Pin Shape Research Articles

Impact of Flat-Surfaced Pins on Material Flow and Particle Distribution in Friction Stir Processing: A CEL Method Analysis

Abstract This study investigates the impact of Flat-Surfaced Pin geometry on temperature, strain, particle distribution, and material flow during Friction Stir Processing (FSP) using a Coupled Eulerian-Lagrangian (CEL) formulation. Various models incorporating different pin shapes—cylindrical, square, and hexagonal—were developed for this purpose. To investigate material flow during the FSP, Tracer particles were employed as a methodological tool. A comparison between experimental and numerical results concerning the distribution of reinforcing particles in the base metal reveals a strong correlation, highlighting the model's effectiveness in accurately predicting material flow patterns. The findings indicate that the circular tool was less effective in achieving a uniform distribution of particles, with a significant accumulation observed on the retreating side. In contrast, both square and hexagonal tools demonstrated improved performance regarding particle distribution. Quantitative measurements show that the areas occupied by the reinforcing particles are 14.3 mm² for the circular pin, 34.4 mm² for the square pin, and 37.9 mm² for the hexagonal pin. This variation can be attributed to the design of the pin profiles, as the flat surfaces facilitate a pulsating effect that enhances material flow. Moreover, in samples processed with square and hexagonal pins, particles located near the upper surface of the plate tend to rotate with the pin, subsequently stretching toward the advancing side. Finally, the square and hexagonal tools exhibited higher average hardness values of 68.88 HV and 66.84 HV, respectively, compared to the circular tool, which yielded an average hardness of 57.17 HV.

Moulded-Pulp Packaging: A Straightforward Method for Quickly Designing, Manufacturing and Testing Complex Shapes for Crash Protection Pads

Moulded-pulp packaging stands poised to replace traditional polystyrene packaging due to its eco-friendly nature and recyclability. However, optimizing the protective pins within moulded-pulp packaging has been a challenge, hindering its widespread adoption. This paper presents an innovative approach to swiftly and cost-effectively optimize pin shapes, which is crucial for enhancing impact resistance. We hereby propose a simple try and error pin optimization methodology by utilizing an hand-moulded pulp recipe and PLA 3D-printed moulds to rapidly craft tailored cardboard pins. The validation of the material fabrication was carried out with static characterization and the classification of the homemade moulded-pulp pins with impact testing analysis. This exploratory project demonstrates the feasibility of this approach, laying the foundation for future advancements in moulded-pulp packaging design.

Impact of tool geometry and friction stir welding parameters on AZ31 magnesium alloy weldment wear behaviour and process optimization

This study investigates the impact of friction-stir welding (FSW) tool pin shape (TPS) and processing variables, viz., rotation speed (RS), axial load (AL), and traverse speed (TS), on weld beads’ wear characteristics as per ASTM G99 standard. Wear rate (WR), friction force (FF), and coefficient of friction (CoF) are analyzed based on Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). FSW performed with a hexagonal TPS provides a better material flow between the plates, influencing the joint’s strength and improving the wear resistance of weldments. Higher RS leads to high material flashing, providing lower strength and wear properties. Changes in TPS from triangle to pentagon and from pentagon to hexagon produced higher tensile strength, at 11.16% and 12.15%, respectively. The Chimp Optimization Algorithm (ChOA) shows an optimal condition of hexagon TPS, AL of 2 kN, RS of 1800 rpm, and TS of 25 mm/min, whereas TOPSIS optimal condition are hexagon TPS, AL of 4 kN, RS of 1400 rpm, and TS of 50 mm/min. Confirmation experiments with optimal conditions shows, ChOA producing lower WR, CoF, and FF by 12.5, 2.56, and 1.54% than TOPSIS. Compared with TOPSIS, ChOA produced lower WR, CoF, and FF by 12.5%, 2.56%, and 1.54%.

Enhancing solar thermoelectric power generation with supercritical CO2 cooling: Hydraulic, thermal, and exergy analysis

This research investigates the dynamic behavior and impact of various factors on the hydraulic, thermal, and exergetic characteristics of a solar-based thermoelectric device using a pin–fin heatsink cooled by supercritical CO2. A comprehensive numerical model analyzes the heat dissipation and performance of the power generator, integrating a thermoelectric generator and a pin–fin heatsink with various pin shapes. Key geometric and operational parameters, such as the height of PN (P-type and N-type semiconductor) legs of the TEG, the number of thermocouples, operating pressure, Reynolds number, and CO2 temperature, are examined for a comprehensive performance assessment. The study highlights the superior performance of CO2 coolant over traditional water-cooling system. Near the critical temperature of CO2, enhanced heat transfer significantly boosts power output, conversion efficiency, and exergetic efficiency. For example, at 8 MPa, the TEG’s (thermoelectric generator) power output increases from 1.31 mW at 295 K to 2.35 mW at 310 K. Comparisons reveal that while water coolant lowers the cold side temperature more effectively, it results in reduced power output due to decreased temperature differentials and increased pressure loss. Conversely, CO2 coolant maintains higher cold side temperatures while having advantages in power output. At 315 K, the cold side temperature with water is 315.7 K compared to 346.7 K with CO2. Increasing the number of thermocouples from 18 to 32 for a leg height of 1 mm leads to an approximate 102.3 % increase in voltage. Raising the PN leg height from 1 mm to 2 mm for an NTC of 50 results in a nearly 99.8 % increase in voltage. Lozenge-shaped fin produces a peak power output of 2.73 mW, while square fin generates 2.62 mW. This research underscores CO2’s potential as a high-performance coolant in solar thermoelectric applications, offering insights into optimizing system design for maximum efficiency.

FABRICATION AND CHARACTERIZATION OF AA6082-T6 PRODUCED BY FRICTION STIR ADDITIVE MANUFACTURING

The machinability of aluminum alloy (Al-6082) has the scope of enhancement by integrating Friction Stir Processing (FSP) with tool geometry, tool shape and different tool materials. In this research, the role of tool pin shape has been studied by experimenting on various tool shapes (square, hexagonal and octagonal) with the aim of machinability improvement. In FSP, the tool rotation speed is 930[Formula: see text]rpm and tool travel speed is 26[Formula: see text]mm/min. The specimens have undergone tensile, microhardness and microstructure testing using optical microscope and scanning electron microscopy. The percentage elongation has been increased from 15% to 29% in the case of the octagonal-shaped tool pin; similarly, the (Vickers’) microhardness value is 14.6% higher than the square- and hexagonal-shaped tool pins. Among these tool pin shapes, the octagonal-shaped tool pin succeeded in providing the best-in-class machinability performance on Al-6082 T6 alloy with FSP. It may unveil the newer scopes of FSP on Al-6082 for automotive components assembly and other similar applications.

Experimental investigation of friction stir welding with special spherical ball shoulder different probe tools and parameters for enhanced material properties of AA2219 aluminium alloy

This research investigates the impact of unique spherical ball shoulder enhancement tool pin configurations on the friction stir welding (FSW) of AA2219 aluminum alloy under various parameters. FSW was performed using three different pin shapes: square, hexagonal, and octagonal. Testing samples were prepared using an L9 orthogonal array layout with varying welding parameters. The material behavior in the three distinct weld zones was evaluated for each pin configuration. Results indicated superior microhardness values in the heat-affected zone (HAZ) and thermo-mechanically affected zone (TMAZ) compared to the weld nugget zone. Elemental composition analysis of the TMAZ revealed significant differences, highlighting the influence of thermal stress and material behavior due to the tool pin and shoulder configuration. The square-headed tool demonstrated improved tensile strength and microhardness. Optimal welding performance was achieved with a spindle speed of 1000 RPM, a travel speed of 25 mm/min, and a tilt angle of 3°. Variations in Cu content in the TMAZ and HAZ underscored localized modifications within the material structure, driven by the spherical ball spinning effects on the shoulder. Tensile tests showed that welds made with the square pin consistently exhibited higher tensile strength compared to those made with hexagonal and octagonal pins.

Influence of tool geometry on mechanical and microstructural characteristics of friction stir welded cast alloys

Abstract Cast alloys find suitable applicability in aerospace sector owing to low porosity, high specific strength, corrosion resistance, fluidity and good machinability. The investigation focuses on friction stir welding (FSW) of cast A356 and A2014 alloys with varied range of process parameters, namely tool pin shape (cylinder, threaded cylinder, square, and conical), tool rotation speed (1800–2100 rpm) and welding speed (10–25 mm × min−1). Experimentation on stirwelding was performed based on selected tool pin shape between varied tool rotation and welding speed. The output responses, namely Ultimate tensile strength (UTS) and micro hardness, have been evaluated to study the effect of each tool. The microstructural characteristics of the weld samples were analyzed using optical microscope and scanning electron microscope (SEM) technique. The microstructural observation unveiled that complete fusion prevails between the parent alloys devoid of micro porosities and segregations. The re-crystallization effect resulted in the finer grains. The cylinder-shaped tool with a thread and square shaped tool rendered better strength and hardness properties of 136.6 MPa and 109.4 HV, respectively.

Enhancing the Robustness of Hybrid Metal-Composite Connections Through 3D Printed Micro Penetrative Anchors

This work proposes a novel solution for manufacturing hybrid metal-composite joints, in which different pin shapes are evaluated for their capability to penetrate long carbon fiber epoxy composites successfully and for the mechanical behavior determined by each configuration. On the metal side, pins are manufactured by Laser Powder Bed Fusion (LPBF), downsizing the currently adopted solutions and, at the same time, developing new blocking features aimed at enhancing the mechanical properties of the joint. The different configurations were evaluated in two distinct experiments: the first to evaluate the induced defects in the composite substrate and the second to characterize the mechanical behavior of the joint. It emerges that smaller pins produce much less damage and misalignments in the composite structure with respect to the conventional pin solution, whereas the new “blocking features” configurations consistently increase maximum pullout load and energy with respect to the conventional pin solution, with the same level of fiber damage.

Optimization of Pin Type Single Screw Mixer for Fabrication of Functionally Graded Materials

The direct ink writing (DIW) process, used for creating components with functionally graded materials, holds significant promise for advancement in various advanced fields. However, challenges persist in achieving complex gradient variations in small-sized parts. In this study, we have developed a customized pin shape for an active screw mixer using a combination of quadratic B-Spline, the response surface method, and global optimization. This tailored pin design was implemented in a two-material extrusion-based printing system. The primary objective is to facilitate the transformation of material components with shorter transition distances, overcoming size constraints and enhancing both printing flexibility and resolution. Moreover, we characterized the transition delay time for material component changes and the mixing uniformity of the extruded material by constructing a finite element simulation model based on computational fluid dynamics. Additionally, we employed a particle tracking method to obtain the Lyapunov exponent and Poincaré map of the mixing process. We employed these metrics to represent and compare the degree of chaotic mixing and dispersive mixing ability with two other structurally similar mixers. It was found that the optimized pin-type mixer can reduce the transition delay distance by approximately 30% compared to similar structures. Finally, comparative experiments were carried out to verify the printing performance of the optimized pin-type active mixer and the accuracy of the finite element model.

Enhanced performance of pinned metal foam heat sinks with dielectric coolant – A pore-scale numerical study

Recent advancements in the development of microprocessors have resulted in the design of smaller microchips with improved performance. The new designs require proper cooling systems to prevent performance degradation and permanent damage to the chips. Extended surfaces, including fin, pin, or metal foam, are one of the prominent approaches in cooling systems designs. So far, there has been limited research, especially considering pore-scale analysis on the combination of pin/fin with metal foam, which is expected to offer promising cooling performance. This study aims to evaluate the performance of pinned metal foam heat sinks with dielectric coolant as a potential cooling system for microchips. A three-dimensional pore-scale numerical model is developed to analyze the performance of the proposed heat sinks. The effect of different parameters such as Reynolds number, heat flux, pore density, and different pin shapes are investigated. The results reveal that at a Reynolds number of 100, almost all the metal foam heat sinks enhance the heat transfer performance, which can be as large as 22% in some cases. Furthermore, adding pins increases the heat energy dissipation with a slight penalty of pressure drop depending on its hydrodynamic adaptation. Too dense or loose metal foam either increases the pressure drop or decreases the heat transfer rate, deviating from the optimum range. Lastly, it is revealed that heat flux from the heater does not significantly change the performance of the pinned metal foam heat sinks.

Research on strain aging behavior of ultra-high strength dual-phase steel

The bake hardening value is one of the vital strength indexes of dual-phase steel, representing the strengthening ability of materials after pre-strain and baking, playing an important role in vehicle safety and lightweight design. Studying and improving the strain aging mechanism of dual-phase steel helps one to understand the material characteristics and enhances its utilization value. However, the ultra-high strength dual-phase steel is often prone to fracture outside the gauge length of a tensile specimen of the bake hardening value test. No suitable theory explains the fundamental law of dislocation pinning during the saturation stage at present. This paper used FEA, DIC, SEM, TEM, internal friction, and metallographic methods to study the strain aging behavior of dual-phase steels under different pre-strain, bake time, and bake temperature conditions. The results show that the fracture outside the gauge length is related to factors such as the uneven distribution of pre-strain and the ultra-high upper yield strength. The rolling pin shape tensile specimen testing has successfully solved this testing problem. The measured results at the saturation stage of dislocation pinning are in good agreement with the fitting results of the dislocation pinning strengthen mechanism based on the probability event quantization assumption.

Enhancement in wear-resistance of 30MNCRB5 boron steel-substrate using HVOF thermal sprayed WC–10%Co–4%Cr coatings: a comprehensive research on microstructural, tribological, and morphological analysis

The rotavator blade, a part of an agricultural equipment rotavator, is used for the soil bed preparation. These blades have direct interaction with soil in agricultural land. Bad, rocky, gravel, sandy, and high rough-hard texture of soil are the main factor to damage the surface of the rotavator blade and a high wear rate is observed. This causes to decrease in the overall life of a rotavator blade. It also changes the geometry of the rotavator blade after a few operations, and that all effects the performance capability of this blade. Hence HVOF (High-velocity oxy-fuel) is used to modify the surface that improved wear resistance of the rotavator blade's surface. Feedstock powder used for the coating is WC–10%Co–4%Cr with Ni–20%Cr as a bond coat on 30MNCRB5 steel substrate (Rotavator blade's material). Six samples are prepared to test it on the Pin-On-Disc wear testing apparatus to determine the wear rate, weight loss, cumulative volume loss and linear wear rate, three bare 30MNCRB5 steel and three WC–10%Co–4%Cr coated samples are prepared with 8 mm diameter and 30 mm length in a cylindrical pin shape. Coated samples are characterized using the XRD (X-ray diffraction), SEM (Scanning electron microscope) with EDAX (Energy-dispersive spectroscopy), and X-ray mapping techniques. Worn out surfaces of bare 30MNCRB5 steel and WC–10%Co–4%Cr coated samples are investigated using the SEM (Scanning electron microscope) to study the microstructure of worn surface that helped out to identify the wear behavior. The HVOF (High-velocity oxy-fuel) spray coating drastically improved the surface to defend it from wear, and very less weight loss was seen in the WC–10%Co–4%Cr coated samples as compared to bare 30MNCRB5 steel material. Weight loss determined by the bare (30MNCRB5) material at 40N, 50N, 60N loads are 2.996 × 10−3 Kgm, 3.003 × 10−3 Kgm, 3.123 × 10−3 Kgm, and coated (WC–10%Co–4%Cr) sample at 40N, 50N, 60N loads are 0.006 × 10−3 Kgm, 0.030 × 10−3 Kgm, 0.038 × 10−3 Kgm respectively.

SPH Simulation of Pin Shape Influence on Material Flow in Friction Stir Welding (FSW)

SPH Simulation of Pin Shape Influence on Material Flow in Friction Stir Welding (FSW)

Investigation of cell performance in pin geometry of solid oxide fuel cell considering blower power input

Enhancing fuel cell efficiency is crucial for promoting hydrogen adoption and reducing carbon emissions. Solid oxide fuel cell (SOFC) design affects power output and blower input, influencing current density and pressure drop. Computational fluid dynamics (CFD) simulations were used to investigate these factors across various designs. A comparison of pin configurations, the co-flow arrangement (fuel and oxygen in the same direction) had the highest hydrogen consumption (68.98 %), surpassing cross-flow and counter-flow cases (62.86 % and 68.22 %), leading to superior cell performance. Adjusting square pin width enhanced under-rib convection, improving cell performance but increasing blower input. S3 model (0.5 mm width) showed the highest performance improvement ratio (η = 1.1 %) from 0.25 mm width model (S1). Pin shape changes (square, diamond, triangle, circle) minimally affected performance, while staggered array design improved uniform flow and performance (η = 1.2 %). Findings of this study can be helpful to optimize SOFC performance by considering cell density, blower consumption, and flow distribution.

An experimental approach for achieving high strength dissimilar aluminium-magnesium joints: Application of tool pin profiles on different joint configurations

The goal of this study is to overcome difficulties in producing high-strength dissimilar aluminum-magnesium (Al-Mg) joints by friction stir welding (FSW). It analyses the effect of joint configurations and tool pin profiles on weld characteristics, with a focus on microstructural and mechanical aspects to establish optimal welding settings. The effect of process variables such as tool rotation speed (TRS) and traverse speed (TTS) on material flow and heat input is investigated. The findings reveal that the newly created joint configuration and tool pin shapes successfully link various Al-Mg FSW welds. The amount of heat used and the peak temperature reached during welding have a major impact on microstructure refinement and mechanical characteristics. The study investigates the relationship between heat input and the development of intermetallic compounds, emphasizing the need to optimize welding settings for strong interfacial bonding and joint integrity. The surface morphology and macrostructure of the welds are examined to determine their quality and faults. The tool pin profile influences material consolidation, flash defects, and surface peeling. Threaded conical tools outperform conical tools in terms of surface polish and flash expulsion. Overall, this study emphasizes the importance of changing joint configurations and selecting proper tool pin profiles when utilizing FSW to generate high-strength dissimilar Al-Mg couplings.

Influence of tool pin profile on the mechanical strength and surface roughness of AA6061-T6 overlap joint friction stir welding

This study presents the tensile strength and surface roughness resulting from friction stir welding (FSW) on the lap joint method using AA 6061 –T6. FSW is conducted by comparing three different tool pin shapes: hexagon, thread, and square. Overlap welding using the FSW method is challenging if machine parameters, such as spindle speed and feed rate, are incompatible. The experiment was conducted using a conventional milling machine with a spindle speed of 1400 -1750 rpm and a feed rate of 20 – 30 mm/min. The results show that a spindle speed of 1750 rpm and a feed rate of 30 mm/min using a square tool pin results in 83.5088 MPa ultimate tensile strength and 0.85 µm surface roughness (Ra), which is much better than hexagon and thread type tool pins. In addition, the overall results on all three tool pin shapes show that higher processing parameters increase tensile strength and surface roughness. This study revealed the effect of parameters on AA6061 –T6 and the resulting implications of mechanical strength and surface roughness.

An investigation of process parameter influences on dissimilar friction stir welding of cast aluminum alloy joints

ABSTRACTCast alloys find suitable employability in industrial applications favoring automotive and aerospace sectors owing to their high specific strength, low porosity, excellent fluidity, and machinability. The present study focuses on friction stir welding of cast aluminum alloys (AA356 and AA2014) with a varied range of process parameters, namely, tool pin shape (cylinder, cone, square, and threaded cylinder), tool speed (1800–2100 rpm), and tool feed (5–20 mm min−1). The novelty of the present work spotlights/features the implementation of L16 orthogonal design with the analysis of variance, grey relational analysis, fuzzy logic system, and artificial neural network approaches to contemplate the weld quality of cast joints. The microstructural analysis and grain size estimation is comprehended in the study. Regression models have been developed based on the analysis of variance. The prime factors favoring the ultimate tensile strength and microhardness were 2100 rpm, 10 mm min−1, and threaded cylinder shape. The findings from the analysis of variance and grey relational analysis are in concurrence with each other. The results of fuzzy logic showcased a substantial improvement in terms of grey relational grade. The results from the artificial neural network deliver rational evidence for the analysis of variance conducted on the selected tool pin shapes.

A computationally efficient multiphysics model for friction stir welding with polygonal pin profiles

This study aims to model temperature distribution in friction stir welding (FSW) using various backing plates and polygonal pin profiles since temperature significantly modifies the microstructure and texture of the weld zone affecting the weld quality such as weld strength, hardness, etc. The experimental results depict the importance of temperature on the grain size and tensile strength of the materials. However, determining the temperature at each point of the weld is difficult and expensive in the case of experiments. Therefore, in order to accomplish the objective, it is necessary to perform simulations. This paper presents a 3-D transient multiphysics model developed for FSW combining multiple physical phenomena such as heat transfer and structural mechanics in a unified framework, COMSOL. A viscoplasticity model is chosen as behavior for the AA1100 aluminum material using Anand viscoplasticity. It is computationally efficient and accurate. The model fidelity to the twin FSW process is achieved by considering temperature-dependent yield strength. Modeling results show the polygonal pin profile edges to be influencing the temperature. Increasing the number of faces on the pin sides leads to a higher temperature. Specifically, transitioning from an octagonal to a decagonal profile results in a minimal increase in total heat generation. As the pin shape approaches cylindrical, there is a gradual convergence in heat generation with that of a cylindrical pin. Experiments are also carried out that validate simulation results. Overall, the model is sufficient to twin the process for predicting weld quality and is Industry 4.0-compliant.

Influence of tool pin shape and rotation speed for friction stir spot welding of AZ91 magnesium alloy sheets

Abstract Light weight design is believed one of the most effective ways to enhance performance, reduce fuel consumption and harmful gases for air and land vehicles. Hence, welding lightweight metals like magnesium alloys is very important. Friction stir spot welding joints of 2 mm thick AZ91 magnesium alloy sheets by overlapping two of them were performed utilizing two welding tools having conical and triangular pin at 800, 1200 and 1600 revolution per minute (rpm) tool rotational velocities for each tool to identify the pin shape and rotation speed impact on microstructure and mechanical features of the created joints. The stir zones of the joints contained smaller grains, therefore had higher hardness in comparison to AZ91 base metal, thermo-mechanically affected zone (TMAZ) and heat affected zone (HAZ). The lowest hardness values were found in HAZ of the welds. Hardness fell slightly with a rise in rotation speed for both tools because of more heat input. Strength of the joints manufactured applying the triangular pin tool was better because this pin mixed materials better, thus created joints with bigger welding area and greater hardness. The strongest weld was fabricated by applying triangular pin tool and 1600 rpm.

An investigation on mechanical and wear behavior of friction-stir-processed hybrid AZ80/CeO2 + BN surface composite

The purpose of the present research is to develop hybrid AZ80/BN + CeO2 surface composite by friction stir processing (FSP). The impact of the pin shape on the metallurgical and mechanical properties is discussed. The microstructural features were studied employing Optical microscopy (OM) and Scanning electron microscopy (SEM). The results demonstrated that the agglomeration of reinforcement particles was considerably reduced when the pin shape was changed from cylindrical to conical and consequently improved particle dispersion in the stir zone. Wear resistance and the local shear strength are also increased by the conical pin in comparing cylindrical pin, which can be ascribed to the better distribution of CeO2 + BN within the stir zone.