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This friction welding process is characterized by the fact that there are no springs or deformations at the welding point, neither from the outside nor from the inside, and an unmistakable and ideal welding shape is obtained. The experiment was conducted on a flat sample without grooves, and it was welded, but it was very weak. Then grooves were made on the outer edge, and the welding took place, and it was a stronger weld. The idea was to increase the grooves to the end of the entire thickness of the sample, not just on the edge, and it was the strongest weld and optimal in shape. Several experiments were also performed. Experiments were conducted at different speeds until the four speeds used in this thesis were reached, the best of which was 1000 rpm. Experiments were conducted at different forces, and the four forces used became the best among those used in many experiments. The best of them was the force of 30 kgF, at a fixed time of 4 minutes, while the temperature was 200oC on surface welding at 4 minutes the welding process. For every speed and force, this appeared in the tensile test conducted on the samples after welding and was demonstrated that tensile dismantled force was 6160 N at 30 kgF of welding pressure. The study proved the success of this method, and it is also possible try it with other metals and changes it as necessary. [ABSTRACT FROM AUTHOR]

This paper is a study of mechanical properties and microstructure of rotary friction welded tungsten heavy alloy with aluminum alloy (AA). A plastic deformation is visible on AA side. Effects of friction time (FT) and friction pressure (FP) on the ultimate tensile strength (UTS) were studied by plotting graphs. The UTS of joints increases with increasing FP and FT and then decreases after reaching the maximum value. The fracture proceeds through the cleavage planes at the interface. Scanning electron microscopy for investigation of the fracture morphology and phase transformations taking place during friction welding process was used. Chemical compositions of the interfaces of the welded joints were determined by using energy-dispersive X-ray spectroscopy (EDS). EDS analyses across the interface of tungsten and nickel have not confirmed the diffusion to AA side. Microstructure of friction welds consisted of equiaxed grains formed due to dynamic recrystallization and coarse grains in the periphery region on AA side. [ABSTRACT FROM AUTHOR]

This friction welding process is characterized by the fact that there are no springs or deformations at the welding point, neither from the outside nor from the inside, and an unmistakable and ideal welding shape is obtained. The experiment was conducted on a flat sample without grooves, and it was welded, but it was very weak. Then grooves were made on the outer edge, and the welding took place, and it was a stronger weld. The idea was to increase the grooves to the end of the entire thickness of the sample, not just on the edge, and it was the strongest weld and optimal in shape. Several experiments were also performed. Experiments were conducted at different speeds until the four speeds (630, 800, 1000, 1250 rpm) used in this thesis were reached, the best of which was 1000 rpm. Experiments were conducted at different forces, and the four forces (20, 25, 30, 35 kgF ) used became the best among those used in many experiments. The best of them was the force of 30 kgF (300 Newton), at a fixed time of 4 minutes, while the temperature was 200oC on surface welding at 4 minutes the welding process. For every speed and force, this appeared in the tensile test conducted on the samples after welding and was demonstrated that tensile dismantled force was 6160 N at 30 kgF of welding pressure. The study proved the success of this method.

Copyright of China Forest Products Industry is the property of China Forest Products Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dissimilar metal welding is seeing growing adoption across industries to enhance structural functionality and efficiency. Achieving high-quality, defect-free dissimilar weld joints requires a comprehensive understanding of the interrelationships between the welding-induced microstructural changes and the material's performance characteristics, particularly its fracture-related properties. This study investigates the impact of microstructural changes on the fracture toughness of dissimilar welds between structural low-carbon steel (S355J2) and austenitic stainless steel (SS316L) prepared using the Rotary Friction Welding (RFW) technique. Welding preforms were created from respective pipe pup pieces. The evaluation involves microstructural analysis, tensile testing, hardness testing, and fracture toughness testing using compact tension specimens derived from various zones of the weld joints. Results revealed significant microstructural differences across the weld joint. The weld region exhibited stable hardness with a maximum of 208 HV1 in S355J2′s thermo-mechanically affected zone (TMAZ). High tensile strength (Ultimate Tensile Strength 540 MPa, Yield Strength 367 MPa) with failures mainly on the S355J2 side. The fracture toughness (KQ) matched parent metal values, with the RFW weld centre line (WCL) showing superior crack tip opening displacement (CTOD) of 0.35 mm. Fractography generally indicates ductile failure.

This research investigates the inherent radial non-uniformity within the rotary friction welding process, particularly concerning microstructure attributes like grain size, grain boundaries, misorientation angles, and interlayer presence along the radial axis. SS321-AA2219 rotary friction welding was carried out with and without an AA6061 interlayer. The numerical thermal model suggests increase in temperatures from the center to the periphery, due to non-uniform heat generation. Also, dissimilar material across the interface resulted in an asymmetric temperature profile along axial direction. Plastic deformation on the Aluminum side suggests dynamic recrystallization and grain refinement, whereas pronounced low-angle grain boundary (LAGB) formation near the SS side interface validates dynamic recovery. A radial non-uniformity in microstructure is observed, with metrics such as average grain size, LAGB fraction, and misorientation showing an increase from the center towards the periphery. The insertion of an interlayer alters process dynamics, manifesting in reduced temperatures and heightened forces, resulting in a more consolidated joint by enhancing the strength by 31 %. Interdiffusion of elements across the interface formed Fe-Al intermetallic compounds (IMC) confirmed with X ray diffraction. Fractography analysis elucidates the presence of rubbing marks and facet surfaces in interlayer-less joints, while joints with interlayer display sticking and dimples.

The feasibility of welding a CuAlBe SMA by continuous drive friction welding was evaluated. The metallurgical state (annealed/quenched) before welding and frictional pressure (5 and 10 MPa) were varied and their effects on joint quality were analyzed. Static tensile tests, microhardness, thermal analysis by DSC, and optical microscopy were carried out to characterize the welded joint. The results indicated joints of excellent thermomechanical quality. The welding zones are well-defined, narrow, and have a very refined microstructure compared to the base metal. The phase transition temperatures along the welded assemblies were not changed when welding was performed on the quenched samples, except in the welding zone of the sample welded with 10 MPa. Maximum tensile strength was obtained by using maximum friction pressure during welding of the annealed alloy (quenching after welding). To fill the gap in bibliographical research in this field of study, this work innovatively presents the possibility of welding Cu-based SMAs by rotary friction, including the welding of quenched parts without the need for subsequent heat treatments and without compromising the shape memory effect.

The objective of this experimental study is to utilize rotary friction welding (FW) for assembling similar polyamide materials. The application of the SVM approach enables the development of a predictive model for estimating mechanical properties in RFW processes. Furthermore, the optimization of RFW parameters through GA proves pivotal in selecting optimal welding conditions, providing a variety of choices. The welding parameters considered in this study included rotation speed at five levels and traverse speed at three levels. The strength of the welded samples was characterized by a tensile test. Additionally, temperature measurements were taken to determine the maximum temperature in the joint area. The results demonstrated the dependence of tensile strength and maximum temperature on the rotation speed. Maximum tensile strength is achieved at an optimal rotation speed. Moreover, analysis of variance (ANOVA) indicates that rotation speed is the parameter most influenced by tensile strength. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) stands out as a biomaterial with immense potential, primarily owing to its innate biodegradability. Conventional methods for manufacturing PLA encompass injection molding or additive manufacturing (AM). Yet, the fabrication of sizable medical devices often necessitates fragmenting them into multiple components for printing, subsequently requiring reassembly to accommodate the constraints posed by the dimensions of the AM platform. Typically, laboratories resort to employing nuts and bolts for the assembly of printed components into expansive medical devices. Nonetheless, this conventional approach of jointing is susceptible to the inherent risk of bolts and nuts loosening or dislodging amid the reciprocating movements inherent to sizable medical apparatus. Hence, investigation into the joining techniques for integrating printed components into expansive medical devices has emerged as a critical focal point within the realm of research. The main objective is to enhance the joint strength of PLA polymer rods using rotary friction welding (RFW). The mean bending strength of welded components, fabricated under seven distinct rotational speeds, surpasses that of the underlying PLA substrate material. The average bending strength improvement rate of welding parts fabricated by RFW with three-stage transformation to 4000 rpm is about 41.94% compared with the average bending strength of PLA base material. The average surface hardness of the weld interface is about 1.25 to 3.80% higher than the average surface hardness of the PLA base material. The average surface hardness of the weld interface performed by RFW with variable rotational speed is higher than the average surface hardness of the weld interface performed at a fixed rotating friction speed. The temperature rise rate and maximum temperature recorded during RFW in the X-axis of the CNC turning machine at the outer edge of the welding part surpassed those observed in the internal temperature of the welding part. Remarkably, the proposed method in this study complies with the Sustainable Development Goals due to its high energy efficiency and low environmental pollution. [ABSTRACT FROM AUTHOR]

The main objective of this study is to join SA 213 T11 and SA 213 F12 low alloy steel (LAS) tubes using rotary friction welding (RFW) procedure and to optimise welding parameters (rotating speed, forging pressure and friction pressure). Response surface methodology (RSM) was used to maximise the tensile strength (TS) and fully deformed zone hardness (FDZH) of LAS joints by optimizing the RFW parameters. The mathematical models (MMs) were developed to predict TS and FDZH of LAS joints. The 3D response surfaces were generated using MMs, which show the optimum RFW model parameters for increasing the TS and FDZH of LAS joints. The direct effect of RFW parameters on performance characteristics of LAS joints was analyzed from response surfaces. The microstructural characteristics of LAS joints developed using optimized parameters were analyzed using optical microscopy. Results showed that the LAS joints developed using rotating speed (N) of 60 rps, friction pressure (FF) of 0.851 MPa/s, and forging pressure (FOF) of 0.851 MPa/s exhibited greater TS and WIH of 650 MPa and 515 HV0.5 respectively. The greater TS and FDZH of LAS joints is attributed to the evolution of widmanstatten ferrite and lower bainite structures in interface and narrower TMAZ. [ABSTRACT FROM AUTHOR]

This study investigates the microstructural and mechanical properties of dissimilar alloy 718/720Li joints, contemplated for use in hot-end applications of aircraft engine components with service temperatures of up to 730°C. Microstructural characterization, microhardness, and room-temperature tensile tests were performed, followed by high-temperature tensile tests (650°C) on both as-welded and post-direct aging heat-treated conditions to analyze the performance of weld joints at high temperature. Results indicate that the friction welded joint interface in its as-welded condition exhibits lower hardness (240 HV at the heat affected zone) than the alloy 718 base material due to the dissolution of strengthening precipitates. However, post-weld direct aging (DA) with an alloy 718 aging cycle has improved the microhardness to be comparable to the parent materials. The peak hardness value of 478 HV achieved at the interface region is 26% higher than the as-welded condition. The dissimilar 718/720Li FRW joints in direct aging condition show room and high-temperature tensile strengths of 1374 and 1172 MPa, respectively. Similarly, during low-cycle fatigue testing, 718/720Li FRW joints in direct aging condition withstand up to 3648 cycles, comparable to the low-cycle fatigue life of the alloy 718 parent material, with failures away from the FRW weld interface and into the alloy 718 base material. The cyclic softening and hysteresis trend obtained during low-cycle fatigue tests of dissimilar 718/720Li friction welded joints are comparable with alloy 718 parent material. The dissimilar 718/720Li friction welded joints have a peak stress of 1097 MPa, which falls between low-strength alloy 718 and high-strength alloy 720Li. These findings confirm that friction welding of dissimilar nickel-based superalloys, such as alloy 718 with alloy 720Li, is promising for adaptation in aero engine applications. [ABSTRACT FROM AUTHOR]

Investigation of the joining technology of 3D-printed parts into a large physical model has become an important research topic. Rotary friction welding (RFW) is one of the friction welding methods. Understanding the weld interface temperature changes in the weld center zone during RFW is critical because it is related to the weld quality of the welded parts using RFW. Traditionally, the number of revolutions is constant in the RFW. However, rare investigations focus on the fatigue specimen fabricated by RFW with variable rotational speed. This study used RFW with varying rotational speeds to fabricate fatigue specimens. The ANSYS software was used to predict the temperature history of rotary frictionally welded dissimilar polymer rods fabricated by a computer numerical control (CNC) turning machine with variable rotational speed. The RFW experiment of ABS/PC dissimilar polymer rods was conducted to investigate the temperature history and compared with the simulation results. It was found that the temperature history profiles were in good agreement with the experimental and simulation results. Compared with the weld interface heating rate obtained from the experimental results, the simulation results has average discrepancy rate about 4.48 %. Compared with the maximum temperature of the weld interface obtained from the experimental results, the simulation results has average discrepancy rate about 3.16 %. The fatigue life can be increased by approximately 1.4 times. Finally, a database of rotary frictionally welded dissimilar polymer rods fabricated by a CNC turning machine with variable rotational speed was proposed. The average Shore A surface hardness at the weld interface was enhanced by approximately 18 % compared to the base ABS material.

Rotary friction welding is one of the most crucial techniques for joining different parts in advanced industries. Experimentally measuring the history of thermomechanical and microstructural parameters of this process can be a significant challenge and incurs high costs. To address these challenges, the finite element method was used to simulate thermomechanical and microstructural aspects of the welding of identical superalloy Inconel 718 tubes. Numerical simulation results were used to compute essential mechanical and metallurgical parameters such as temperature, strain, strain rate, volume fraction of dynamic recrystallization, and grain size distribution. These parameters were subsequently verified using experimental test results. The Johnson–Avrami model was utilized in the microstructural simulation to convert thermomechanical parameters into metallurgical factors, employing a FORTRAN subroutine. The calculated thickness of the recrystallization zone in the wall was 480 and 850 μm at the tube wall's center and edge, respectively. These values were reported from experimental measurements as 500 and 800 μm, respectively. The predicted grain size changes from the center to the edge of the wall thickness, near the weld interface, ranged from 2.07 to 2.15 μm, comparable to the experimental measurements ranging from 1.9 to 2.2 μm. Various curves are also presented to explore the correlation between thermomechanical and microstructural parameters, with the experimental results revealing predictable microstructure evolutions correlated with thermomechanical changes. [ABSTRACT FROM AUTHOR]

The objective of this research work is to present the mechanism of rotary friction welding of two dissimilar steels (X70 steel and duplex stainless steel). The selected rotational speed was maintained during the welding process. The welded sample was characterized by optical microscopy and hardness measurements. The welding sequence was presented. The duration and the mechanism of different welding stages have been determined. Optical observation revealed distinct zones in the welded joint. The Vickers hardness profile showed the difference in hardness across the welded joint. [ABSTRACT FROM AUTHOR]

Welding can be defined as the principal joining method for metals. Welding can be broadly classified into Fusion welding and Solid-State welding. Material like brass, copper and especially aluminum cannot be joined using conventional welding techniques. Conventional welding techniques generates additional scrap, poor weld strength, cracks, porosity, dangerous to environment, slag insertion, and unable to weld materials of different mechanical properties that is why rotary friction welding technique which is a type of Solid-State Welding used extensively in joining metallic and non-metallic specimen with effectiveness. The objective of this work is to give a better-quality Weld solution using rotary friction welding technique and its comparison with the unwelded specimen. In this work Vertical milling machine powered by motor, a continuous drive method was utilized for Welding of Aluminum alloy rods of varying diameter from 10mm to 12mm respectively. In this work three step methodology is followed. Firstly, dimensions, geometry and rotary friction welded specimen of Aluminum were prepared on vertical milling machine. Secondly destructive testing is performed for the tensile, compression, fatigue, hardness, and impact strength of the welded and unwelded specimen. Finally finite element analysis is carried out using experimental data resulted that the ultimate Tensile Strength of rotary friction welded specimen is 68% as that of unwelded specimen. As for Compression testing a significant decrease in length of 1.33% and increase in area of 8.88% is observed While in case of unwelded specimen compression is small i.e. Decrease in length is 0.61%, increase in area is 1.29%. In fatigue testing initially 1 N load is applied welded specimen tend not to fracture. Upon applying 24 N load welded specimen is fractured after 11 min 9 sec with a fatigue strength of 248 MPa(36Ksi). Impact Strength of rotary friction welded specimen is 2142.85 J/m and unwelded specimen is 2100 J/m. It is also observed that there is an increase in hardness at welding interface. It is concluded that the rotary friction welded joint produces small heat-affected zone, resulting in uniform properties all over the part, joint become more efficient due to appropriate strength. [ABSTRACT FROM AUTHOR]

The aim of this work was to systematically find the optimum parameter combination using the response surface methodology (RSM) technique for welding of UNS S31803 tubes and to find the effect of parameters on mechanical and metallurgical properties. In the present work, the experimental investigations of friction-welded UNS S31803 tube joints are discussed in detail with characterization, radiography, and corrosion studies. The most important parameter that has the greatest impact on the tensile strength of the joints is the upset pressure, which is followed by heating time, heating pressure, and upset time. As the upset pressure and time increased, the joint strength also increased. The radiographic evaluation of the weldments revealed no significant flaws at the weld contact. In comparison to the parent metal zone, the microstructure indicated coarse grain structure in the weld metal zone, with grain orientation changing with upset time. For the optimal parameter combination, the austenite phase is primarily spread in the weld metal zone. In comparison to the partially deformed zone and the parent metal zone, the weld zone had lower hardness values. In the high strength and optimum parameter joints, fractography investigation revealed ductile failure. [ABSTRACT FROM AUTHOR]

A reliable local-fatigue assessment approach for rotary friction-welded components does not yet exist. The scope of this paper is to present test results for the fatigue behaviour of rotary friction-welded solid shafts made of structural steel S355J2G3 (1.0570) and an approach to fatigue assessment considering residual stress. In contrast to fusion-welded joints, components made by rotary friction welding usually contain compressive residual stress near the weld, which can significantly affect the fatigue strength. For this purpose, specimens were welded and characterised, including metallographic micrographs, hardness measurements, and residual stress measurements. The fatigue tests were performed with a constant amplitude loading in tension/compression or torsion with R = −1. All specimens were investigated without machining of the weld flash, either in the as-welded state or after a post-weld stress-relief heat treatment. In addition, the friction welding process and the residual stress formation were analysed using numerical simulation. The characterisation results are integrated into a fatigue assessment approach. Overall, the specimens perform comparatively well in the fatigue tests and the experimentally observed fatigue behaviour is well described using the proposed local approaches.

Welding is one of the most efficient techniques used throughout the decades. Among different techniques, friction welding being one of the most sufficient methods. In addition, polymer is one of the materials that has wide applications such as automobiles, aerospace, medical etc. The present study has been carried out to investigate the efficiency of similar friction-welded ABS terpolymer joints. The study was conducted using the rotary friction welding method. Three different cases of rotational friction speeds (605, 820, 1220 rpm) and times (15, 30, 60 seconds) were examined for each case by taking nine specimens. The tensile strength of welded joints is compared to that of ABS tensile specimen as received welding. The joint efficiency and burn-off length were calculated. The joint efficiency and burn-off results are compared and discussed. Then the study concluded that the optimum joint efficiency was 17.24% at 605 rpm and 60 seconds. The lower burn-off length was 2 mm at 605 rpm and 15 seconds.

Three-dimensional printing is widely used for manufacturing a variety of functional components. However, the 3D printing machine substantially limits the size of the functional components. Rotary friction welding (RFW) is a possible solution to this problem. In addition, there is a notable scarcity of research directed toward the domain knowledge of RFW involving dissimilar polymer rods containing metal powder. In this study, two welding specimens fabricated by polylactic acid (PLA)-containing copper powder and PLA-containing aluminum powder were joined using a turning machine. After RFW, a bending test and a Shore A surface hardness test were performed to investigate the weld quality. It was found that the bending strength of the welded parts fabricated by RFW of PLA and PLA-containing Al powder rods can be enhanced by about 57.5% when the welded part is placed at 45 °C. Surface hardness test results showed that the surface hardness of the weld interface is better than that of the 3D printed parts, and the average surface hardness of the weld interface from RFW of PLA and PLA is the highest. The surface hardness of the weld joint is about 3% higher than that of the base material. The surface hardness of the heat-affected zone is about 3% lower than that of the base material. The average peak temperature of the welded joint is the highest in the RFW of PLA-containing Al powder and PLA-containing Al powder rods. The average peak temperature of the weld joint can be as high as 160 °C. The average peak temperature of the welded joint is the highest in the RFW of PLA-containing Cu powder and PLA-containing Cu powder rods. The average peak temperature of the welded joint can be as high as 144 °C. A technical database was built for the selection of ambient temperatures used for the RFW of dissimilar polymer rods containing metal powder and three base materials. [ABSTRACT FROM AUTHOR]

In practice, the fused deposition modeling technique is widely used for producing various plastic functional components in the research and development stage. In particular, adhesive bonding is capable of bonding dissimilar materials quickly. However, the bonding strength is affected by human factors. In addition, bolts are also used to bond small 3D printed parts for making a large 3D physical model. However, this locking method is not resistant to vibration. The feature of fusion bonding of thermoplastic materials is known for its weldability. Rotary friction welding (RFRW) has low energy consumption in the welding field. In general, the weld quality is affected by the process parameters of RFRW significantly. The Taguchi method was used to optimize the process parameters of RFRW of dissimilar polymeric rods to reduce random efforts by the trial-and-error method. The most critical control factor is the weld time. The contribution percentage for the weld time, feed rate, rotational speed, and preheating temperature is 35.21%, 27.85%, 24.84%, and 12.10%, respectively. The optimal process parameters of the frictionally welded parts with better bending strength are the feed rate of 0.05 mm/s, preheating temperature of 50 ℃, rotational speed of 950 rpm, and weld time of 20 s. The bending strength of the frictionally welded parts can be enhanced by about 1.29 to 1.538 times. [ABSTRACT FROM AUTHOR]

The main task that the article introduces is the experimental study of how the geometry of contact surfaces affects the quality and mechanical properties of a rotary friction weld (RFW), as well as the findings of whether the RFW technology is suitable for the titanium alloy Ti6Al4V. The experiments were carried out for specimens with a diameter of 10 mm and were performed at 900 RPM. Three types of geometry were proposed for the RFW process: flat on flat, flat on 37.5° and flat on 45°. Based on these results, the best tested flat geometry was selected from the perspective of quality and economic efficiency. The welded joints were subjected to microstructural analysis, tensile testing, microhardness testing, and fractography, as well as spectral analysis of the fracture surface and EDS map analysis of oxygen. The flat geometry of the contact surface resulted in the least saturation with interstitial elements from the atmosphere. Fracturing in the RFW zone led to a brittle fracture with a certain proportion of plastic deformation. A pure ductile fracture occurred in specimens fractured in the HAZ region, where the difference in UTS values compared to specimens fractured by a brittle fracture mechanism was not significant. The average UTS value was 478 MPa. [ABSTRACT FROM AUTHOR]

It is generally accepted in the field of friction welding that the parameters of rotary friction welding affect mechanical properties. Accurate input is crucial at each process stage, especially in smart factories that use automated machines to produce workpieces. The input for each parameter must be precise. This research proposes a prediction parameter for rotary friction welding for aluminium round bar AA6063, which uses the adaptive-network-based fuzzy inference system (ANFIS) method. The condition, which includes rotational speed, welding time, and friction pressure was used to input the membership function. The ultimate tensile strength of the weld joint was used for the output of ANFIS. The results show that prediction can contribute to industrial applications by determining which parameters can be adapted to the application control for the automatic rotary friction welding process in a Smart Factory. [ABSTRACT FROM AUTHOR]

Rotary friction welding (RFW) has no electric arc and the energy consumption during welding can be reduced as compared with conventional arc welding since it is a solid-phase welding process. The RFW is a sustainable manufacturing process because it provides low environmental pollution and energy consumption. However, few works focus on the reliability of dissimilar polymer rods fabricated via RFW. The reliability of the frictionally welded components is also related to the ambient temperatures. This work aims to investigate the effects of ambient temperature on the mechanical properties of frictionally welded components of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) dissimilar polymer rods. It was found that the heat-affected zone width increases with increasing rotational speeds due to peak welding temperature. The Shore A surface hardness of ABS/PC weld joint does not change with the increased rotational speeds. The Shore A surface hardness in the weld joint of RFW of the ABS/PC is about Shore A 70. The bending strength was increased by about 53% when the welded parts were placed at 60–70 °C compared with bending strength at room temperature. The remarkable finding is that the bending fracture position of the weldment occurs on the ABS side. It should be pointed out that the bending strength can be determined by the placed ambient temperature according to the proposed prediction equation. The impact energy was decreased by about 33% when the welded parts were placed at 65–70 °C compared with the impact energy at room temperature. The impact energy (y) can be determined by the placed ambient temperature according to the proposed prediction equation. The peak temperature in the weld interface can be predicted by the rotational speed based on the proposed equation. [ABSTRACT FROM AUTHOR]

Similar rotary friction welding with AA6061-T6 rod material was carried out at four variations of rotational speed in order to study the effect of rotational speed on the joint properties. The increase in rotational speed produces higher hardness value in DRZ area, i.e. the lowest microhardness value in the DRZ area was 129 VHN at 380 rpm and increased to 192 VHN at 1700 rpm due to a grain refinement process that increased the hardness as the Hall–Petch equation. Otherwise, in the HAZ and TMAZ area, the microhardness profile has a decreasing trend due to the welding rotation increases. All welded joints have a lower strength than the base metal, about 68% for tensile and 83% for fatigue. The observations on the fracture surface of tensile and fatigue test showed that the fracture's area occurs in the same region where the lowest microhardness and roughness grain sizes occur. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rotary friction welding (RFW) is used in the production of drill pipes for solid mineral prospecting. The need for the creation of the lightened drill strings for high-speed diamond drilling of ultradeep wells dictates the necessity of a greater focus on the study of a weld zone and setting the RFW technological parameters. This paper presents the results of experimental studies of a welded joint of a drill pipe of the H standard size according to ISO 10097, made of the 30ХГСА (pipe body) and 40ХМФА (tool joint) steels under the cyclic loads. The authors evaluated the influence of the force applied to the workpieces in the process of friction of the contacting surfaces (force during heating), and postweld tempering at a temperature of 550 °С on the cyclic life of welded joints, under the conditions of alternate tension-compression at the cycle amplitude stress of ±420 MPa. The study determined that with an increase in the force during heating, the microstructure changes occur in the zone of thermomechanical influence, contributing to an increase in the fatigue strength of welded joints. The authors identified the negative effect of postweld tempering on the fatigue strength of welded joints, which is expressed in the decrease in the number of cycles before failure by 15–40 %, depending on the magnitude of the force during heating. The optimal RFW mode of the specified combination of steels is determined, which provides the largest number of cycles before failure: the force during heating (at friction) Fh=120 kN, forging force Ffor=160 kN, rotational frequency during heating n=800 Rpm, and upset during heating l=8 mm. A series of fatigue tests have been carried out at various values of the cycle amplitude stress of the welded joint produced at the optimal mode and the 30ХГСА steel base metal; limited endurance curves have been plotted. It is shown that the differences in the limited endurance curves of the pipe body material (30ХГСА steel) and the welded joint are insignificant. The obtained results are supplemented by the microhardness measurement data and fractographs of fractured samples, revealing the mechanism of crack propagation under the cyclic loads.

The main objective of this study was to analyze the microstructural characteristics and strength performance of dissimilar AISI 431 steel/AISI 1018 steel joints developed using rotary friction welding. The microstructural characteristics of different regions of dissimilar rod-to-plate joints were analyzed using optical microscopy. The tensile properties and microhardness of dissimilar rod-to-plate joints were evaluated to assess the joint performance. The microhardness distribution across the cross-sectional region of dissimilar rod-to-plate joints was recorded and correlated with the tensile failure. Scanning electron microscopy was used to analyze the fractured region of dissimilar rod-to-plate tensile specimens. Results showed that the dissimilar AISI 431 steel/AISI 1018 steel joints steel exhibited a tensile strength of 650 MPa, a yield strength of 452 MPa, and a % elongation of 18%. The microhardness of the weld interface (WI) was higher up to 515 HV0.5. The grain growth and resulting lower hardness in heat-affected zone (HAZ) are mainly responsible for the failure of the joints in HAZ only. The superior tensile properties and greater interface hardness of dissimilar AISI 431 steel/AISI 1018 steel joints are correlated with the evolution of finer grain microstructure in the WI zone.

Frictional heat induced morphological responses of austenitic alloys SUS304, A286, and Inconel 718 at the interface in rotary friction welding was focused in this study, addressing initiation, evolution of corona-bond and the formation of heat-pattern. Summative models that describe the location and width of corona-bond at initiation, the corona-bond evolution mode and the formation of heat-patterns were given. The results show that when the corona-bond initiates at 0.33 R ∼ R, it fills the interface to form a lens-shaped heat-pattern. Inside this morphology, recrystallized ultrafine grains are formed to provide a superior performance. When the corona-bond initiates at 0–0.33 R with a width >0.4 R, it spreads to periphery to form a straight-line-shaped heat-pattern. Inside this heat-pattern, deformed grains and sub-boundaries are formed. The tensile strength of straight-line heat-pattern is lower than that of lens-shaped heat-pattern. When the corona-bond initiates at 0–0.33 R with a width ≤0.4 R, it does not spread but concentrates itself at center to form a spindle-shaped heat-pattern consisted of a ‘spindle body’ at center and a ‘friction line’ at periphery. Spindle body corresponds to a region made up of equiaxed recrystallized ultrafine grains, whereas the friction line corresponds to recrystallized grains and substructured grains. The formation of the friction line makes neglectable effect on local the strength but it does lower the elongation, where the local elongation of the friction line decreases to 6%–9% compared to 18% of a spindle body.

Polylactic acid (PLA) stands out as a biomaterial with immense potential, primarily owing to its innate biodegradability. Conventional methods for manufacturing PLA encompass injection molding or additive manufacturing (AM). Yet, the fabrication of sizable medical devices often necessitates fragmenting them into multiple components for printing, subsequently requiring reassembly to accommodate the constraints posed by the dimensions of the AM platform. Typically, laboratories resort to employing nuts and bolts for the assembly of printed components into expansive medical devices. Nonetheless, this conventional approach of jointing is susceptible to the inherent risk of bolts and nuts loosening or dislodging amid the reciprocating movements inherent to sizable medical apparatus. Hence, investigation into the joining techniques for integrating printed components into expansive medical devices has emerged as a critical focal point within the realm of research. The main objective is to enhance the joint strength of PLA polymer rods using rotary friction welding (RFW). The mean bending strength of welded components, fabricated under seven distinct rotational speeds, surpasses that of the underlying PLA substrate material. The average bending strength improvement rate of welding parts fabricated by RFW with three-stage transformation to 4000 rpm is about 41.94% compared with the average bending strength of PLA base material. The average surface hardness of the weld interface is about 1.25 to 3.80% higher than the average surface hardness of the PLA base material. The average surface hardness of the weld interface performed by RFW with variable rotational speed is higher than the average surface hardness of the weld interface performed at a fixed rotating friction speed. The temperature rise rate and maximum temperature recorded during RFW in the X-axis of the CNC turning machine at the outer edge of the welding part surpassed those observed in the internal temperature of the welding part. Remarkably, the proposed method in this study complies with the Sustainable Development Goals due to its high energy efficiency and low environmental pollution.

Rotary friction welding (RFW) is a solid-state welding method that can address the melting point limitation of other welding types; however, the welded area remains at risk of failure due to fatigue during operation. Fatigue failure is difficult to detect and predict, making it a critical failure mode in engineering. Although many fatigue life prediction methods are available, they do not consider the impact of RFW parameters (such as pressure, speed, and friction time) on fatigue strength. Owing to their good mechanical properties and commercial viability, carbon steel of grades C35 and C45 is commonly applied to manufacture main parts in the automotive industry. This study centers on employing RFW to join C35 and C45, representing the first-ever instance of using this technique to weld them together. The primary goal of RFW for C35 and C45 is to construct optimum parts that meet specific design requirements and have a long fatigue life. Findings showed C45–C45 joints (77 %) were more tensile-efficient than C35–C35 joints (73 %). Dissimilar C35–C45 joints reached 60 % of C45 base metal and 76 % of C35 base metal in terms of tensile efficiency. RFW welds had lower tensile strength than their base metals. Optimal results came at 35 MPa friction pressure and 8–12 s friction time for both similar and dissimilar RFW joints using the Coffin–Manson method, dissimilar C33–C45 joint fatigue life improved by over 85 %, aligning C35 and C45 engineering aspects. SEM microstructure analysis showed two regions: non-deformed (NDZ) and plastically deformed (PDZ), with broader PDZ indicating better tensile strength. These findings enhance RFW's efficiency, promoting automotive part longevity and safety.

Understanding the fatigue behaviors of weld joints is significant in engineering practice. Rotary friction welding (RFW) can join the additively manufactured polymer components. Until now, no research has focused on the fatigue behavior of polymer components jointed via RFW. This study investigates the fatigue life of ABS/PC dissimilar components fabricated via RFW and proposes the fatigue mechanism based on the failure structure. This work uses five different cyclic loads and rotational speeds to investigate the fatigue life. The fatigue life of the RFW of ABS/PC dissimilar rods is better compared with the pure ABS and pure PC specimens due to weld and integrity microstructural changes resulting from the combination of ABS and PC materials. The number of cycles until the rupture of RFW of ABS/PC dissimilar components (y) can be determined by the cyclic load (x) according to the prediction equation of y = −838.25x2 − 2035.8x + 67,262. The fatigue life of the RFW of ABS/PC dissimilar components increase with the increased rotational speed. The number of cycles until rupture (y) can be determined by the different rotational speeds (x) according to the prediction equation of y = 315.21x2 + 2710.4x + 32,124. [ABSTRACT FROM AUTHOR]

Friction welding of aluminum alloys holds immense potential for replacing riveted joints in the structural sections of the aeronautical and automotive sectors. This research aims to investigate the effects on the microstructural and mechanical properties when AA5083 H116 joints are subjected to rotary friction welding. To evaluate the quality of the welds, optical and scanning electron microanalysis techniques were utilized, revealing the formation of sound welds without porosity. The microstructural examination revealed distinct weld zones within the weldment, including the dynamically recrystallized zone (DRZ), thermo-mechanically affected zone (TMAZ), heat-affected zone (HAZ), and base metal (BM). During the friction-welding process, grain refinement occurred, leading to the development of fine equiaxed grains in the DRZ/weld zone. Tensile testing revealed that the weldment exhibited higher strength (YS: 301 ± 6 MPa; UTS: 425 ± 7 MPa) in the BM region compared to the base metal (YS: 207 ± 5 MPa; UTS: 385 ± 9 MPa). However, the weldment demonstrated slightly lower elongation (%El: 13 ± 2) compared to the base metal (%El: 15 ± 3). The decrease in ductility observed in the weldment can be attributed to the presence of distinct weld zones within the welded sample. Also, the tensile graph of the BM showed serrations throughout the curve, which is a characteristic phenomenon known as the Portevin–Le Chatelier effect (serrated yielding) in Al-Mg alloys. This effect occurs due to the influence of dynamic strain aging on the material's macroscopic plastic deformation. Fractography analysis showcased a wide range of dimple sizes, indicating a ductile fracture mode in the weldment. These findings contribute to understanding the microstructural and mechanical behavior of AA5083 H116 joints subjected to rotary friction welding. [ABSTRACT FROM AUTHOR]

In this work, dissimilar welded joints from AISI 1330 and AISI 4340 low-alloy carbon steels produced using rotary friction welding (RFW) are investigated. These steels are intended for the manufacture of exploration drill pipes: AISI 4340 — the tool joint and AISI 1330 — the body of the pipe. Statistical analysis based on response surface methodology (RSM), microstructural examination using scanning electron microscopy with backscattered electron diffraction (EBSD), and mechanical tests were performed to investigate the friction weld joints. Equations are derived for predicting the notch tensile strength, ultimate tensile strength, and relative elongation from RFW process parameters (heating pressure, forging pressure, rotation speed during heating, burn-off length). The results showed that the rotation speed during heating and the heating pressure to the greatest extent affect the quality of the welded joint. Parameters have been established that ensure obtaining the mechanical properties of the welded joint at the level of the base metal AISI 1330: heating pressure 60–80 MPa, forging pressure 120–140 MPa, rotation speed during heating 400 rpm, and burn-off length 4 mm. It is shown that the strength of the joint depends on the development of processes of mutual dynamic recrystallization at the steel interface and strain hardening in the thermomechanical affected zone. [ABSTRACT FROM AUTHOR]

Rotary friction welding (RFW) could result in lower welding temperature, energy consumption, or environmental effects as compared with fusion welding processes. RFW is a green manufacturing technology with little environmental pollution in the field of joining methods. Thus, RFW is widely employed to manufacture green products. In general, the welding quality of welded parts, such as tensile strength, bending strength, and surface hardness is affected by the peak temperature in the weld joint during the RFW of dissimilar plastic rods. However, hitherto little is known about the domain knowledge of RFW of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) polymer rods. To prevent random efforts and energy consumption, a green method to predict the peak temperature in the weld joint of dissimilar RFW of ABS and PC rods was proposed. The main objective of this work is to investigate the peak temperature in the weld joint during the RFW using COMSOL multiphysics software for establishing an empirical technical database of RFW of dissimilar polymer rods under different rotational speeds. The main findings include that the peak temperature affecting the mechanical properties of RFW of PC and ABS can be determined by the simulation model proposed in this work. The average error of predicting the peak temperature using COMSOL software for five different rotational speeds is about 15 °C. The mesh element count of 875,688 is the optimal number of meshes for predicting peak temperature in the weld joint. The bending strength of the welded part (y) using peak welding temperature (x) can be predicted by the equation of y = −0.019 x2 + 5.081x − 200.75 with a correlation coefficient of 0.8857. The average shore A surface hardness, impact energy, and bending strength of the welded parts were found to be increased with increasing the rotational speed of RFW. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the microstructure, grain size, and mechanical properties of the dissimilar AISI 316L/Inconel 718 (IN 718) rotary friction welded joints under both the as-welded and post-weld heat treatment (PWHT) conditions. Because of reduced flow strength at elevated temperatures, the AISI 316L and IN 718 dissimilar weldments exhibited more flash formation on the AISI 316L side. At higher rotating speeds during friction welding, an intermixing zone was created at the weld joint interface due to the material softening and squeezing. The dissimilar welds exhibited distinctive regions, including the fully deformed zone (FDZ), heat-affected zone (HAZ), thermo-mechanically affected zone (TMAZ), and the base metal (BM), located on either side of the weld interface. The dissimilar friction welds, AISI 316L/IN 718 ST and AISI 316L/IN 718 STA, exhibited yield strength (YS) of 634 ± 9 MPa and 602 ± 3 MPa, ultimate tensile strength (UTS) of 728 ± 7 MPa and 697± 2 MPa, and % elongation (% El) of 14 ± 1.5 and 17 ± 0.9, respectively. Among the welded samples, PWHT samples exhibited high strength (YS = 730 ± 2 MPa, UTS = 828 ± 5 MPa, % El = 9 ± 1.2), and this may be attributed to the formation of precipitates. Dissimilar PWHT friction weld samples resulted in the highest hardness among all the conditions in the FDZ due to the formation of precipitates. On the AISI 316L side, prolonged exposure to high temperatures during PWHT resulted in grain growth and decreased hardness. During the tensile test at ambient temperature, both the as-welded and PWHT friction weld joints failed in the HAZ regions of the AISI 316L side. [ABSTRACT FROM AUTHOR]

The objective of this work is to investigate the effect of Cu interlayer on the tensile strength and ductility of the rotary friction welded Inconel 600 and stainless steel 316 L joints, in welded and annealed conditions. Joints were made with and without Cu interlayer. The temperature and forces were recorded during rotary friction welding. The welded and annealed joints were subjected to tensile tests, microstructural analysis and fractography of fractured surfaces from tensile test samples. Microstructural observation at the joint interface revealed the elemental diffusion with minimal bulk intermixing of the base materials. The dynamic recrystallization led grain refinement was observed on the steel side and grain coarsening was noticed on the Inconel side, near the interface. A substantial severe plastic deformation zone was noticed in the interlayer region for the joint made with Cu interlayer. The strength and ductility of the joints with interlayer were 10.8% and 82.3% higher than the joints made without interlayer. Upon annealing, joint ductility improved by 14.2% and 8.8% for the joints made without and with interlayer, respectively. [ABSTRACT FROM AUTHOR]