Loading...
Search for:
steel-sheet
0.011 seconds
Total 38 records
Theoretical and Experimental Investigation of Cold Roll Welding for Production of Aluminum Clad Steel Sheet
, Ph.D. Dissertation Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
Aluminum coated steel sheet is an excellent composite material in which; the strength and economy of steel and durability of aluminum are combined. This material is produced by several methods. However, there are two main technologies to produce aluminized steel sheets: 1) the hot dip method and 2) the aluminum clad method (cold roll welding process). The hot dip method is most widely used for producing the aluminum coated steel. The aluminum coated steel sheet manufactured by this method is believed to be inferior to an aluminum sheet with respect to surface appearance, corrosion resistance and formability of the coated metal. Consequently, the aluminum clad steel method is one of the most...
Investigation on Pulsed TIG Lap Welding of Al-5052 Sheet to Al-1050 Clad St-12 Sheet
, M.Sc. Thesis Sharif University of Technology ; Movahhedi, Mojtaba (Supervisor)
Abstract
In this study, Al-5052 aluminium alloy sheet was lap joined to aluminium clad steel sheet using pulsed gas tungsten arc welding and Al-Si filler metal. Effect of heat-input, thickness of clad layer and frequency were investigated on the formation of intermetallic reaction layer, microstructure of the weld seam and shear strength of the joints are explored. Stress analysis in weld is also used in order to justify the fracture location in the welds the microstructure and shear-tensile strength of the welds (joining with A1-1050 clad layer with two thickness of 350 μm and 1000 μm). Before welding, aluminum clad steel sheets were produced by roll bonding and 450 °C annealing temperature and 90...
Experimental Investigation of the Behavior of Squat Composite Corrugated Shear Walls Under In-Plain Shear
,
M.Sc. Thesis
Sharif University of Technology
;
Khalu, Alireza
(Supervisor)
Abstract
The new lateral load resisting system introduced in this dissertation is a kind of squat composite shear wall consisting of a concrete core as filler and two steel corrugated sheets as cover. Reinforced bars are not used in this kind of construction. Load resisting process of the walls is provided by 3 factors: concrete core, steel corrugated covers on both sides of the central core and shear-friction interaction between the core and covers. There is not any specific formula for their design because of their novelty and few researches on this kind of walls and absence of code provisions. In this project, squat composite walls were constructed with dimensions of 106.8×90 (cm2) from corrugated...
Experimental and Numerical study on Resistance Spot Welding of Aluminum to Aluminum Clad Steel Sheet
, M.Sc. Thesis Sharif University of Technology ; Movahedi, Mojtaba (Supervisor) ; Serajzadeh, Siamak (Supervisor)
Abstract
Resistance spot welding is one of the types of sheet metal joining processes used in many industries, such as automotive, home appliances, and aviation. In the direct welding of aluminum to steel, brittle intermetallic compounds are formed, which is necessary to control the thickness of these intermetallic compounds to improve welding properties. Using an aluminum-clad layer can effectively reduce the thickness of intermetallic compounds by reducing the heat generation at the steel-aluminum interface. This research aims to investigate experimentally and theoretically the welding of aluminum-clad steel sheet to Al-Mg aluminum sheet by resistance spot welding process with finite element method...
A study on sheet formability by a stretch-forming process using assumed strain FEM
, Article Journal of Engineering Mathematics ; Volume 65, Issue 4 , 2009 , Pages 311-324 ; 00220833 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
Springer Netherlands
2009
Abstract
The effects of sheet thickness and frictional condition between the punch and sheet on formability is predicted and compared with the experimental results of the Erichsen test as a stretch-forming process. The material and geometrical nonlinearity are considered. A hypoelastic-plastic model is used and strain-field stabilization is taken into account using the Assumed Strain Finite-Element Method. By considering the contact problem and applying the nonlinear finite-element method, the force and dome height for aluminum and steel sheets are computed and compared with the experimental results. The Oyane criterion is used to access the formability of the sheet. A good agreement was found...
Effect of dwell time on joint interface microstructure and strength of dissimilar friction stir spot-welded al-5083 and st-12 alloy sheets
, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 48, Issue 4 , 2017 , Pages 1744-1758 ; 10735623 (ISSN) ; Movahedi, M ; Kokabi, A. H ; Najafi, H ; Sharif University of Technology
Springer Boston
2017
Abstract
Joining of Al-5083 alloy sheet to St-12 steel sheet was performed using a new friction stir spot welding (FSSW) technique in which the tool pin tip did not enter lower steel sheet. Effect of dwell time on the microstructure and mechanical properties of the joints was studied by various methods including microhardness measurements, shear test, stereo and light microscopy as well as scanning and transmission electron microscopy (SEM and TEM). Results indicated that compared to the conventional FSSW process, stronger joints can be achieved by this FSSW technique. Cross-sectional observation of the failed specimens indicated the occurrence of final fracture from the circumference of the tool pin...
A micro mechanical study on tensile behavior of steel sheets with spheroidal cementite using crystal plasticity finite element method
, Article Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications ; Volume 236, Issue 12 , 2022 , Pages 2357-2371 ; 14644207 (ISSN) ; Assempour, A ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
In this research, we investigate the effects of various microstructural features on the behavior of spherical steel sheets, using the crystal plasticity finite element method. The cementite phase ratio, the grain sizes of ferrite and cementite, and the percentage of residual pearlite in the steel structure due to incomplete annealing are the major microstructural parameters studied in this work. A grain generator software has been developed to generate hexagonal ferrite grains as well as circular cementite particles distributed in the ferrite matrix. We use a hard coating with special properties as an intermediate layer around the cementite grains to simulate the contact between ferrite...
Numerical study of shunting effect in three-steel sheets resistance spot welding
, Article International Journal of Engineering, Transactions B: Applications ; Volume 35, Issue 2 , 2022 , Pages 406-416 ; 1728144X (ISSN) ; Farrahi, G. H ; Minaei, M ; Masajedi, R ; Gholamnia, M ; Shademani, M ; Sharif University of Technology
Materials and Energy Research Center
2022
Abstract
The main purpose of the present research is to investigate the shunting phenomenon in a three-sheet RSW joint usingfinite element simulation. To this end, a three-sheet resistance spot weldingjoint was simulatedas an electrical-thermal-mechanical couplingproblem.Tovalidate the presentedsimulation, the finite element results were compared with the experimental results, including nugget size and geometric shapein theresistance spot weldingjoint.Afterwards, the multi-spot welds of three-sheet low carbon steels with the same thicknesses were analyzed considering the sequential distance of 45 mm. Various techniques, includingnewspot-welddiametermeasurement, electrical current density, electrical...
Metallurgical characteristics and failure mode transition for dissimilar resistance spot welds between ultra-fine grained and coarse-grained low carbon steel sheets
, Article Materials Science and Engineering A ; Volume 637 , 2015 , Pages 12-22 ; 09215093 (ISSN) ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
We studied the microstructure and mechanical characteristics of spot welded specimens, fabricated from low carbon steel sheets with different microstructures. Both ultra-fine grained (UFG) steel sheet and coarse grained (CG) steel sheet were used. The refined microstructure of the UFG steel has been produced by severe plastic deformation (SPD) using the constrained groove pressing (CGP) method. The grain size of the base metals was approximately 260. nm and 30. μm in diameter, respectively, in the UFG and CG steels. Examining the microstructure of a cross section cut through the spot weld reveals a similar grain size and phase distribution in the nugget on both the sides of the initial...
Investigation of CFS shear walls with one and two-sided steel sheeting
, Article Journal of Constructional Steel Research ; Volume 122 , 2016 , Pages 292-307 ; 0143974X (ISSN) ; Alizadeh, S ; Hadidi, S ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this study six Cold-Formed Steel shear wall (CFS) with one and two side steel sheeting are tested under reversed cyclic loading. Besides, thirteen numerical models are simulated, using nonlinear finite element method, and analyzed under monotonic pushover loading. The studied parameters are the comparison of one and two side steel sheeting, the nominal thickness of steel sheet and boundary elements, and height to width aspect ratios of the wall. The performance of tested specimens is investigated in terms of lateral load-story drift response, failure modes and ultimate strength of shear walls. Based on AISI S213 the available strength of two-sided steel-sheathed walls is cumulative but...
Welding of Al-Mg aluminum alloy to aluminum clad steel sheet using pulsed gas tungsten arc process
, Article Journal of Manufacturing Processes ; Volume 31 , 2018 , Pages 494-501 ; 15266125 (ISSN) ; Movahedi, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Al-Mg aluminum alloy was lap joined to aluminum clad steel sheet using pulsed gas tungsten arc welding process and Al-Si filler metal. The effects of the welding heat-input were investigated on the joint microstructure and mechanical properties. Weld metal microstructure, formation of intermetallic compounds (IMCs) at the joint interface and the fracture locations were studied using stereo, optical and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). The joint strength of the welds was evaluated by shear-tensile test. The results showed that presence of a thin aluminum clad layer with 350 μm thickness drastically decreased the Al-Fe intermetallic...
Resistance spot welding of aluminum to aluminum clad steel sheet: experimental and theoretical analysis
, Article Journal of Manufacturing Processes ; Volume 58 , 2020 , Pages 429-435 ; Movahedi, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In order to increase the cross-tension to the tensile-shear peak load ratio, aluminum clad steel sheet produced by roll bonding, was used for resistance spot welding to Al-Mg aluminum alloy. The results showed that the weld nugget formed between the aluminum clad layer and Al-Mg base sheet was the load bearing area. Presence of the metallurgical bond between the steel sheet and the aluminum clad layer led to the formation of the Al/Fe intermetallic compound with the thickness less than ∼3.5 μm. This narrow intermetallic layer did not play a detrimental role in the weld strength and therefore, the cross-tension to the tensile-shear peak load ratio reached up to ∼0.5 at the maximum...
Weld orientation effects on the formability of tailor welded thin steel sheets
, Article Thin-Walled Structures ; Volume 149 , April , 2020 ; Darabi, R ; Ghabussi, A ; Habibi, M ; Foong, L. K ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Tailored welded blanks (TWBs) technology can give the important possibilities to obtain components in the automobile industry. Friction stir welding (FSW) is a joining approach, which can adhere parts well with desired properties in weld zone. In this article, the main aim is investigation the effect of weld zone orientation on forming limit diagram (FLD) of the TWBs using experimental and finite element model. Three TWBs are produced FSW with three different orientations of weld zones including 00, 450 and 900 against major stress direction. The microstructure of the weld zones is divided and then observed via metallography procedures. Tensile tests are carried out to determine the...
The effect of cold-rolling prior to the inter-critical heat treatment on microstructure and mechanical properties of 4340 steel with ferrite – Martensite microstructure
, Article Materials Science and Engineering A ; Volume 830 , 2022 ; 09215093 (ISSN) ; Ekrami, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This study investigates the effect of cold rolling prior to inter-critical annealing on microstructure and mechanical properties of ferrite-martensite dual phase steel. Samples were heated to 850 °C for 1 h followed by oil quenching, then the steel sheet were cold rolled by 0%,10%,15% and 20% reduction in thickness. The inter-critical annealing treatment (750 °C, 120min) was performed to generate a ferrite-martensite microstructure. Microstructural studies showed that increasing the applied cold rolling, leading to increase in volume fraction of martensite and decrease in ferrite grain size. Mechanical properties of dual phase steel were measured by tensile, impact and hardness tests....
Effect of electropulsing on microstructure and hardness of cold-rolled low carbon steel
, Article Journal of Materials Research and Technology ; Volume 8, Issue 3 , 2019 , Pages 3114-3125 ; 22387854 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
Elsevier Editora Ltda
2019
Abstract
The application of electropulsing treatment (EPT) is studied on the microstructure and hardness of cold-rolled low carbon steel. The effects of electrical pulses on the grain refinement, precipitate size evolution and hardness are investigated. It is found that applying electrical pulse decreases the grain and precipitate size and increases the hardness in the early stages of electropulsing, but the grain and precipitate size is increased and the hardness is decreased by continuing electropulsing. Also, the effect of electropulsing treatment variables as well as treated time and number of periods are discussed. It is demonstrated that increasing treated time can accelerate achieving maximum...
Differential scanning calorimetry study of constrained groove pressed low carbon steel: Recovery, recrystallisation and ferrite to austenite phase transformation
, Article Materials Science and Technology (United Kingdom) ; Vol. 30, issue. 7 , 2014 , pp. 765-773 ; ISSN: 02670836 ; Kazeminezhad, M ; Sharif University of Technology
Abstract
Low carbon steel sheets are subjected to severe plastic deformation (SPD) via constrained groove pressing (CGP) up to five passes. As a result of this process, strain magnitude up to 5?8 is imposed to the sheets, which leads to grain size of 225 nm. These nanostructured steel sheets, due to their high dislocation density and ultrafine microstructure, are very sensitive to heating. In the present study, recovery, recrystallisation and ferrite to austenite phase transformation phenomena for the SPD steel are investigated using differential scanning calorimetry method. The results show that with increasing the strain in steel sheets, the deformed stored energy (released through recovery and...
Resistance spot welding of ultra-fine grained steel sheets produced by constrained groove pressing: Optimization and characterization
, Article Materials Characterization ; Volume 69 , 2012 , Pages 71-83 ; 10445803 (ISSN) ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
2012
Abstract
Constrained groove pressing as a severe plastic deformation method is utilized to produce ultra-fine grained low carbon steel sheets. The ultra-fine grained sheets are joined via resistance spot welding process and the characteristics of spot welds are investigated. Resistance spot welding process is optimized for welding of the sheets with different severe deformations and their results are compared with those of as-received samples. The effects of failure mode and expulsion on the performance of ultra-fine grained sheet spot welds have been investigated in the present paper and the welding current and time of resistance spot welding process according to these subjects are optimized....
Investigation on friction stir lap welding of aluminium to aluminium clad steel sheets
, Article Science and Technology of Welding and Joining ; Volume 17, Issue 3 , 2012 , Pages 231-236 ; 13621718 (ISSN) ; Kokabi, A. H ; Seyed Reihani, S. M ; Sharif University of Technology
2012
Abstract
In this work, the feasibility of friction stir lap welding an aluminium alloy (Al-5083) to the aluminium clad steel sheet was studied. The welded joints were characterised by various methods including shear-tensile test and optical microscopy and scanning electron microscopy. The results indicated that sound and defect free joints were obtained. The fracture loads of the samples reached up to 94% compared with that of the steel base metal. Moreover, the joint strength linearly increased with the decrease in thickness of the aluminium layer roll bonded on the steel sheet. It was also shown that welding rotation and travel speed variation did not considerably impact the fracture loads in the...
Forming limit diagrams of ground St14 steel sheets with different thicknesses
, Article SAE International Journal of Materials and Manufacturing ; Volume 5, Issue 1 , 2012 , Pages 60-64 ; 19463979 (ISSN) ; Ghazanfari, A ; Abrinia, K ; Assempour, A ; Sharif University of Technology
2012
Abstract
The influence of sheet thickness on sheet metal forming limits is a controversial issue; while some investigations indicate the considerable influence of thickness on forming limit diagrams (FLDs), others suggest that it is of negligible importance. In the present work, it has been demonstrated that if the thickness-reduction process is chosen so as not to alter the micro structure of the material, the forming limits do not change with variations of thickness. A material which has extensive usage in sheet metal forming processes of automotive industry (St14) has been provided. The initial thickness of the sheet is 1.5mm and using grinding process (which does not alter the microstructure) the...
The modeling and process analysis of resistance spot welding on galvanized steel sheets used in car body manufacturing
, Article Materials and Design ; Volume 34 , February , 2012 , Pages 759-767 ; 02641275 (ISSN) ; Kolahan, F ; Kokabi, A. H ; Sharif University of Technology
Abstract
In this study, the resistance spot welding (RSW) process of the galvanized interstitial free (IF) steel sheets and galvanized bake hardenable (BH) steel sheets, used in the manufacturing of car bodies, has been modeled and optimized. The quality measure of a resistance spot welding joint is estimated from the tensile-shear strength. Furthermore, four important process parameters, namely welding current (WC), welding time (WT), electrode force (EF), and holding time (HT) are considered as the factors influencing the quality of the joints. In order to develop an accurate relationship between the process inputs (4-component vectors) and the response output (tensile-shears strength) at first a...