Upset Pressure Research Articles

Optimization of Impact Strength in Dissimilar Materials by Using Friction Welding Process

Friction welding is a solid state process used mostly for joining dissimilar materials due to mass production with less time consuming. The aim of this work is to study the dissimilar joints of austenitic stainless steel and copper for evaluating the impact strength. The experiment is conducted by using Taguchi’s L9 orthogonal array for determining the value of impact strength. The input parameters such as friction pressure, upset pressure, rotational speed and burn-off length were considered and the optimum process parameter was determined based on the response of impact strength. The predicted value of impact strength was validated by conducting the confirmation run using optimum parameters. The analysis of variance (ANOVA) is conducted for the mean of impact strength.

Evaluation of fatigue fracture mechanism in a flash butt welding joint of a U75V type steel for railroad applications

Nowadays, U75V steel is widely used in high speed railway construction, and commonly jointed by means of flash butt welding procedure. Considering the fact that fatigue failure is the main failure mode of railways, to ensure an adequate service life of railways, especially railways in coastal areas, this work mainly investigated the fatigue fracture mechanism of flash butt welding joints of U75V rail steel. First, the flash butt welding joints were prepared under two sets of process parameters and certain welding joints were corroded beforehand. Then, the microstructure, hardness, S–N curve and fatigue fracture of welding joints were analyzed in detail. Finally, the fracture mechanism was comprehensively discussed by considering the effect of welding parameters. It was concluded that the fatigue performance of flash welding joint is mainly determined by the upset pressure. Higher upset pressure is conducive to improve the fatigue strength. The fatigue crack source of fractured specimens under the condition of corrosion environment is at interface area and at the subsurface of sample. Meanwhile, the corrosion fatigue life obviously reduces.

A Comparative Study of Artificial Neural Network and Response Surface Methodology for Optimization of Friction Welding of Incoloy 800 H

This article deals with the optimization of process parameters for friction welding of Incoloy 800 H rod and compares the results obtained by response surface methodology (RSM) and artificial neural network (ANN). The experiments were carried out on the basis of a five-level, four-variable central composite design. The output parameters were the tensile strength and burn-off length (BOL). They were considered as a function of four independent input variables, namely heating pressure (HP), heating time, upsetting pressure (UP), and upsetting time. The RSM results showed that the quadratic polynomial model depicted the interconnection between individual element and response. For optimizing the process parameters, ANN analysis was used, and the optimal configuration of the ANN model was found to be 4–9–2. For modeling aspect, a requisite trained multilayer perceptron neural network was rooted, and a quick propagation training algorithm was used to train ANN. The purpose of optimization was to decide the maximum tensile strength and minimum burn-off length of the welded joint which was done by varying the friction welding process variables. The order of importance of input parameters for friction welding of Incoloy 800 H was HP > UP > N > BOL. After predicting the model using RSM and ANN, a comparison was made for predicting the effectiveness of two methodologies. By analyzing the results, it was observed that as compared to RSM, ANN model was more specific.

Tensile Strength and Hardness Correlations with Microscopy in Friction welded Aluminium to Copper

Aluminium and copper are good conductors of heat and electricity, copper being the better conductor, is a costly metal indeed. On the other hand, aluminium is cheap, easily available and also has a lower density than copper. Hence, worldwide efforts are being made to partially replace copper wire. Solid state welding should be used to join aluminium to copper. This is because the use of fusion welding results in brittle phases formed in the weld interface. One of the solid state welding techniques used for joining aluminium to copper is friction welding. In this paper, an attempt has been made to join aluminium to copper by friction welding by varying the friction welding parameters, namely friction pressure, upset pressure, burn-off length and speed of rotation of the workpiece. Nine different friction welding parameter combinations were used during welding in accordance with ASTM standards and results have been reported. Tensile strength and hardness tests were carried out for each parameter combination. Optimum friction welding parameter combination was identified with respect to tensile strength. Scanning Electron Microscopy and Electron dispersive spectroanalysis were obtained to identify modes of fracture and presence of intermetallic phases for each friction welding combination with the aim to narrow down friction welding parameters that give good properties on the whole.

Parameter design and analysis in continuous drive friction welding of Al6061/SiCp composites

Continuous drive friction welding (FW) had found profound industrial applications as an economical solid state joining process. The welding parameters such as frictional pressure, upset pressure, burn off length and rotational speed were found to influence the quality of joints. In the present study, Al6061/SiCp rods were joined by friction welding. The welding trials were designed by using Taguchi’s L9 orthogonal array. Tensile strength and micro hardness of the joints were observed as the quality characteristics after each trial. The urge for parameter design had prompted the disclosure of a new integrated methodology based on technique for order of preference by similarity to ideal solution (TOPSIS) and grey relational analysis (GRA). The effectiveness of the proposed approach of T-GRA was validated by conducting a confirmation test and the field emission scanning electron microscope (FESEM) images of the fractured surface were also examined.

Experimental investigation of Ti–6Al–4V titanium alloy and 304L stainless steel friction welded with copper interlayer

Abstract The basic principle of friction welding is intermetallic bonding at the stage of super plasticity attained with self-generating heat due to friction and finishing at upset pressure. Now the dissimilar metal joints are especially popular in defense, aerospace, automobile, bio-medical, refinery and nuclear engineerings. In friction welding, some special alloys with dual phase are not joined successfully due to poor bonding strength. The alloy surfaces after bonding also have metallurgical changes in the line of interfacing. The reported research work in this area is scanty. Although the sound weld zone of direct bonding between Ti–6Al–4V and SS304L was obtained though many trials, the joint was not successful. In this paper, the friction welding characteristics between Ti–6Al–4V and SS304L into which pure oxygen free copper (OFC) was introduced as interlayer were investigated. Box–Behnken design was used to minimize the number of experiments to be performed. The weld joint was analyzed for its mechanical strength. The highest tensile strength between Ti–6Al–4V and SS304L between which pure copper was used as insert metal was acquired. Micro-structural analysis and elemental analysis were carried out by EDS, and the formation of intermetallic compound at the interface was identified by XRD analysis.

Investigation on strength of solid state Al6061/30%Al<SUB align="right">2O<SUB align="right">3 bonds for automotive applications using response surface methodology

Welding is an important joining operation with widespread applications in automotive components. Liquid state joining of aluminium-based composite materials in applications involving engine valve, drive shaft and axle was observed to create unnecessary metallurgical changes in the parent material, thereby reducing the joint strength. A solid state welding process could offer the required solution for this problem. Hence, the present work explores the possibility of obtaining strong joints with Al6061/30%Al2O3 composites by employing the process of friction welding (FW). The selection of proper levels of welding parameters like the rotational speed, burn-off length, frictional and upset pressure was essential to improve the strength of these bonds. Taguchi's L18 orthogonal array was used for conducting the experiments and the tensile strength of the bond was evaluated as the response. The response surface methodology (RSM) was used to form a quadratic model for the tensile strength and the prime welding condition for stronger joints was sorted out using the desirability analysis.

Parameter design in friction welding of Al/SiC/Al2O3 composite using grey theory based principal component analysis (GT-PCA)

Solid-state welding processes have widened the scope of joining metal matrix composites. The aim of this work was to study the possibility of producing good quality joints with Al/SiC/Al2O3 composites using continuous drive friction welding. Taguchi’s L9 orthogonal array was used to study the effect of welding parameters like frictional pressure, upset pressure, burn off length and rotational speed on the quality characteristics of joints. The quality of joints was evaluated by observing the tensile strength, elongation and micro hardness. An integrated approach of GT-PCA which combines the methodology of grey theory and principal component analysis (PCA) was used to predict the optimal level of friction welding parameters. Frictional pressure was identified as the prime parameter affecting the observed responses. Microstructure of the weld zone was examined using optical microscopy and the fractured surface was also investigated using the field emission scanning electron microscopy images.

Multi-objective optimization of friction welding parameters in AISI 304L austenitic stainless steel and copper joints

Friction welding is a solid-state joining technique, and joining of dissimilar materials has been witnessing tremendous development in various applications. In this study, friction welding is carried out in dissimilar materials, austenitic stainless steel and copper, which find application in power generators. The parameters such as friction pressure, upset pressure, rotational speed and burn-off length are considered to determine its influence on tensile strength, metal loss and weld time. Taguchi’s L27 orthogonal array is used for experimental design to maximize the tensile strength as well as minimize the metal loss and weld time. Optimal parameters are determined through multiple performance characteristics, and it is found that friction pressure of 22 MPa, upset pressure of 108 MPa, rotational speed of 500 r/min and burn-off length of 1 mm yield good mechanical and metallurgical properties.

Torsional Behavior of AISI 420/AISI 4340 Steel Friction Welds

Abstract The solid-state friction welding method, which is widely used in the automotive, machinery, aviation and aerospace industry, was applied in this study. AISI 420 martensitic stainless steel, which is difficult to join by using fusion welding methods, and AISI 4340 tempered steel, which is commonly used in the automotive industry, were joined. During the welding process, three different rotations as 700, 1000 and 1300 rpm were used and parameters such as friction pressure, friction time, upset pressure as well as upsetting duration were kept constant. After the welding process, welded joints were examined macroscopically and microscopically, and their microhardness were measured. Then, torsion tests were performed on these samples. During the torsion tests, the samples fractured outside the welded joint regions. Thus, it was concluded that torsional strength of welded joint zones was high and AISI 420 and AISI 4340 steels were smoothly joined by friction welding.

Optimization of Friction Welding Parameters for AA6061-T6/AA2024-T6 Joints Using Taguchi-Simulated Annealing (TSA) Algorithm

Friction welding is an economical solid state joining process which has gained industrial acceptance for producing dissimilar joints with light weight applications. In this work continuous drive friction welding was employed to produce AA6061-T6/AA2024-T6 joints. The process parameters which influence the quality characteristics of the joint like the frictional pressure, upset pressure, rotational speed and burn off length were varied in three levels and the experimental trials were designed by Taguchi’s L9 orthogonal array. Yield strength, ultimate strength and micro-hardness in the weld area were observed as the responses for the various trials. Weighted S/N (WSN) ratio was calculated for each trial by utilizing the weights generated by simulated annealing (SA) algorithm. The optimal levels were sorted out by taking the WSN ratio as a measure of performance and a confirmation experiment was conducted for validation. The results of ANOVA had revealed the significant contribution of upset pressure in affecting the quality characteristics.

Inprocess Quality Control through Propotionate Valve in Electrical Upsetting of Engine Valves

In regular electrical upsetting process, the process parameters were determined by the experience. During working, these parameters were constant and could not be controlled online. In this paper a new proportionate valve and various velocity top anvils, electrical upsetting system is introduced. Based on the bulb temperature measured at the time of operation proportionate valve will vary the upset pressure to obtain the bulb without crack or fold. The control strategy includes two key parts: sensing the temperature and controlling it by varying the power intensity in the circuit through controlling the upset pressure. And the different anvil position and anvil velocity will be used to change the bulb shape based on the valve profile. This control strategy also includes two key parts: Velocity of anvil is directly proportional to height of bulb, in various positions various velocity will be used to form a different shape of bulb without defects.

Investigation of Microstructure and Mechanical Properties of Friction Welded Aisi 316 and Ck 45 Steels

AbstractThis study has arisen from the necessity to manufacture an impeller and a shaft pair of a water pump from two different types of steels. The impeller has to have resistant to corrosion and the shaft has to have magnetic permeability property. It is deemed suitable to use the AISI 316 austenitic stainless steel performing high resistance corrosion for the impeller and Ck 45 carbon steel with magnetic permeability property for the shaft. The joining of AISI 316 and Ck 45 steels has been achieved by using the friction welding method. After welding process, the tests of tensile and micro hardness were applied, the microstructures were observed, and composition of elements was found in the welding zone. As optimum welding parameters, 100 MPa of friction pressure, 10 s of friction time, 200 MPa of upset pressure and 20 s of upset time were determined in 3000 rev/min rotation speed.

Tensile Strength Characteristic of Al6061-T6 and Al7003-T6 Aluminum by the Change in the Friction Welding Process Variable

Recently, the various welding methods are used in the coupling method of product for the streamlining of complex products, simplification of manufacturing process, and decreasing process time a variety of industries. In this welding area, the friction welding technique has many advantages such as the mass production of rapid and highly reliable product and eases of automation, reduction of process time etc. so the domestic/external many studies are conducting. In this study, the Spindle speed, Up-set pressure as the necessary process variables for friction welding were change variously by using the round bar specimen of Al6061-T6 and Al7003-T6 Aluminum material, so the friction welding performance of the specimen by each change was compared and analyzed. In order to comprehend the friction welding performance, the frictional pressure was fixed with 20MPa, the spindle velocity was changed with 1,000, 1,500, 2,200rpm, and the Up-set pressure was changed with 35, 50, 65MPa for producing, so the performance by the specimen was compared and analyzed through the final tensile strength test. In addition, the effects of the friction welding on the specimen were examined through the analysis on the welding part hardness of the each friction welded aluminum specimen. In the result of the study, it showed the highest welding characteristic with the tensile strength 250.5MPa by applying 1,000rpm spindle velocity, 50MPa Up-set pressure compared to the lowest tensile strength 171.6MPa. In addition, as the result of hardness test, the hardness of specimen after conducting the friction welding of specimen decreased compared to the hardness of the pure material in the welding boundary, so it is judged that the measure to minimize the effects of the frictional heat by minimizing the friction welding time is needed.

The Friction Welding Characteristic Analysis of the Al 7075-T6 According to the Spindle Speed and Upset Pressure

The propeller shaft of rear-wheel drive vehicle is an axis which transfers power from an engine to rear-wheel through differential gear box. In this study, we studied the properties of friction welding required to produce the aluminum propeller shaft of lightweight rear-wheel-drive vehicle. We studied welding property to apply Al 7075-T6 aluminum yoke to automobile connects driving shaft and differential gear box. Here, solid phase friction welding method was used. In friction welding process, the principal parameter is spindle speed, up-set pressure and up-set time. We analyzed variable characteristics of friction welding strength according to the change of the spindle rate and up-set pressure. Friction welding strength was analyzed with ultimate tensile strength test with universal testing machine (UTM). The Al 7075-T6 was used as the round bar of the diameter of 25mm. The ultimate tensile strength was 552.3 MPa. It is 94% of ultimate tensile strength of pure Al 7075-T6 material. The main parameters of characteristics are discussed in detail based on analysis of the main effects plot and multi-vari chart. Finally, the core factors to get the maximum effect of friction welding investigated.

Fatigue properties of friction welded joints with flash by austenitic stainless steel and various machine part carbon steels

The purpose of this study was to achieve high performance and high function of an industrial product under low cost. The fatigue test of SUS304/S35C and SUS304/S55C friction welded joints with flash was investigated by the rotating bending fatigue test. The experimental results were as follows. (1) The broken part of friction welded joints of SUS304/S35C and SUS304/S55C was changed by amplitude stress, its part was toe of flash of S35C and S55C when amplitude stress was low. And, in the case of the high amplitude, it was specimen parallel part of SUS304. (2) The stress concentration factor of toe of flash of S35C and S55C was the increased with an increase in upset pressure. This tendency was slightly in the case of SUS304, and in the case of carbon steel, it was increased remarkably with increase of carbon. (3) When amplitude stress was low, the broken part of S35C and S55C joints was toe of flash, this fatigue strength was decreased remarkably with an increase in upset pressure. This main reason was the increased stress concentration factor. (4) When amplitude stress was high, the broken part of the SUS304 was the parallel part and the reason was that it was red hot. Heat occurred because of internal friction and low thermal conductivity. But this red-hot temperature was prevented completely by dropping water at 50 ml/min. (5) When the parallel part the length of SUS304 was < 25 mm, the amplitude stress broken by red-hot temperature was increased with a decrease in the parallel part length.

Evaluation of Mechanical and Metallurgical Properties of Dissimilar Materials by Friction Welding

Friction welding has been widely used to metals with dissimilar materials due to solid state joining process and shows good mechanical properties. In this study, the effect of mechanical and metallurgical properties of austenitic stainless steel (304L) and copper were experimentally investigated by tensile and hardness test while the metallurgical properties of optical, scanning electron microscopy and atomic force microscopy was used to analyze the microstructure of the welded joint. The joints were also examined with EDX line in order to understand the phases formed during welding. The material is evaluated by tensile test and their strength is determined and the hardness test measurements are examined in base metal and heat affected zone. The bonded materials of austenitic stainless steel and copper joint were produced by varying the friction pressure, upset pressure and rotational speed through Taguchi's orthogonal array. The highest tensile strength obtained in friction welded joint was 2.52% higher than parent material of copper. The effects of metallurgical characterization are discussed based on the microstructural studies.

SM45C 중실축의 마찰용접 기계적 특성에 관한 연구

AbstractIn the presented study, SM45C carbon steel parts were joined by friction welding. The welding process was carried out under optimized conditions using statistical approach. The study of SM45C is conducted with various combinations of process parameters. Parameter optimization, microstructure and mechanical property correlation are the major contribution of the study. The welded joints were produced by varying spindle revolution speed, friction pressure, upset pressure and burn-off length. Tension tests were applied to welded parts to obtain the strength of the joints. Fracturs properties were additionally obtained experimentally under fluctuated tensile loads. Microstructures using microphotographs were examined in the weld interface and weld region and heat affected zone and base metal and flash zone of welded parts. Finally, Hardness variations in welding zone and base metal were also obtained. Through these tests, the optimum conditions of parameters for ∅20 SM45C in friction welding were obtained when the friction spindle revolution was 1,950 rpm, the friction pressures was 30 MPs, upset pressures was 50 MPs.

해양차량 경량화용 마그네슘합금의 마찰용접 및 AE 특성

In this paper, friction welded joints were constructed to investigate the mechanical properties of welded 15-mm diameter solid bars of Mg alloy (AZ31B). The main friction welding parameters were selected to endure reliable quality welds on the basis of visual examination, tensile tests, impact energy test, Vickers hardness surveys of the bonds in the area and heat affected zone (HAZ), and macrostructure investigations. The study reached the following conclusions. The tensile strength of the friction welded materials (271 MPa) was increased to about 100% of the AZ31B base metal (274 MPa) under the condition of a heating time of 1 s. The metal loss increased lineally with an increase in the heating time. The following optimal friction welding conditions were determined: rotating speed (n) = 2000 rpm, heating pressure (HP) = 35 MPa, upsetting pressure (UP) = 70 MPa, heating time (HT) = 1 s, and upsetting time (UT) = 5 s, for a metal loss (Mo) of 10.2 mm. The hardness distribution of the base metal (BM) showed HV55. All of the BM parts showed levels of hardness that were approximately similar to friction welded materials. The weld interface of the friction welded parts was strongly mixed, which showed a well-combined structure of macro-particles without particle growth or any defects. In addition, an acoustic emission (AE) technique was applied to derive the optimum condition for friction welding the Mg alloy nondestructively. The AE count and energy parameters were useful for evaluating the relationship between the tensile strength and AE parameters based on the friction welding conditions.

Microstructure and mechanical properties of resistance upset butt welded 304 austenitic stainless steel joints

Resistance upset welding (UW) is a widely used process for joining metal parts. In this process, current, time and upset pressure are three parameters that affect the quality of welded products. In the present research, resistance upset butt welding of 304 austenitic stainless steel and effect of welding power and upset pressure on microstructure, tensile strength and fatigue life of the joint were investigated. Microstructure of welds were studied using scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis was used to distinguish the phase(s) that formed at the joint interface and in heat affected zone (HAZ). Energy dispersive spectroscopy (EDS) linked to the SEM was used to determine chemical composition of phases formed at the joint interface. Fatigue tests were performed using a pull–push fatigue test machine and the fatigue properties were analyzed drawing stress-number of cycles to failure ( S– N) curves. Also tensile strength tests were performed. Finally tensile and fatigue fracture surfaces were studied by SEM. Results showed that there were three different microstructural zones at different distances from the joint interface and delta ferrite phase has formed in these regions. There was no precipitation of chromium carbide at the joint interface and in the HAZ. Tensile and fatigue strengths of the joint decreased with welding power. Increasing of upset pressure has also considerable influence on tensile strength of the joint. Fractography of fractured samples showed that formation of hot spots at high welding powers is the most important factor in decreasing tensile and fatigue strengths.