Theoretical Justification of the Longitudinal Rolling Method of the Thick Sheets by the Severe Shear Deformation

2020 ◽  
Vol 299 ◽  
pp. 617-621
Author(s):  
Danis Nukhov ◽  
Andrey O. Tolkushkin
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Metal Forming ◽  
Large Strain ◽  
Metal Flow ◽  
Coarse Grained ◽  
Theoretical Justification ◽  
Longitudinal Rolling ◽  
Steel Sheets ◽  
Rolling Method

Severe plastic deformation (SPD) methods are based on obtaining materials with a grain size of about 100 nm by means of large strain. The SPD processes provide conditions for non-monotonic deformation of the billetsб due to the redistribution of metal macro-flows during shear or alternating strain. Numerous studies have proved the possibility of obtaining high total strain degree for a single SPD cycle. Traditional metal forming processes, such as rolling, implement monotonic deformation behaviorб due to one directional metal flow. In the process of longitudinal rolling, a banded coarse-grained structure with uneven distribution of properties in the volume of the processed metal is observed. The idea of ensuring the SPD in the process of longitudinal rolling of steel sheets is promising. The idea can be realized by the development of deformation tools and modes, which provide redistribution of metal macro-flows not only in the longitudinal but also in the transverse directions of the deformation zone.

Development of Advanced Technologies for the Production of Innovative Materials with a Submicrocrystalline Structure by Methods of Severe Plastic Deformation

2021 ◽  
Vol 410 ◽  
pp. 191-196
Author(s):  
Danis Sh. Nukhov ◽  
Andrey O. Tolkushkin
Keyword(s):  
Plastic Deformation ◽  
Metal Forming ◽  
Metal Flow ◽  
Continuous Rolling ◽  
Axial Zone ◽  
Entire Cross Section ◽  
Product Size ◽  
Advanced Technologies ◽  
Innovative Materials ◽  
Rolling Method

A promising direction for the development of steel and alloy processing processes is the intensification of plastic deformation by creating zones of localization of shear strains not only in the longitudinal but also in the transverse directions of the deformed metal flow. Intensification of alternating deformations along the entire cross-section and, especially, in the axial zone of the billet by creating new deformation schemes is an effective way to increase the physical, mechanical and functional properties of the metal with the maximum approximation of the finished product size to the original billet size. The paper shows that a promising idea is the development of new technological schemes that implement severe alternating deformation in existing metal forming processes. A continuous rolling method of wide strips is proposed, which provides severe alternating deformation with minor changes in the size of the billet. Based on this method, a scheme of continuous rolling of the strip with the intensification of plastic deformation of the metal is designed. The results of computer simulation showed that the new rolling method increases the strain uniformity in height and the value of the strain degree in the plane of symmetry of the billet.

Severe Plastic Deformation-Key Features, Methods and Application

2020 ◽  
Vol 1003 ◽  
pp. 31-36
Author(s):  
Marko Vilotic ◽  
Li Hui Lang ◽  
Sergei Alexandrov ◽  
Dragisa Vilotic
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Tensile Strength ◽  
Severe Plastic Deformation ◽  
Metal Forming ◽  
Good Corrosion Resistance ◽  
Processed Material ◽  
Key Features ◽  
Forming Methods

Compared to conventional metal forming methods, processing by severe plastic deformation is mostly used to improve the mechanical properties and not for the shaping of a product. Processed material usually has an average crystal grain size of less than a micron and as a result, the material exhibits improvements in most of the mechanical properties, such as yield and ultimate tensile strength, microhardness, sufficiently high workability, good corrosion resistance, and implant biocompatibility and others. In this paper, a brief review of the processing by severe plastic deformation was presented, including the benefits, major methods, and the application. Additionally, a brief review of two methods made by authors was made.

Unique Mechanical Properties of Nanostructured Metals

2007 ◽  
Vol 7 (11) ◽  
pp. 3765-3770 ◽  
Author(s):  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Equivalent Strain ◽  
Coarse Grained ◽  
Roll Bonding ◽  
Nanostructured Metals ◽  
Ultrafine Grained ◽  
Nanocrystalline Structures ◽  
Rolling Deformation

Recently, it becomes possible to fabricate bulk metals having ultrafine grained or nanocrystalline structures of which grain size is in nano-meter dimensions. One of the promising ways to realize bulk nanostructured metals is severe plastic deformation (SPD) above logarithmic equivalent strain of 4. We have developed an original SPD process, named Accumulative Roll Bonding (ARB) using rolling deformation in principle, and have succeeded in fabricating bulk nanostructured sheets of various kinds of metals and alloys. The ARB process and the nanostructured metals fabricated by the ARB are introduced in this paper. The nanostructured metals sometimes perform quite unique mechanical properties, that is rather surprising compared with conventionally coarse grained materials. The unique properties seem to be attributed to the characteristic structures of the nano-metals full of grain boundaries.

Ultrasonic Impact Treatment of Fine- and Coarse Grained Commercial Purity Titanium

2016 ◽  
Vol 1139 ◽  
pp. 12-15
Author(s):  
Rustam Hairullin ◽  
Anna Kozelskaya ◽  
Marina Kazachenok
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Surface Layer ◽  
Electron Backscatter Diffraction ◽  
Coarse Grained ◽  
Commercial Purity ◽  
Ultrasonic Impact Treatment ◽  
Commercial Purity Titanium ◽  
Wide Range ◽  
Purity Titanium

The grain size effect on surface morphology, microstructure and mechanical properties of commercial purity titanium specimens subjected to ultrasonic impact treatment was studied. It was found by atomic force microscope that ultrasonic impact treatment of titanium specimens resulted in surface corrugation happens due to their severe plastic deformation. The profile height of the corrugated surface depends on the grain size of specimens and varies in a wide range. The thicknesses of a modified surface layer of fine-and coarse grained titanium specimens were studied. Electron backscatter diffraction (EBSD) analysis revealed that the plastic deformation was accompanied by twin and low angle boundary formation in the surface layer of titanium specimens. The effect of ultrasonic impact treatment on the microhardness of the surface layer of the specimens under study was investigated.

INFLUENCE OF STRAIN ACCUMULATION ON MICROSTRUCTURE OF ALUMINUM 1100 IN THE TWIST EXTRUSION

2008 ◽  
Vol 22 (18n19) ◽  
pp. 2858-2865 ◽  
Author(s):  
S. A. A. AKBARI MOUSAVI ◽  
A. R. SHAHAB
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Cross Section ◽  
Strain Distribution ◽  
Metal Flow ◽  
Experimental Tests ◽  
Strain Accumulation ◽  
Twist Extrusion ◽  
Simulation Results ◽  
Metallographic Images

Nowadays, Severe Plastic Deformation (SPD) methods are at the focus of material researchers and among these methods, Twist Extrusion (TE) is one of promising ones to pave the way of commercialization. In this Investigation the magnitude of strain distribution along 4 selected paths of sample after 3 passes of Twist Extrusion were investigated by computer simulation and its influence on aluminum 1100 microstructure by experimental tests. ABAQUS 6.5 software based on FEM was applied for the former and 70 mm length samples with cross-section of 18*28 mm were exploited for the latter. According to the simulation results, corner, middle of small side, middle of long side and center of the cross-section are placed from maximum to minimum magnitude of strain respectively. Theses achievements were verified with metallographic images in aspect of metal flow and grain size as well.

Analysis and Technology in Metal Forming

1989 ◽  
Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan
Keyword(s):  
Heat Transfer ◽  
Plastic Deformation ◽  
Flow Stress ◽  
Velocity Field ◽  
Metal Forming ◽  
Metal Flow ◽  
Die Design ◽  
Flow Forming ◽  
Part Geometry ◽  
Formed Part

The design, control, and optimization of forming processes require (1) analytical knowledge regarding metal flow, stresses, and heat transfer, as well as (2) technological information related to lubrication, heating and cooling techniques, material handling, die design and manufacture, and forming equipment. The purpose of using analysis in metal forming is to investigate the mechanics of plastic deformation processes, with the following major objectives. • Establishing the kinematic relationships (shape, velocities, strain-rates, and strains) between the undeformed part (billet, blank, or preform) and the deformed part (product); i.e., predicting metal flow during the forming operation. This objective includes the prediction of temperatures and heat transfer, since these variables greatly influence local metal-flow conditions. • Establishing the limits of formability or producibility; i.e., determining whether it is possible to perform the forming operation without causing any surface or internal defects (cracks or folds) in the deforming material. • Predicting the stresses, the forces, and the energy necessary to carry out the forming operation. This information is necessary for tool design and for selecting the appropriate equipment, with adequate force and energy capabilities, to perform the forming operation. Thus, the mechanics of deformation provides the means for determining how the metal flows, how the desired geometry can be obtained by plastic deformation, and what the expected mechanical properties of the produced part are. For understanding the variables of a metal-forming process, it is best to consider the process as a system, as illustrated in Fig. 2.1 in Chap. 2. The interaction of most significant variables in metal forming are shown, in a simplified manner, in Fig. 3.1. It is seen that for a given billet or blank material and part geometry, the speed of deformation influences strain-rate and flow stress. Deformation speed, part geometry, and die temperature influence the temperature distribution in the formed part. Finally, flow stress, friction, and part geometry determine metal flow, forming load, and forming energy. In steady-state flow (kinematically), the velocity field remains unchanged, as is the case in the extrusion process; in nonsteadystate flow, the velocity field changes continuously with time, as is the case in upset forging.

Effects of Extrusion Speed on the Deformation of Copper Using ECAP Based on FEM

2015 ◽  
Vol 1088 ◽  
pp. 729-732 ◽  
Author(s):  
Chun Ling Wu ◽  
Zhong Ren Wang ◽  
Wen Zhang
Keyword(s):  
Plastic Deformation ◽  
Effective Stress ◽  
Metal Forming ◽  
Large Strain ◽  
Effective Strain ◽  
Extrusion Speed ◽  
Fine Grained ◽  
Ecap Process ◽  
Friction Extrusion ◽  
Forming Methods

Severe plastic deformation is defined as metal forming methods in which a very large strain is imposed to a bulk in order to make an ultra-fine grained metal. ECAP is one of the most effective methods in SPD. The influences of main parameters on deformation include extrusion route, extrusion pass, die corner, friction, extrusion speed and so on. In this investigation, a model of ECAP process has been developed based on FEM and effects of extrusion speed on effective strain, load and effective stress imposed in the copper road are researched. The results of simulation have shown that lower extrusion speed can lead to higher load of top die and effective stress while the effect of extrusion speed on effective strain of copper road is slight.

Unique Mechanical Properties of Nanostructured Metals

2007 ◽  
Vol 7 (11) ◽  
pp. 3765-3770 ◽  
Author(s):  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Equivalent Strain ◽  
Coarse Grained ◽  
Roll Bonding ◽  
Nanostructured Metals ◽  
Ultrafine Grained ◽  
Nanocrystalline Structures ◽  
Rolling Deformation

Recently, it becomes possible to fabricate bulk metals having ultrafine grained or nanocrystalline structures of which grain size is in nano-meter dimensions. One of the promising ways to realize bulk nanostructured metals is severe plastic deformation (SPD) above logarithmic equivalent strain of 4. We have developed an original SPD process, named Accumulative Roll Bonding (ARB) using rolling deformation in principle, and have succeeded in fabricating bulk nanostructured sheets of various kinds of metals and alloys. The ARB process and the nanostructured metals fabricated by the ARB are introduced in this paper. The nanostructured metals sometimes perform quite unique mechanical properties, that is rather surprising compared with conventionally coarse grained materials. The unique properties seem to be attributed to the characteristic structures of the nano-metals full of grain boundaries.

REGULARITIES OF FORMATION AND DEGRADATION OF THE MICROSTRUCTURE AND PROPERTIES OF NEW ULTRAFINE-GRAINED LOW-MODULUS Ti–Nb–Mo–Zr ALLOYS

2018 ◽  
pp. 36-48
Author(s):  
Yu. R. Kolobov ◽  
O. A. Golosova ◽  
S. S. Manokhin
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure Torsion ◽  
Diffraction Method ◽  
Simultaneous Action ◽  
Helical Rolling ◽  
Longitudinal Rolling ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Low Modulus

Regularities of the formation of ultrafine-grained (UFG) and submicrocrystalline (SMC) structures in new nickel-free low-modulus Ti–Nb–Mo–Zr titanium β alloys under the action of plastic deformation were studied. Temperature-time ranges of the development of dynamic recrystallization processes under the simultaneous action of temperature and plastic deformation were determined. The recrystallization diagram of II type of the Ti–28Nb–8Mo–12Zr alloy was constructed and analyzed. It was shown using scanning electron microscopy and electron backscatter diffraction method that the UFG structure with an average grain size of no more than 7 μm and high fraction of high-angle grain boundaries is formed in the investigated alloys as a result of longitudinal rolling followed by annealing for quenching. It was found that the formation of the UFG structure leads to a significant increase in the strength and plastic characteristics of these alloys. The regularities of the formation of UFG and SMC structures in the titanium β alloys Ti–28Nb–8Mo–12Zr and VT30 widely used in industry under the action of plastic deformation by the helical rolling method were studied. It was shown that the helical rolling of the VT30 alloy leads to the formation of the homogeneous UFG state as opposite to the developed Ti–28Nb–8Mo–12Zr β alloy where this method causes structure softening with micropores and microcracks formed in the central region. It is possible to form a nanostructured state with an average grain size of about 100 nm in Ti–Nb–Mo–Zr titanium β alloys using high-pressure torsion method.

Production of Nanostructure in Titanium by Cold Rolling

2008 ◽  
Vol 584-586 ◽  
pp. 759-764 ◽  
Author(s):  
Svetlana Malysheva ◽  
G.A. Salishchev ◽  
Sergey Mironov ◽  
Sergey V. Zherebtsov
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Cold Rolling ◽  
Sheet Material ◽  
Coarse Grained ◽  
Sheet Rolling ◽  
Commercial Titanium ◽  
High Level

The paper considers changes in microstructure, texture and mechanical properties of commercial titanium with initial coarse-grained structure during cold sheet rolling. It has been shown that rolling above 75% leads to formation of a uniform nanocrystalline (NC) structure with a grain size of approximately 0.2 'm in the sheet material. The sheets have a high level of mechanical properties which is comparable with the properties of bulk specimens of titanium with NC structure produced by some other method of severe plastic deformation.

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