Showing 11 results for Resistance Spot Welding
Dr M. Safari, Dr H. Mostaan,
Volume 1, Issue 1 (1-2016)
Abstract
Weldability of high carbon steels due to the high percentage of carbon and consequently formation of martensitic structure is very poor. In this research, resistance spot welding of eutectoid high carbon steel 1075 is experimentally and numerically investigated from various points of view. The effect of welding current as one of the most effective parameters on failure mode, mechanical properties and nugget size diameter in resistance spot welding is analyzed with experimental tests and numerical simulations. The results show that with increase of welding current, the diameter of nugget size is increased and consequently the failure mode changes from interfacial mode to pull out mode.
M. Safari, H. Mostaan,
Volume 2, Issue 2 (11-2016)
Abstract
In this paper, resistance spot welding process of AISI 201 stainless steel is studied experimentally. For this purpose, effect of welding current on quality of weld is investigated and relationships between welding current and fusion zone characteristics are examined. For determining mechanical properties such as maximum load and fracture mode, tensile - shear test of spot welds is performed. Hardness and microstructural examinations are performed for study the influence of welding current on characteristics of welded joints. The results show that strength of resistance spot welds of AISI 201 stainless steel is increased with increase in welding current. Transition of fracture mode from interfacial to pullout and then pullout with tearing of sheet mode during tensile-shear tests of AISI 201 spot welds is investigated through experimental and theoretical approaches. It is concluded from results that increasing in welding current leads to change in fracture mode from interfacial to pullout mode due to increase in fusion zone size (weld nugget size). Also, it is observed that increasing in fusion zone size is accompanied by an increase in load carrying capacity of resistance spot welds. The minimum required fusion zone size to ensure pullout fracture mode is estimated using an analytical model.
V. Zohoori-Shoar, F. Karimzadeh, A. Eslami,
Volume 3, Issue 1 (8-2017)
Abstract
In this study, The Al 6061 alloy sheets were produced by Cryorolling process and then were welded by resistance spot welding method. In this regard, the solution treated Al 6061 alloy cryorolled subsequently up to 90% reduction in thickness to produce nanostructure alloy. The cryorolled sheets were then subjected to aging treatment (130˚C-30h) in order to obtain simultaneous strength and ductility. Tensile strength of 370 MPa, hardness of 135 HV, and ductility of 11 % was obtained for the nanostructured Aluminum sheets. The Cryorolled samples were then resistance spot welded with different welding parameters, including welding current 50 to 100 kA, electrode force of 2.8 kN, and welding time of 0.1 s. The most tensile shear peak load of weld spot of nanostructured samples was 5580 N. The results for different welded samples showed that the nanostructured ones, have higher weld strength when compared with 6061-T6 Aluminum alloy samples with common grain size.
En Payam Gheysari, Dr Fathallah Karimzadeh, Dr Ahmad Rezaeian, En Amin Shahsavari,
Volume 3, Issue 2 (1-2018)
Abstract
In this research in order to improve the mechanical properties of Aluminium alloy 2024, nanostructure Aluminum sheets were first produced by Cryorolling process and then was welded by resistance spot welding method. For this purpose, the samples solution treated at 495˚C for 55 minute and subsequently cryorolled up to 85% reduction in thickness. For obtaining simultaneous strength and ductility, the cryorolled sheets were then subjected to aged. In this regard the produced samples were then resistance spot welded with different welding parameters, including welding current 60 to 105 KA, electrode force of 3 KN, and welding time of 0.1 s. The highest tensile shear peak load was obtained through welding with 95 KA current.
M. Atashparva, M. Hamedi,
Volume 3, Issue 2 (1-2018)
Abstract
Nowadays, due to the need for miniaturization, small scale resistance spot welding is of interest. The key factor that determines the nugget size is contact resistance. In this paper a new equation is provided to calculate the electrical contact resistance. The model can predict the high temperature contours and the nugget configuration efficiently. Also, a set-up was constructed to verify the model and investigate the effects of parameters on the mechanical properties of Hastelloy X welded joints. DOE analysis is done to recognize the effect of parameters on the nugget diameter, maximum load, and nugget height. It was concluded that the size of the nugget enlarges by increasing welding current and time. The nugget diameter decreases with increase of force.
H. Mostaan, M. Safari, A. Sonboli, M. Haddadi, A. Taherkhani,
Volume 4, Issue 1 (8-2018)
Abstract
In this paper, numerical and empirical investigations of the effect of AISI 347 stainless steel interlayer on the microstructure, mechanical properties and fracture mode of AISI 321 stainless steel resistance spot welds have been conducted. For this purpose, two types of joints, the first free from inter layer and the second contains interlayer with 0.05 mm thickness as well as difference currents and times,were evaluated. In order to examine the mechanical properties including maximum force and tensile mode, tensile – shear test of the spot welds was done. The obtained results indicated that an increase in the welding time and current resulted in a change in fracture mode from interfacial to peripheral owing to an increase in fusion zone volume. The change in the chemical composition because of the presence of interlayer and an increase in cooling rate caused the formation of different phases as well as observation of the dispersed Martensite phase in fusion zone.
R. Ashiri, M. Shamanian, H. R. Salimijazi, Y. Park, M. R. Salmani,
Volume 6, Issue 2 (12-2020)
Abstract
Nowadays, the use of advanced high strength steels (AHSSs) in body-in-white is one of the hot applied strategies which is followed by the most of the automakers. The study of weldability and weld challenges facing these steels in resistance spot welding process as the most widely used process in the assembly lines of the automotive industry is essential to use the outstanding mechanical responses of AHSSs. This study can result in improvement of mechanical performance of the resistance spot welds of AHSSs. Our results indicate that AHSSs experiences different welding challenges which this work aims to study them by discussing their causes, mechanisms involved and potential ways to address them.
Mehdi Safari, Amir Hossein Rabiee, Jalal Joudaki,
Volume 7, Issue 1 (8-2021)
Abstract
Resistance Spot Welding (RSW) is one of the effective manufacturing processes used widely for joining sheet metals. Prediction of weld strength of welded samples has great importance in manufacturing and different methods are used by researchers to find the fracture force. In this article, the Adaptive Neuro-Fuzzy Inference System (ANFIS) is utilized for prediction of joint strength in welded samples by RSW. A design of experiments (DOE) is prepared according to effective process parameters includes welding current, welding cycle, cooling cycle and electrode force. The sheet metal samples prepared from AISI 1075 carbon steel. Tensile test specimens are prepared and the tensile-shear strength of welded samples are measured. A model is developed according to ANFIS and trained according to teaching-learning based optimization algorithm. 70 % of test data used for network train and the remained 30 % used for access the accuracy of trained network. The accuracy of the trained network was assessed and the results show that the trained network can predict the joint strength with high accuracy. The determination factor (R2) and mean absolute percentage error (MAPE) are 0.99 and 0.48 % for trained data and 0.95 and 6.2% for test data.
H. Sabet, R. Tahavori, A. Alimoradi,
Volume 7, Issue 2 (1-2022)
Abstract
Effect of Interlayer Composition on the Microstructure and Mechanical Properties of 1050 Aluminium to St14 Carbon Steel Joint Via Resistance Spot Welding Method.
Hossein Abedi Chermahini, Mohammad Mahdi Piran, Ali Akbar Esmaeili Chamgordani, Masoud Atapour,
Volume 9, Issue 2 (8-2024)
Abstract
In this research, the mechanical properties and microstructure of L316 grade stainless steel sheets welded using the resistance spot welding method with a copper interlayer were investigated. In this regard, two types Connection were considered: one without the interlayer and the other with the copper interlayer, connected at different currents. To select the optimal current for both types of connections, tensile tests were initially conducted. Following that, microstructural examinations, microhardness tests, elemental evaluations, and failure mode analyses were performed on the optimized samples. according to the results obtained, increasing the electric current raised the input heat in the weld pool to an appropriate level, improving the microstructural and mechanical properties of the weld region. Additionally, due to the optimal electric current in both samples "with and without" the interlayer, both samples experienced interfacial failure, indicating high strength at their joint and weld points. Changes in chemical composition across different weld areas were minimal, and element distribution was reported to be uniform throughout all regions. The highest hardness was observed from the base metal towards the center of the weld in the order of weld area > base metal > heat-affected zone, which corresponded with results from microstructural examinations.
A. R. Nazari , A. Taherizadeh, M. Atapour,
Volume 10, Issue 1 (6-2024)
Abstract
In this study, the microstructure and mechanical properties of dissimilar resistance spot welding of AISI 430 steel and S500 MC steel were investigated. To carry out this research, Taguchi's L9 array was used to determine the number of samples and determine the range of variables of each sample, and after welding the samples and performing the shear tensile test, the sample with the highest tensile shear strength (13740 N) and the highest amount of fracture energy (102160 Joules), was considered as the best example; Also, the variables of this sample, i.e., welding current of 12 kW, welding time of 12 cycles, and electrode force of 3 kN, had the highest signal-to-noise values, and these values were chosen among the best range of variables among the proposed variables. Then, a microhardness test was performed on the welded sample with the above variables, and microstructural studies were performed by optical microscope and scanning electron microscope. The hardness of the weld zone was observed to be about 400 Vickers, and the microstructure of the weld metal consisted of ferrite, martensite, and Widmannstatten ferrite.
