Model development for numerical analysis of the bonding strength for friction welded lightweight structures

Rotary Friction Welding (RFW) is a solid-state welding process that is becoming increasingly popular due to advantages such as low weld heat input, high production efficiency, ease of manufacture, and environmental friendliness. Rotary friction welding can weld materials that are difficult to fuse using fusion welding techniques. The main objective of this study is to join SA 213 T12 and SA 213 F12 low alloy steel (LAS) tubes using a rotary friction welding process and to optimise welding parameters such as friction pressure, forging pressure, and rotating speed. To optimise the welding conditions, the response surface method (RSM) was applied. Empirical relationships were developed to predict tensile properties such as tensile strength (TS), yield strength (YS), elongation (EL), notch tensile strength (NTS), and notch strength ratio (NSR). Using the test results, the tensile properties of the rotary friction-welded low alloy steel (LAS) tubes were determined. The optimum process parameters for better tensile properties of the rotary friction welded joint are found to be rotation speed (N) 60 rps, friction pressure (FF) 0.851 MPa/s, and forging pressure (FOF) 0.851 MPa/s.

Recently, rotary friction welding has been used to join magnesium alloys. FRW uses friction heat to bond magnesium alloys with aluminium alloys. Combining these light alloys can provide many promising applications in the industry. The welding parameters such as friction and upsetting force, rotational speed, and welding time play a significant role in determining the joint strength. The paper presents a new approach to multi-objective optimisation of friction welding process parameters for AZ91D/AA6082 alloy joints. Multi-objective optimisation is based on artificial neural networks and genetic algorithms as non-conventional AI techniques. The methods were used to determine the following optimal welding process parameters: friction force, upsetting force and friction time for simultaneously maximised tensile strength and minimised metal loss (shortening) during welding. The ultimate tensile strength and metal loss of the friction welding joints were studied numerically and experimentally. Moreover, the influence of welding parameters on the ultimate tensile strength and shortening of friction joints was also studied. A genetic algorithm successfully found a set of welding parameters for which the joint strength increases from 24 to 81 MPA and the joint shortening decreases from 8.25 to 0.23 mm. The results show that a low friction force and upsetting force give a high value of tensile strength and the lowest shortening of the bimetal joints.

Mechanical behavior of rotary friction welding joints composed of laminated veneer bamboo substrate and bamboo dowel

Vibrations in friction welding

Three friction welding processes are compared for temperature, stresses and strains, as well as strain rates developed in the early phases of the processes, which are essential in their successful development. These are friction stir welding (FSW), linear friction welding (LFW) and rotary friction welding (RFW). Their common characteristic is the use of friction to generate adequate energy and raise temperature locally in order to create favorable conditions for welding at the interface between two parts. Although the mode of movement is different for each one of them, welds are produced through plastic deformation. The Lagrangian and coupled Eulerian-Lagrangian numerical models developed have produced results which are in qualitative agreement with experiments and have shed a light on the commonalities of these friction welding processes.

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 (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.

Rotary Friction Welding (RFW) is the progressive welding process, widely used in the manufacturing industry as appropriate for the joining of symmetrical geometry and shape of parts. The process offers several advantages like no fumes extraction, no release of harmful gases and no pollution, no melting at solid welding joints; high accuracy and precision of operation even at high speed; and less economical nature. Apart from the above advantages, another significant benefit is accompanied by the weld joint interface region, which produces the partial smelted state of the welded parts. This phenomenon is predominantly substantial for the welding of two unrelated material combinations and precisely where the slender heat-affected zone is encouraged. In this research work, the study has been conducted using the rotary friction welding process machine. The material selected for the study and experimentation for RFW process is austenitic stainless-steel SS304 (specimen dia. ϕ 12 and 14 mm) and SS316 (specimen dia. ϕ 10 and 14 mm). Several parameters have been studied for the RFW process like rpm, temperature, and pressure. A study of different mechanical properties like tensile strength, hardness, and microstructure analysis has also been carried out for the same welded specimen.KeywordsRotary friction weldingPressureTemperatureHardnessMicrostructureTensile test

Controlling martensite and pearlite formation with cooling rate and temperature control in rotary friction welding

This work investigates the microstructure evolution during the rotary friction welding (RFW) of Inconel 718 alloy. A cellular automata (CA) approach is implemented to evaluate a cylindrical component (at weld center and edge wall), predicting dynamic recrystallization (DRX) and grain size of friction welds. The input variables for RFW were rotational speed (500, 1000, and 1200 rpm), feed rate (2 mm/s), and feed distance (3.6 mm). The CA model is based on the Laasraoui-Jonas model and explains intricate grain transformation in terms of microstructure, temperature, strain, and strain rate. Calculated grain consists of very fine grain structure at the stir zone followed by the thermo-mechanical affected zone, where partial recrystallized microstructure was present. The average grain size was 2.5 µm, which is comparable to reported experimental values. The grain analysis revealed that temperature and strain are most affecting factors to attain a refined microstructure. The strain rates predicted for both center and edge locations of the weld were found to be higher as rotational speed increased. A steady strain distribution is noted at greater temperature for all the rotational speeds. The results of this work contribute toward the understanding of microstructure and mechanical response for RFW of Inconel 718.

The aim of this study is to investigate the rotary friction welding (RFW) technological parameters when welding two parts with medium carbon steel AISI 1030. Rotary friction welding has several parameters that can influence the quality of the weld joint. In this study, the adjustable and observable parameters are selected, i.e. friction pressure and friction time. The samples welded are observed in microstructure and their Rockwell hardness is measured to consider the effect of the parameters. The results reveal that friction pressure and friction time are the main factors of this welding process. Besides, the microstructures and hardness change in the welding zone because of the difference in the welding temperature.

The purpose of this study is to evaluate the accuracy of a simulation model for the Rotary Friction Welding (RFW) process of AA6061 aluminum alloy. RFW, widely used in the aerospace and automotive industries, is known for producing strong welds with minimal heat-affected zones (HAZ). Using ABAQUS software, a numerical model was developed to simulate key aspects of the process, such as heat generation, material flow, and axial shortening. The simulation results were compared with experimental data and previous studies to validate the model’s accuracy. The comparison demonstrated the model’s ability to closely replicate reality welding conditions, making it a reliable tool for optimizing welding parameters and improving the RFW process for AA6061.

Reduced-activated ferritic-martensitic steels are being considered for use in fusion energy reactor and subsequent fusion power reactor applications. Typically, those reduced activated steels can loose their radioactivity in approximately 100 years, compared to thousands of years for the non-reduced-activated steels. The commonly used welding process for fabricating this steel are electron-beam welding, and tungsten inert gas (TIG) welding. Therefore, Activated-flux tungsten inert gas (A-TIG) welding, a variant of TIG welding has been developed in-house to increase the depth of penetration in single pass welding. In structural materials produced by A-TIG welding process, weld bead width, depth of penetration and heat affected zone (HAZ) width play an important role in determining in mechanical properties and also the performance of the weld joints during service. To obtain the desired weld bead geometry, HAZ width and make a good weld joint, it becomes important to set up the welding process parameters. The current work attempts to develop independent models correlating the welding process parameters like current, voltage and torch speed with weld bead shape will bead shape parameters like depth of penetration, bead width, HAZ width using ANFIS. These models will be used to evaluate the objective function in the genetic algorithm. Then genetic algorithm is employed to determine the optimum A-TIG welding process parameters to obtain the desired weld bead shape parameters and HAZ width.

Experimental analysis of rotary friction joining process by EN1A bright mild steel under normal air and wet environment condition

Optimizing weld strength and microstructure in CP-titanium and 304 stainless steel friction welds with chromium interlayer