Loading...
Search for:
steel-sheet
0.012 seconds
Total 38 records
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...
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 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...
The influence of fiber/matrix debonding on inelastic micro-mechanical behavior of cross-ply IMC composites
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 4 , 2010 , Pages 197-222 ; 9780791849187 (ISBN) ; Abedian, A ; Sharif University of Technology
2010
Abstract
In this study the effect of stress field on delamination and fiber/ matrix debonding in laminated composite panels is investigated from the micro-mechanical point of view by means of 3-D Finite Element Models. Specifically, the behavior of two-layer cross-ply symmetric laminates made up of SCS-6/Ti-24Al-11Nb Intermetallic Matrix Composite (IMC) during cooling from the processing temperature is studied. The results show that large plastic strains occur at the fiber/ matrix interface at the fiber end on the laminate free edge which may eventually extend to the interface of the layers of the laminate inflicting delamination damage. This phenomenon is more serious at the corner areas of the...
Determination of critical strain for initiation of dynamic recrystallization
, Article Materials and Design ; Volume 31, Issue 3 , 2010 , Pages 1360-1364 ; 02641275 (ISSN) ; Sharif University of Technology
2010
Abstract
Using the work hardening rate-strain curves, an effective mathematical model has been developed to predict the stress-strain curves of alloy steel during hot deformation up to the peak stress regardless of the level of the strain, weather smaller or larger than the critical strain. This model is expressed in terms of peak stress, peak strain and one temperature-sensitive parameter, S. In addition, one new model, which is a function of peak strain, was proposed to predict the critical strain for the initiation of dynamic recrystallization using the second derivative of work hardening rate with respect to stress. Besides the theoretical study, the analysis is used to determine the...
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...
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...
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...
Investigation on the bond strength of Al-1100/St-12 roll bonded sheets, optimization and characterization
, Article Materials and Design ; Volume 32, Issue 6 , 2011 , Pages 3143-3149 ; 02641275 (ISSN) ; Kokabi, A. H ; Seyed Reihani, S. M ; Sharif University of Technology
Abstract
Al-1100/St-12 aluminum clad steel sheets were produced using roll bonding process at different reductions in thickness and with various supplemental annealing treatments. Experiments were conducted by applying the Taguchi method to obtain optimum condition for maximizing the joint strength. The joint strengths of the bi-layer sheets were evaluated by peel test. The Al/Fe intermetallic phases at the joint interface and the peeled surfaces were examined using scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) and Vickers microhardness test were performed to characterize the intermetallic compounds. The results indicate that at the optimum condition of 0.50 reduction in...
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...
Effect of finishing temperature on mechanical properties of a Nb-microalloyed steel sheet
, Article Advanced Materials Research, 17 September 2010 through 19 September 2010 ; Volume 129-131 , 2010 , Pages 1022-1028 ; 10226680 (ISSN) ; 9780878492435 (ISBN) ; Akbarzadeh, A ; Abedi, A ; Sharif University of Technology
Abstract
Thermo mechanical processing and controlled rolling of microalloyed steel sheets are affected by several factors. In this investigation, finishing temperature of rolling which is considered as the most effective parameters on the final mechanical properties of hot rolled products has been studied. For this purpose, three different finishing temperatures of 950, 900 and 850 °C below the non-recrystallization temperature and one temperature of 800 °C in the intercritical range were chosen. It is observed that decreasing the finishing temperature causes increase of strength and decrease of total elongation. This is accompanied by more grain refinement of microstructure and the morphology was...
Relationship between failure behaviour and weld fusion zone attributes of austenitic stainless steel resistance spot welds
, Article Materials Science and Technology ; Volume 24, Issue 12 , 2008 , Pages 1506-1512 ; 02670836 (ISSN) ; Pouranvari, M ; Sanaee, M. H ; Abedi, A ; Abootalebi, H ; Goodarzi, M ; Sharif University of Technology
2008
Abstract
Resistance spot welding was used to join austenitic stainless steel sheets. Mechanical properties of the spot welds were evaluated using tensile shear test. Mechanical behaviour was described by peak load, failure energy and failure mode. The relationship between weld fusion zone attributes and failure behaviour was studied. Generally, it was observed that increasing fusion zone size is accompanied by an increase in load carrying capacity and energy absorption capability. However, when expulsion occurs, despite almost constant weld fusion zone size, energy absorption capability reduces significantly due to increase in electrode indentation depth. Considering the failure location and failure...
Effects of cold rolling on the microstructure and mechanical properties of Fe-Ni-Mn-Mo-Ti-Cr maraging steels
, Article International Journal of Minerals, Metallurgy and Materials ; Volume 18, Issue 5 , 2011 , Pages 557-561 ; 16744799 (ISSN) ; Nedjad, S. H ; Behnam, M. M. J ; Sharif University of Technology
Abstract
Effects of cold rolling on the microstructure and mechanical properties of Fe-Ni-Mn-Mo-Ti-Cr maraging steels were studied. To investigate the microstructure and mechanical properties, optical microscopy, scanning electron microscopy, X-ray diffraction, tensile test, and hardness test were used. The results show that the solution-annealing treatment in the cold-rolled steel redounds to the formation of submicrocrystalline Fe2 (Mo, Ti) Laves phase particles, which are stable at high temperatures. These secondary Laves phase particles prevent from recrystallization at high temperatures and correspond to semi-brittle fracture in the subsequent aging treatment
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....
Mechanical properties and microstructure of resistance spot welded severely deformed low carbon steel
, Article Materials Science and Engineering A ; Volume 529, Issue 1 , 2011 , Pages 237-245 ; 09215093 (ISSN) ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
2011
Abstract
The welding of nanostructured low carbon steel sheets produced by severe plastic deformation (SPD) has been considered in the present paper. Constrained groove pressing (CGP) method is used for imposing the severe plastic deformation to the steel sheets as a large pre-strain. The SPDed sheets are joined using resistance spot welding (RSW) process. The results show that severe plastic deformation can effectively increase the electrical resistivity of steel sheets; therefore it can affect the microstructure and mechanical properties of spot welds. Microstructure and mechanical properties of fusion zone, heat affected zone (HAZ), recrystallized zone and base metal of SPDed sheets are...
The annealing phenomena and thermal stability of severely deformed steel sheet
, Article Materials Science and Engineering A ; Volume 528, Issue 15 , June , 2011 , Pages 5212-5218 ; 09215093 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2011
Abstract
However, there are many works on annealing process of SPDed non-ferrous metals, there are limit works on annealing process of SPDed low carbon steel. Therefore, in this study the annealing responses after constrained groove pressing (CGP) of low carbon steel sheets have been investigated. The sheets are subjected to severe plastic deformation at room temperature by CGP method up to three passes. Nano-structured low carbon steel sheets produced by severe plastic deformation are annealed at temperature range of 100-600 °C for 20. min. The changes of their microstructures after deformation and annealing are studied by optical microscopy. The effects of large strain and annealing temperature on...
The effect of constrained groove pressing on grain size, dislocation density and electrical resistivity of low carbon steel
, Article Materials and Design ; Volume 32, Issue 6 , 2011 , Pages 3280-3286 ; 02641275 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
Abstract
In this research, constrained groove pressing (CGP) technique is used for imposing severe plastic deformation (SPD) on the low carbon steel sheets. Using transmission electron microscopy (TEM), X-ray diffraction (XRD) and optical microscopy, the microstructural characteristics of produced sheets are investigated. The results show that CGP process can effectively refine the coarse-grained structure to an ultrafine grain range. Dislocation densities of the ultrafine grained low carbon steel sheets are quantitatively calculated and it is found that the CGP can effectively enhance the dislocation density of the sheets. Measurements of their electrical resistivity values show that microstructure...
Effect of post annealing treatment on nano-structured low carbon steel sheets processed by constrained groove pressing
, Article Materials Science Forum, 21 March 2011 through 25 March 2011 ; Volume 667-669 , March , 2011 , Pages 1009-1014 ; 02555476 (ISSN) ; 9783037850077 (ISBN) ; Kazeminezhad, M ; Azarnush, M ; Miran, S. H ; National Natural Science Foundation of ; The Ministry of Science and Technology of China; Chinese Academy of Sciences, Institute of Metal Research; Baoshan Iron and Steel Co., Ltd ; Sharif University of Technology
2011
Abstract
There are many works on annealing process of SPDed bulk metals but there are limited works on annealing process of SPDed sheets. Therefore, in this study the annealing response after constrained groove pressing (CGP) of low carbon steel sheets has been investigated. These sheets are subjected to severe plastic deformation at room temperature by CGP method up to three passes. Nano-structured low carbon steel sheets produced by severe plastic deformation are annealed at temperature range of 100 to 600 °C for 20 min. The microstructural changes after deformation and annealing are studied by optical microscopy. The effects of CGP strain and annealing temperature on microstructure, strength and...