Papers by Keyword: Asymmetric Rolling

Abstract: This study investigates the influence of symmetric and asymmetric hot rolling on the microstructural evolution and mechanical performance of a homogenized Mg–1.5Zn–0.5Ca (ZC1) alloy. X-ray diffraction confirmed phase stability across all processing conditions, with α-Mg as the primary matrix and Mg₆Zn₃Ca₂ as the secondary phase. Scanning electron microscopy revealed progressive fragmentation and redistribution of intermetallic particles upon rolling, with asymmetric rolling introducing higher shear strain and promoting dynamic recrystallization. Mechanical testing showed that symmetric rolling delivered the most favorable strength–ductility combination (UTS: 230 MPa, Elongation: 37%), while asymmetric rolling exhibited the highest yield strength (121 MPa) and microhardness (59 HV). Despite the intensified strain effects in asymmetric rolling, symmetric rolling provided superior mechanical synergy due to more uniform grain refinement and stable phase distribution. The findings highlight symmetric rolling as a robust and scalable deformation route for enhancing mechanical performance in Mg-Zn-Ca alloy systems.

Abstract: Severe plastic deformation (SPD) with strong shear component is required to promote both grain refinement and texture randomization. When Asymmetric rolling (AR) is applied as asymmetric accumulative roll bonding (AARB), it enables the production of architectured microstructures and metallic composites. Finite element (FE) simulations of AR and AARB were employed to understand the influence of pass thickness reduction (PTR) on the through thickness variation of the velocity gradient. The influence of the PTR up to a total thickness reduction of 50% and the effect of a single 50% reduction step in a bi-layer bonding condition was analyzed. The influence of these process parameters on the strain and rigid body rotation components was compared with the experimental data obtained on an AA1050 aluminum. A better shear to compression ratio across the sheet thickness is achieved by PTRs lower than 30%; at a PTR of 50% the texture is dominated by the frictional shear generated at the roll-sheet interface and the process has a stronger compressive character. This indicates that simple ARB followed by AR with smaller PTRs should generate a better shear distribution than AARB alone.

Abstract: Asymmetric rolling with different work roll circumferential speeds is a process that can be used for improvement of mechanical properties of the processed metals and alloys. Development of the model, which allow to calculate the stress-strain state occurring in the microstructure of the ferritic-pearlitic steels during asymmetric rolling, was the main objective of this paper. Macro level models do not take into account the complicated behavior of the ferritic-pearlitic microstructure in the micro scale. Therefore, development of modelling methods, which allow predicting the properties distribution in the metal volume with the behavioral features of the microstructure under the influence of the deformation, was needed. Representative Volume Element (RVE), representing ferritic-pearlitic steel microstructure, was developed. Simulations of the asymmetric rolling process were performed and local deformation of each structural component was predicted. Selected results, as well as discussion of the effect of microstructure on obtained stress and strain distributions, are presented in the paper. Results of multiscale simulation analysis of the deformation characteristics, presented in this study, can be used for optimization of the asymmetric rolling process.

Abstract: Physical simulation of the stress-strain state and microstructure evolution, which are similar to that occurring during asymmetric rolling with a large strain, is very important for design of technologies of producing ultra fine grained metallic materials. This paper presents the results of optimization of specimen geometry and a special multi-cycle shear-compression technique for the physical simulation of asymmetric rolling with a large strain up to e ~ 4. The specimen consisted of a parallelepiped having an inclined gauge section created by two diametrically opposed semi-circular slots which were machined at 45°. The specimen was compressed between two flat dies during shear-compression testing in accordance to the special multi-cycle scheme. Each cycle of the shear-compression testing consisted of two steps. The first step included height reduction of specimen, after that specimen was rotated by 90º. The second step included length reduction of the specimen for getting the quasi original shape of a parallelepiped. The specimen provided simultaneous pure and simple shear in an inclined gauge-section. The level of effective strain was controlled through adjustment of the specimen geometry, height reduction, load application direction and number of cycles of shear-compression. Gauge thickness, width and radius of the specimen were optimized by FEM with using of software DEFORM 3D. Numerical simulation and comparison of the stress-strain state during shear-compression testing and asymmetric rolling of low-carbon steel AISI 1010 were performed. Results of FEM analysis of the applicability of the multi-cycle shear-compression testing to the modeling of asymmetric rolling were discussed.

Abstract: The Goss texture, or {110}<001>, shows soft magnetic property due to the <100>. Therefore, it is one of the most important texture in Si steels. The Goss texture is one of the shear deformation texture in steel which has bcc structure. During the asymmetric rolling, shear deformation is imposed on steel sheets. To obtain the Goss texture, the carbon and Si steel sheets were asymmetrically rolled by 50-85% reduction in thickness at room temperature and at 770 °C. The asymmetric rolling of steel sheets gave rise to the well-developed Goss texture to them.

Abstract: Magnesium alloy is honored as green engineering material for its low density, high specific strength, high specific rigidity, well cutting processing property, well electromagnetic shielding property, heat conduction and easy to recycle. In this paper, AZ31 Magnesium alloy sheet at difference thickness were prepared by symmetric and asymmetric rolling employed with six-roller mill. Microstructure of the two kinds of rolling magnesium alloy thin sheets at 0.5mm thickness were investigated. The grain distribution of AZ31magnesium alloy sheets made by asymmetry rolling at room temperature are more uniform than those made by symmetry process. The grains made by asymmetry are more tiny and the tensile strength and elongation increased obviously and the mechanical properties got better. At room temperature, value of n increased. Large value of n benefit to stamping forming. At room temperature, the value of LDR of asymmetry rolling sheets is 1.26, which was higher than symmetry rolling. So asymmetry rolling benefits to stamping forming.

Abstract: For the manufacture of good quality strips by rolling processes, the bending residual stress of the strip is one of the most important qualities to be controlled. Most reports on strip bending behavior have focused on thick plates produced under batch rolling conditions [1, 2], and few reports have examined continuous rolling of thin plates. In this report, we conducted a single-drive rolling test with a strip having the thickness of 0.23mm and a 2Hi test mill with work rolls 410mm in diameter. We also calculated the pressure distribution and warping curvature. The model used here was based on the Orowan model constructed by Morimoto and Yanagimoto [3]. In this calculation, the roll bite was separated into 3 sections, i.e., forward slip region, backward slip region and cross shear region. In the calculation results, the pressure distribution showed the existence of a pressure well in the cross shear region, as also reported by Zorowski et al. [4] The curvature in the calculation result increased as the reduction ratio increased up to 10%, but decreased with increasing reduction ratios larger than 10%. This tendency was the same as the measured curvature in the experiment, and was considered to be caused by the moment by friction force at the cross shear region and also the aspect ratio of the cross shear region.

Abstract: The mechanism of a severe plastic deformation during asymmetric rolling comes from its large equivalent strain, which is composed of a compressive strain and additional shear strain. Physical simulation of shear strain, which is similar to that occurring in asymmetric rolling processes, is very important for design of technology of ultrafine grain material production. Shear testing is complicated because a state of large shear is not easily achievable in most specimen geometries. Application of the shear-compression testing and specimen geometry to physical simulation of asymmetric rolling is discussed in the paper. The results of the numerical simulation and comparison of the stress-strain state during shear-compression testing and asymmetric sheet rolling are presented. The results of the investigation can be used to optimize the physical simulation of asymmetric rolling processes and for the design of the technology for ultrafine grain material production by means of a severe plastic deformation.

Abstract: B₄C/Al composite was a promising neutron absorb material. In this work, B₄C/Al composite sheets were asymmetrically rolled and annealed. The asymmetric (ASR) condition was introduced by applying mismatched roll diameters with diameter ratios of 1.1, 1.2 and 1.3, respectively., while the symmetric rolling (SR) was used as the control experiment. Mechanical properties and microstructures of the composite were tested after cold rolling and annealing. Results showed that: ASR with small diameter ratio decreased the texture volume fraction in the B₄C/Al composite, but when diameter ratio of ASR reached 1.3 new slip systems were actuated and the texture volume fraction started to increase. The average grain size of the aluminium matrix was smaller after ASR, and it decreased with the increasing diameter ratio. The hardness of B₄C/Al composite after ASR was about 40% higher than the one rolled by symmetric rolling, proved that ASR is a promising way to enhance the properties of B₄C/Al composite.

Abstract: The average plastic strain ratio (the R-value) and the anisotropy parameter |ΔR| calculated from the measured texture of AA1050 Al alloy sheet treated by the heavy asymmetric rolling by 84% reduction in thickness and subsequent annealing for 1 h at 500 °C, followed by light rolling by 10% or 20% reduction in thickness and the subsequent annealing for 1 h at 500 °C increased by 1.52 times that of the non-processed specimen and reduced to 1/12 times that of the non-processed specimen, respectively.