Pressure Welding Research Articles

Ultrasonic spot welding of aluminum-copper dissimilar metals: A study on joint strength by experimentation and machine learning techniques

Ultrasonic metal welding (USMW) is one of the solid state joining techniques which provides an alternative approach of joining soft and highly conductive materials like aluminum and copper in an impeccable way. Expectancy of good joint strength is an inevitable step to monitor, control and optimize the process parameters in this welding technique. In the light of this, regression model, artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are developed for predicting and simulating the joint strength for the USMW of Al-Cu sheets. The experiments are planned as per the full factorial design with three critical process parameters such as vibration amplitude, weld pressure and weld time to analyze tensile shear (TS) and T-peel (TP) failure loads. The analysis of variance (ANOVA) study explored that weld pressure has the most impact on the TS and TP followed by weld time and vibrational amplitude. Both of the artificial intelligence techniques were trained using the data attained from the experiment. Moreover, by comparing regression, ANN and ANFIS predicted results; ANFIS model provides less than 1% error and thus it can be considered as one of the reliable models to predict the weld strength in USMW process.

High cycle fatigue and fatigue crack propagation design curves for 5754-H22 and 6082-T6 aluminium alloys and their friction stir welded joints

Friction stir welding (FSW) is a dynamically developing version of pressure welding processes. Nowadays, learning the properties and behaviour of the welded joints is an important direction of investigation, especially under cyclic loading. The research work aimed (i) to demonstrate the behaviour of FS welded joints under cyclic loading conditions and (ii) to determine fatigue design curves for two aluminium alloys and their welded joints made by the FSW process. Experiments were performed on 5754-H22 and 6082-T6 aluminium alloys and their welded joints; high cycle fatigue (HCF) and fatigue crack propagation (FCG) tests were performed. Statistical approaches were applied during the experiments and the evaluation process. HCF design curves were determined based on the staircase method and FCG design curves were determined by our own previously developed six-step method. The results of the HCF and FCG tests on FS welded joints confirm the applicability of the applied FSW technology and show good correspondence with results of the comparative base materials and welded joints that can be found in the literature. Based on our experimental results and the evaluation methods used, statistically established parameters of HCF and FCG design curves were calculated.

Induction Pre-Heated Linear Friction Welding

A two-level factorial design of experiments (DOE) approach is used to study the effect of four factors (average rubbing velocity, weld pressure, burn-off distance, and preheat temperature) on two response variables (weld strength and energy input) for the induction heating and linear friction welding of AISI 1020 steel. Weld strength, as analyzed though three-point bending, was insensitive to all four of the design factors. Pressure, upset, and velocity show statistically significant inverse, linear, and linear relationships with energy used, respectively. Pressure has the largest effect on energy used, followed by velocity and upset.

Brushing for High Performance Cold Pressure Welded Bonds

Joining of steel and aluminum is a commonly applied manufacturing process to obtain lightweight components. Cold pressure welding by means of direct extrusion allows gaining high bond strengths between these two materials. The contacting surfaces are usually prepared by using scratch brushing to enhance the bond strength. Most studies have shown the benefit of the brushing whereas the resulting bond strength scatters. Variations in the parameters of the brush treatment are presumed to be a major cause for the variations in strength. Within the presented work, scratch brushing parameters are adjusted to further improve the resulting bond strength. Cracking of the surfaces at low strains is a beneficial effect to enhance the bond strength. Therefore, the crack formation of the surfaces brushed under different conditions is analyzed in tensile tests. Roughness, residual stresses and microstructural changes of the aluminum surfaces resulting from brushing processes are evaluated to enhance the understanding of the cracking mechanism. Concluding, the brushing parameters are adjusted to improve bond strengths up to the material strength of the used aluminum.

Investigation on the hot melting temperature field simulation of HDPE water supply pipeline in gymnasium pool

Abstract In view of the special needs of the water supply and drainage system of swimming pool in gymnasium, the correlation of high density polyethylene (HDPE) pipe and the temperature field distribution during welding was investigated. It showed that the temperature field distribution has significant influence on the quality of welding. Moreover, the mechanical properties of the welded joint were analyzed by the bending test of the weld joint, and the micro-structure of the welded joint was evaluated by scanning electron microscope (SEM). The one-dimensional unsteady heat transfer model of polyethylene pipe welding joints was established by MARC. The temperature field distribution during welding process was simulated, and the temperature field changes during welding were also detected and compared by the thermo-couple temperature automatic acquisition system. Results indicated that the temperature of the end surface of the pipe does not reach the maximum value, when it is at the end of welding heating. Instead, it reaches the maximum value at 300 sand latent heat occurs during the welding process. It concludes that the weld quality is the highest when the welding pressure is 0.2 MPa, and the heating temperature of HDPE heat fusion welding is in the range of 210 °C–230 °C.

EFFECTS OF GUIDING CHAMBER ON WELDING PRESSURE IN HOLLOW EXTRUSION DIE DESIGN OF AA7075

Porthole die extrusion has a great advantage in the forming of hollow section of aluminum alloy tube. This paper aims at the development of an extruding seam square tube of AA7075 high strength aluminum alloy. In order to increase the welding pressure of the hollow AA7075 tube in extrusion process, a special die feature has been created. Several different proportions of chamber structure in outlet of extrusion die have been designed. The finite element analysis software DEFORM 3D to analyze various design parameters on the load – displacement and the welding pressure have been studied. In this study, a different high proportion in material guiding chamber has been defined. The results showed that if a suitable material guiding chamber has been built then welding pressure can be increased rapidly. When the ratio of chamber height and length is 2:1 the increased welding pressure is the best.

Influence of Heating Friction Stir Spot Welding Process Parameters on Steel Aluminum Forming Quality

A lap welding experiment of DP590 steel and 6061 aluminum plate is carried out by using Heating Friction Stir Spot Welding (HFSSW) to study the influence of welding parameters on the forming quality. The results show that a lap joint with better forming can be obtained for the dissimilar metal of steel and aluminum. Under the condition that the rotating speed of the stirring tool is 1000r/min, the penetration depth, 0.2mm, the dwell time, 90s, the welding pressure, 0.2Mp, and the flow rate of cooling air, 20L/min, the forming quality of the surface of the joint line is good & bright, and the exit hole is also smaller. The mechanism of heat production is revealed in the following: the main heat is produced by the friction between the stirring tool shoulder and the welded part & between the probe and the welded part as well as by the latent heat resulted from the plastic deformation of the material in joint line during welding.

Fabrication and characterization of a bimetallic Al/Cu tube using the tube sinking process

In this work, two types of bimetallic tubes were fabricated from aluminum alloy and pure copper using the tube sinking process. The joint quality of the bimetallic tubes was evaluated using the so-called push experiment to determine the bonding shear strength. In addition, different microstructural studies were conducted in order to study the interface character of the layers. It was found that the bonding shear strength of the aluminum-clad copper was slightly higher than that of the copper-clad aluminum. Also, the former exhibited lower bonding shear strength variation than the latter. The discontinuous intermetallic components were detected at the latter interface for both types of bimetallic tubes. Also, it was interesting to note that a relatively thick aluminum oxide layer was found to be formed partially at the copper-clad aluminum tube layer interface. Signs of the cold pressure welding mechanism based on the film theory were indicated in aluminum-clad copper, whereas localized oxidation and wear phenomenon between the aluminum and copper layers deteriorated the bonding strength in copper-clad aluminum.

Visualization of metal flow and adhering of aluminum alloy in three-layer clad rolling

Metal flow and adhering in a three-layer aluminum clad sheet are visualized in roll bonding. It is shown that an interface condition between a core and two liner materials changes from slip mode to stick mode. It is recognized that oxide films are broken, and that newly formed surfaces are contacted like a pressure welding. Both surface profiles on a core and two liner materials are deformed, and many micro voids are formed in newly formed surfaces. From above results, a roll bonding mechanism of an aluminum clad sheet is suggested.

Formation of Gradient Structures in the Zone of Joining a Deformable Nickel Alloy and a Single-Crystal Intermetallic Alloy during Thermodiffusion Pressure Welding and Subsequent Heat Treatment

The possibility of formation of a high-quality solid-phase joint of an Ni3Al-based single-crystal intermetallic VKNA-25 blade alloy with a high-temperature deformable EP975 disk alloy by pressure welding is studied to create high-performance one-piece blisk unit for the next-generation aviation gas turbine engines and to decrease the unit mass. The influence of the conditions of thermodiffusion pressure welding under the hightemperature superplasticity of the disk alloy and the influence of heat treatment of welded joints on the gradient structures in the welded joint zone and the structure at the periphery of the welded samples are investigated.

Analyzing the weld strength of ultrasonic polymer welding using Artificial Neural Networks

Welding is considered as one of the most important process for the manufacturing industries. To be precise, the welding process has a supreme role to play in the automobile industry for fabrication and maintenance. Ultrasonic Welding (USW) is a very commonly used welding procedure in such industries, preferred because of its less processing time and versatility. In this study, three most influencing process parameters that includes welding pressure (P), weld time (Tw), and amplitude (A), are considered to determine the tensile strength of welded PC/ABS blend joints. The welding process is applied on a total of 26 samples and their tensile properties are obtained in terms of experimental results. It is clearly understood that all tensile strength of the joints welded by ultrasonic method is greatly influenced by all three process parameters. Further, with the help of data obtained from the experimentation, an Artificial Neural Network (ANN) based on Back Propagation model has been developed for analyzing the tensile strength of USW joints. By comparing the real time experimental results with the ANN predicted results, it is observed that the predicted and experimental models are in accordance with each other. This novel ANN model could be further employed for identifying the tensile strength of USW joints in various joining applications. Finally, the SEM images are analyzed to predict the nature of the weld condition.

Cyclic welding behavior of covalent adaptable network polymers

ABSTRACTSurface welding effect of covalent adaptable network (CAN) polymers enables self‐healing, reprocessing and recycling of thermosets, but little is known about their welding behaviors during repeated welding‐peeling cycles. In this article, we study the cyclic welding effect of an epoxy based thermal‐sensitive CAN. Surface roughness is generated by rubbing the sample on sandpapers with different grid sizes. The welding‐peeling cycles are repeated on the same pair of samples for five times, with roughness amplitude and interfacial fracture energy measured in each cycle. It is shown that the roughness gradually decreases during the repeated welding cycles, especially when a long welding time or high welding pressure is applied. Even though lower roughness amplitude promotes the contact area, the interfacial fracture energy reduces due to the increased BER activation energy after long‐time heating. A multiscale constitutive model is adopted, where we incorporate an explicit expression of interfacial contact area as a function of root‐mean‐square roughness parameter. The model is able to capture the evolving interfacial fracture energy during repeated welding cycles by using the measured roughness parameter, network modulus and BER activation energy. The study provides theoretical basis for the design and applications of CANs involving cyclic welding‐peeling operations. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 402–413.

Analysis of the Effect of Welding Sequence Variations on Residual Stresses and Distortions for Welding Pressure Vessels Structures at PT. Petrokimia Gresik using the Finite Element Method

The development of oil and gas industry technology has been very advanced, one of the implementation is to connect material materials to support oil and gas industry facilities. Residual stress may occur due to high temperature differences due to welding and also uneven heat distribution. This causes the material to become hard but brittle so that it may cause structural failure in the connection area. In this final project will be simulated welding pressure vessels to determine the structure of residual stresses that occur as well as the influence of Post Weld Heat Treatment on residual stress itself. The material used is aluminum and WPS data coming from the fabrication company. The simulation is divided into 2 steps: thermal and structural analysis. The value of the residual voltage of 1 to pathline pathline 3 is 189 MPa, 124.8 MPa, 100.76 MPa with distortion value of 40.43 mm. Then analyzed Post Weld Heat Treatment referring to AWS D1.1: 2000 to reduce residual stresses that occur. From the results of the Post Weld Heat Treatment value of the residual stress can be reduced significantly. After being treated Post Weld Heat Treatment with variations of temperatures of 200 C, 300 C The maximum residual voltage reduction occurs in pathline 1 to pathline 3 at 125 MPa, 93 MPa, 100 MPa.

Grain growth during ultrasonic welding of nanocrystalline alloys

The effects of ultrasonic welding on the structure of nanocrystalline feedstock were investigated using nanostructured Ag-W as a model system. Transmission electron microscopy of welded Ag-W foils revealed extensive grain growth as well as second phase precipitation along the weld interface. These structural changes were related to the ultrasonic welding process variables by combining classical models of frictional heating and grain growth. Process diagrams showing the extent of grain growth under a given set of welding conditions were computed and used to identify combinations of weld pressure and weld time that give strong bonds while still preserving the structure of the feedstock.

Ultrasonic spot welding of Al–Cu dissimilar metals: a study on parametric influence and thermo-mechanical simulation

Ultrasonic welding is becoming an essential technique for joining of thin and dissimilar materials in battery electric vehicle manufacturing because of consumption of less power, unmatched weld quality, high production rate, excellent efficiency, etc. The process control parameters in welding play a vital role in getting a good quality weld. In this study, AA1100 aluminum and UNS C10100 copper are utilized for experimentation by controlling three input parameters such as weld pressure, weld time, and vibration amplitude. The effects of these control parameters on the responses like tensile shear and T-peel failure loads of joints with microstructures are revealed. Furthermore, a three-dimensional thermo-mechanical finite element (FE) model with the relevant welding mechanics is proposed for this dissimilar material combination to predict the temperature distribution in its interface, sonotrode, and anvil. The simulation results are validated by comparing the experimental temperature values, and they are showing good agreement with each other. It provides a significant insight of thermal softening phenomenon in ultrasonic welding process and demonstrates the relationship between physical attributes and the interface temperature.

Water resistance of natural joint of spruce produced by linear friction welding without any treatment

ABSTRACTThis research work showed that spruce wood can be butt welded in a short time end-grain to-end-grain without any treatment. Wood welding has already been shown to be well adapted to the manufacture of wood structures of larger dimensions. When pressure increased, the welded material formed is of higher density and consequently the water resistance improved. The welded spruce samples present a much improved water resistance when the welding pressure was increased from 2.75 MPa to 3.75 MPa for the same welding time of 6 s. The welded interphase in end-grain-to-end-grain butt welding of spruce appears to occur by the formation of an interphase having the appearance of finger-joints. This is due to the different behaviours of the late and early wood rings of spruce during welding. This, by increasing the surface of contact, is shown to improve the water resistance of the original butt joint.

Features of Plasma-Electrolytic Coatings Formation on Metalware Surface

The paper presents the principal advantages of plasma-electrolytic coating method that characterize it as a highly promising technology. It is shown that these advantages are provided by the integrated nature of the effect, representing a combination of the main types of impacts on a surface: electrical, thermal, mechanical and chemical. This combination distinguishes the method of plasma-electrolytic treatment from many other widespread in up-to-date technology combinations composed generally of two types of impacts. It is suggested that the process of plasma-electrolytic coating is carried out by the mechanism of metal pressure welding that is confirmed by the results of tests for determining quality ratings of coatings. It is shown the thermodynamic and kinetic unity of these processes that allows plasma-electrolytic coating to be put in class of metal pressure welding processes and to consider the processes of coating by plasma-electrolytic method and pressure welding from a common methodological framework. The paper presents the results of the structure and composition studies of zinc plasma-electrolytic coatings on a strip for armoring cables of group A (GOST 3559-75). The researches were carried out using scanning electron microscopy, microroentgenspectral analysis and differential scanning calorimetry.

Reflection and Mode Conversion of Fundamental Torsional Guided Wave Mode From Lack of Bonding in Induction Pressure Welding

Interaction of fundamental torsional ultrasonic pipe guided mode T(0, 1) from defects caused by induction pressure welding (IPW) process is studied using three-dimensional (3D) finite element (FE) analysis validated by experiments. Defects are assumed as cross-sectional notches along the weld bond-line, and both surface-breaking and embedded features are considered. Results show that T(0, 1) mode reflection from weld defects is strongly influenced by features of the weld itself. However, with supplementary results such as the mode-converted flexural F(1, 3) and F(1, 2) modes and circumferential variation of T(0, 1) reflection, there is potential for an effective screening solution.

Fabrication of ultra-thin copper foil pressure welding using FSW equipment

Experimental investigations were carried out using a numerically controlled milling machine to weld ultra-thin copper foils (20μm and 50μm thickness).Welds were analyzed by optical microscopy, scanning electron microscopy (EDS), tensile shear tests and micro-hardness. The ultimate maximum shear-load could be achieved up to 56N with the rotation speed of 800rpm and the traveling speed of 25mm/min, which should be attributed to optimum heat and pressure. The interface bonding mechanism was also expounded and three main influence factors were analyzed in detail respectively.

Pressure welding of dissimilar creep-resisting alloys and simulation of the effect of the geometrical parameters of the specimen on the localisation of plastic deformation in the pressure welding zone

Computer modelling is used to investigate the possibilities of increasing the quality of welded joints in pressure welding of dissimilar creep-resisting materials in the presence of a relief on one of the welded surfaces. It is shown that the quality of welded joints depends on the geometrical parameters of the welded specimen.