool rotation direction and normal rake angle have optimal conditions that decrease wear. Optimal conditions were chosen, and a tool life test was carried out. As a result, driven rotary cutting was achieved with 11 or more times the tool life of conventional turning.

Effect of Difference of Tool Rotation Direction on Forming Limit in Friction Stir Incremental Forming

An effect of tool rotation direction on forming limit in friction stir incremental forming was studied. A 3-axes NC milling machine and a hemispherical tool which with a diameter of 6 mm made of high speed steel was used for forming. The thickness of commercial A5052-H34 aluminum sheet was 0.5 mm. The forming tool was moved from the outside to inside in a pitch of 0.5 mm spirally, and the sheets were formed into frustum of pyramid shape. Formability evaluated by minimum wall angle of the pyramid was investigated by changing a tool rotation rate, tool feed rate and tool path direction. When the tool paths were clockwise and counter clockwise, they were defined to “advancing direction” and “retreating direction” as well as in friction stir welding, respectively. From the experimental results, forming limits by both rotation directions of advancing and retreating were almost the same, however, the range of formable working conditions in advancing direction was slightly wider than that in retreating direction. Evaluating the forming limits in relative velocity between the tool surface and the sheet, no difference of forming limit was obtained between forming in advancing direction and retreating directions.

Effect of weld curvature radius and tool rotation direction on joint microstructure in friction stir welding casting alloys

Curved welds were designed and the effects of the weld curvature radius and tool rotation direction on the microstructure of friction stir welded cast aluminum alloy joints were investigated. Results show that both the weld curvature radius and tool rotation direction have a significant influence on the microstructure of the curved joints during FSW. With decreasing weld curvature radius, the size of the tunnel defect is reduces and the proportion of fine Si particles in the stir zone increases. Si particles are finer and denser in the retreating side (RS) than that in the advancing side (AS) when both the welding direction and tool rotation direction are anticlockwise. However, when the welding direction is anticlockwise while the tool rotates clockwise, the proportions of fine Si particles decrease compared to the former situation. Furthermore, the tunnel defect is more likely to be present in the AS in the former situation.

925 摩擦撹拌インクリメンタルフォーミングにおける工具と板材の相対速度が成形性に及ぼす影響

925 摩擦撹拌インクリメンタルフォーミングにおける工具と板材の相対速度が成形性に及ぼす影響

J041043 摩擦撹拌インクリメンタルフォーミングにおける工具回転方向が成形性に及ぼす影響

Effect of tool rotation direction on forming limit in friction stir incremental forming was studied. Commercial A5052 aluminum alloy sheet with a thickness of 0.5 mm was employed for specimens. Forming limits by both rotation directions in advancing and retreating ones were same, however, the range of formable working condition by advancing direction was smaller than that by retreating direction. Appearance of part surface formed by advancing direction was more beautiful and smoother than that formed by retreating direction.

A Review of FSW Research on Dissimilar Metal and Alloy Systems

This review summarizes friction-stir welding (FSW) research over a period of a decade and a half, involving 18 different same materials FSW reference systems, and the FSW of 25 different, dissimilar materials systems. These are summarized in tables. The FSW of dissimilar materials systems is distinguished from same materials systems FSW by the formation of complex, intercalated vortex, and related flow patterns. These intercalated, lamellar-like patterns represent solid-state flow by dynamic recrystallization (DRX) which facilitates unrecrystallized, block flow in the DRX regime. A detailed characterization of representative systems involving optical and transmission electron microscopy is also presented. Residual microindentation hardness or other hardness measured across the weld face provides comparative performance signatures for the same material FSW systems in contrast to the dissimilar FSW systems. Hardness fluctuations or complex spikes occurring in the dissimilar systems are skewed from the weld centerline and are shifted when the tool rotation direction changes or the advancing side is reversed.

Textures in Single-Crystal Aluminum Friction Stir Spot Welds

The present article examines the textural features produced during friction stir spot welding of single-crystal aluminum sheet. The crystal has the {111} plane perpendicular to the normal direction (ND) of the sheet, and the $$ \left\langle { 1 10} \right\rangle $$ direction parallel to the growth direction (GD). Friction stir spot welding was carried out using a rotation speed of 1500 rpm and a dwell time of 2 seconds, and completed spot welds were characterized using a combination of optical microscopy and electron backscatter diffraction (EBSD). The EBSD measurements indicate there are no significant changes in orientation in locations more than 840 μm from the stir-zone extremity. The orientation distribution in the thermomechanically-affected zone (TMAZ) region conformed with the {110}⊥ND orientation within 580 μm of the stir-zone extremity. In the location immediately adjacent to the stir-zone extremity, there was a deviation from the {110}//ND orientation due to a combination of compressive loading perpendicular to the stir-zone boundary and shear loading in the direction of tool rotation. It is suggested a {111}⊥ND texture in the stir zone is associated with material flow imposed by the thread on the rotating pin.