The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform
Zhengyi Jiang - One of the best experts on this subject based on the ideXlab platform.
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understanding the role of water based nanolubricants in micro Flexible Rolling of aluminium
Tribology International, 2020Co-Authors: Haibo Xie, Mingshuai Huo, Jingwei Zhao, Fanghui Jia, Fei Lin, Hongmei Zhang, Zhengyi JiangAbstract:Abstract To comprehend the role of water-based nanolubricant in micro Flexible Rolling, corresponding characterisation with respect to different concentrations of nanolubricants, surface roughness variation subjected to each micro Flexible Rolling phase and dispersion of nanoparticles (NPs) were studied systematically. The results reveal that increasing NPs get trapped into the surfaces from the thicker zone to the thinner zone. Downward transition zone with favourable deformation features leads to the smoother surface roughness. Nanolubricants can effectively decrease Rolling traces due to the beneficial nanolubrication mechanisms. Notably, the maximum reduction for Rolling force is around 18% for the case under 2.0 wt% nanolubricant Rolling condition. The current study provides great potential insights in how nanolubrication takes effect in microforming areas.
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effects of micro Flexible Rolling and annealing on microstructure microhardness and texture of aluminium alloy
Materials Characterization, 2019Co-Authors: Zhengyi Jiang, Haibo Xie, Mingshuai Huo, Jingwei Zhao, Fanghui Jia, Hongmei ZhangAbstract:Abstract The microstructure and texture after plastic deformation are strongly dependent on the corresponding manufacturing process and subsequent annealing which significantly affect the properties of the final products. In this study, 1060 aluminium alloy with a thickness of 464 μm was micro flexibly rolled to a constant thickness ratio of 3.6 by a combined control of the roll gap, the Rolling speed and the roll lifting speed. Afterwards, the rolled specimens were subjected to isochronal annealing at a temperature range of 200 to 400 °C for 30 min and isothermal annealing at 400 °C for 10–60 min. Results indicate that the microstructure, microhardness and texture of each thickness zone are distinctly influenced by the Rolling parameters and annealing conditions. Specimens annealed at 400 °C for 30 min result in a relatively steady hardness distribution along the transition zones. Typical β fibre texture is observed in the specimens suffered from annealing while S is predominant in both micro flexibly rolled and annealed specimens.
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evaluation and optimisation of micro Flexible Rolling process parameters by orthogonal trial design
The International Journal of Advanced Manufacturing Technology, 2018Co-Authors: Zhengyi Jiang, Wenzhen XiaAbstract:As the strip thickness is in the range of sub-millimetre in micro Flexible Rolling, springback ratio in thickness direction has a significant impact on product quality, which is influenced by various process parameters during forming process. This paper focuses on performing a numerical and experimental investigation to evaluate the effects of initial strip thickness, friction coefficient and Rolling speed on the springback ratio in thickness direction during the micro Flexible Rolling process with reductions of 20 to 50% using orthogonal trial design, and wherein the three-level factors orthogonal array is chosen and nine representative orthogonal trials for each reduction have been implemented. With the significance of each process parameter for each reduction identified by variance analysis, an optimum proposal for each reduction to obtain the minimum springback ratio has been determined numerically, which is afterwards confirmed by experimental data. Moreover, a qualitative estimate of the influences of process parameters on the Rolling force, as well as a quantitative analysis of the relationship between the length of thickness transition zone and the parameter level have also been carried out with reference to the obtained results.
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Analysis of Springback Behaviour in Micro Flexible Rolling of Crystalline Materials
Hindawi Limited, 2018Co-Authors: Zhengyi Jiang, Xiaogang Wang, Cunlong ZhouAbstract:This paper presents a constitutive modelling of the polycrystalline thin metal strip under a state of combined loading in microFlexible Rolling. The concept of grained inhomogeneity is incorporated into the classic Chaboche hardening model that accounts for the Bauschinger effect, in order to provide more precise description and analysis of the springback mechanism in the particular forming operation. The model is first implemented in the finite element program ABAQUS to numerically predict the stress-strain relationship of 304 stainless steel specimens over a range of average grain sizes. After validation of the developed model by comparison of predicted curves and actual stress-strain data points, it is further applied to predict the thickness directional springback in microFlexible Rolling of 304 stainless steel strips with initial thickness of 250 µm and reduction changing from 5 to 10%. The model predictions show a reasonable agreement with the experimental measurements and have proven to be more accurate than those obtained from the conventional multilinear isotropic hardening model in combination with the Voronoi tessellation technique. In addition, the variation of thickness directional springback along with the scatter effect is compared and analysed in regard to the average grain size utilising both qualitative and quantitative approaches in respect of distinct types of data at different reductions
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study of micro Flexible Rolling based on grained inhomogeneity
International Journal of Mechanical Sciences, 2017Co-Authors: Zhengyi Jiang, Dongbin Wei, Qingqiang ChenAbstract:Abstract This paper shows an analytical, numerical and experimental investigation to comprehend the role of grained inhomogeneity which plays in micro Flexible Rolling in terms of the average Rolling force and the thickness directional springback of the workpiece after it exits the roll bite zone. Miniature tensile tests and micro hardness tests are accomplished to identify the scattered stress-strain curves for 500 μm thick aluminium alloy 1060 samples with grain size of approximately 23-71 µm and to determine the weighted heterogeneity coefficient for each sample separately, according to which the theoretical calculations and numerical simulations based upon 3D Voronoi tessellation technique have been performed under actual experimental conditions where reductions of 25 to 50 % are selected. The scattering effect associated with the anisotropic nature of single grains has been perceived in the micro Flexible Rolling process and both the analytical and finite element models developed have been validated via experimental data to hold promise for predicting the Rolling force and the thickness directional springback of the workpiece, as well as boosting the thickness profile control performance of the micro Flexible Rolling mill.
Mingshuai Huo - One of the best experts on this subject based on the ideXlab platform.
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understanding the role of water based nanolubricants in micro Flexible Rolling of aluminium
Tribology International, 2020Co-Authors: Haibo Xie, Mingshuai Huo, Jingwei Zhao, Fanghui Jia, Fei Lin, Hongmei Zhang, Zhengyi JiangAbstract:Abstract To comprehend the role of water-based nanolubricant in micro Flexible Rolling, corresponding characterisation with respect to different concentrations of nanolubricants, surface roughness variation subjected to each micro Flexible Rolling phase and dispersion of nanoparticles (NPs) were studied systematically. The results reveal that increasing NPs get trapped into the surfaces from the thicker zone to the thinner zone. Downward transition zone with favourable deformation features leads to the smoother surface roughness. Nanolubricants can effectively decrease Rolling traces due to the beneficial nanolubrication mechanisms. Notably, the maximum reduction for Rolling force is around 18% for the case under 2.0 wt% nanolubricant Rolling condition. The current study provides great potential insights in how nanolubrication takes effect in microforming areas.
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effects of micro Flexible Rolling and annealing on microstructure microhardness and texture of aluminium alloy
Materials Characterization, 2019Co-Authors: Zhengyi Jiang, Haibo Xie, Mingshuai Huo, Jingwei Zhao, Fanghui Jia, Hongmei ZhangAbstract:Abstract The microstructure and texture after plastic deformation are strongly dependent on the corresponding manufacturing process and subsequent annealing which significantly affect the properties of the final products. In this study, 1060 aluminium alloy with a thickness of 464 μm was micro flexibly rolled to a constant thickness ratio of 3.6 by a combined control of the roll gap, the Rolling speed and the roll lifting speed. Afterwards, the rolled specimens were subjected to isochronal annealing at a temperature range of 200 to 400 °C for 30 min and isothermal annealing at 400 °C for 10–60 min. Results indicate that the microstructure, microhardness and texture of each thickness zone are distinctly influenced by the Rolling parameters and annealing conditions. Specimens annealed at 400 °C for 30 min result in a relatively steady hardness distribution along the transition zones. Typical β fibre texture is observed in the specimens suffered from annealing while S is predominant in both micro flexibly rolled and annealed specimens.
Mingzhe Li - One of the best experts on this subject based on the ideXlab platform.
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Study on the utilization rate of processed spherical surface part in Flexible Rolling
The International Journal of Advanced Manufacturing Technology, 2019Co-Authors: Yi Li, Mingzhe LiAbstract:Flexible Rolling is a novel and effective process for double curvature parts and it is suitable for various shapes and small batch production. Taking spherical surface parts as an example, the utilization rate of the processed curvature part in Flexible Rolling was studied for the first time. In the finite element model, the processed surface part is divided into three areas by forming characteristics. The formation mechanisms of forming areas are discussed. Meanwhile, the effect of the ratio among length, width, and thickness on the utilization rate of processed surface part is studied deeply. The results show that the processed surface part is divided into three areas by plastic deformation in the longitude direction. The bending deformation distribution is continuously changing in the transition-forming areas and stable in the stable-forming area. The ratio among the length, width, and thickness has a great effect on the utilization rate of processed surface part. When the width and thickness remain constant, the utilization rate is increasing with increasing length ratio. When the length and thickness remain constant, the utilization rate is increasing with decreasing width ratio. When the length and width remain constant, the utilization rate is increasing with decreasing thickness ratio. The numerical simulation results are in accord with experiment results.
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surface Flexible Rolling for three dimensional sheet metal parts
Journal of Materials Processing Technology, 2014Co-Authors: Renjun Li, Mingzhe LiAbstract:Abstract To realize highly effective and continuous fabrication of three-dimensional (3D) sheet metal parts, a new forming method, surface Flexible Rolling forming, has been investigated. This method takes only two integral Flexible rolls as the forming tool. In the forming process, a non-uniform elongation in the Rolling direction and a bending deformation in the thickness direction occur simultaneously, and finally three-dimensional surface parts are formed. In this work, the basic principle and forming mechanism of surface Flexible Rolling are studied. A method to calculate the transversal curvature radius of the arc-shaped roll is brought forward, while the feasibility is verified by the explicit dynamic finite element analysis. An experimental device has been developed and the forming experiments have been performed. Typical 3D surface parts including the convex and saddle surface parts have been obtained. Finite element model of surface Flexible Rolling is established and the effect of forming parameters such as reduction, velocity, bending radius and friction on the surface shape is analyzed. The forming effects including shape errors and thickness changes are studied by the deviation analysis. The results indicate that the formed surface is quite close to the criteria one; the thickness of the parts changes gradually and keeps within a narrow range. The experimental formed parts are measured and the forming accuracy is investigated. The results show that the accuracy is high, and are consistent with the simulation.
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Research on forming precision of Flexible Rolling method for three-dimensional surface parts through simulation
The International Journal of Advanced Manufacturing Technology, 2014Co-Authors: Daming Wang, Mingzhe LiAbstract:Flexible Rolling is a novel forming process for three-dimensional surface parts using a pair of bendable rolls. By contRolling the distribution of the gap between the upper and lower forming rolls in the Rolling process, the sheet metal is nonuniformly thinned in the thickness direction and the longitudinal elongation is different in the width direction of the sheet metal, which makes the sheet metal deform in Rolling direction. With the rotation of the bendable rolls, the sheet metal is deformed consecutively and a three-dimensional surface part could be obtained. A small experimental device has been designed. Finite element analysis (FEA) model is established. Spherical surface and saddle surface are simulated, and their experimental results are presented. The major purpose of the present work is to analyze the forming precision of Flexible Rolling and the reasons for the shape errors through simulated and experimental results. The results demonstrate that the proposed process is a feasible and effective way of forming three-dimensional surface parts.
Gerhard Hirt - One of the best experts on this subject based on the ideXlab platform.
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increasing of the drawing depth using tailor rolled blanks numerical and experimental analysis
International Journal of Machine Tools & Manufacture, 2008Co-Authors: Alexander Meyer, Burkhard Wietbrock, Gerhard HirtAbstract:Abstract Deep drawing is a common sheet metal forming process. In most cases, sheets with constant thicknesses are formed. At the end of the previous century, new innovative blank technologies have been established for weight saving purposes. The development of the Flexible Rolling process is an illustrating example for this progression. By changing the roll gap during Rolling, longitudinal thickness transitions are produced. The innovative semi-finished product, which is produced in this manner, is called tailor rolled blank (TRB). Its behaviour and characteristics during further processing, especially in forming, are topics of present research. The main emphasis of this paper is placed on the idea that TRB can be used to increase the maximum deep drawing depth compared to blanks having a constant thickness. This can be realised by “weakening” certain areas of the blank in a way that the load in failure at critical areas is reduced. To ensure weight saving in addition to increasing the maximum deep drawing depth, the maximum sheet thickness of the TRB is equal to the constant thickness of the other blanks. The concept is first analysed with the help of numerical simulations and then verified by experimental work.
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Production of blanks with thickness transitions in longitudinal and lateral direction through 3D-Strip Profile Rolling
International Journal of Material Forming, 2008Co-Authors: N. Ryabkov, K. Van Putten, Frank Jäckel, Gerhard HirtAbstract:3D-Strip Profile Rolling should enable the production of blanks with a defined thickness profile in latitudinal and longitudinal direction. The production chain of 3D-Strip Profile Rolling will combine Flexible Rolling in a first production step with Strip Profile Rolling in a second step. The control system to adjust the roll gap during 3D-Strip Profile Rolling is currently under development. Nevertheless, some first experiments have shown the general feasibility to produce 3D-profiled blanks. In 3D-Strip Profile Rolling the material will strain harden differently on different locations. This results in a variation of the material properties of the strip. Lateral spread, elastic roll stand deformation and local deformation will be influenced by this variation. To investigate these influences on the complete production process, the complete production chain needs to be modelled in the future with aid of finite element simulations. In this publication a first simulation model is used to study the influence of different grades of strain hardening in a Taylor Rolled Blank on the bulge formation that occurs during the Rolling of a rill in this Tailor Rolled Blank.
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numerical research and optimisation of high pressure sheet metal forming of tailor rolled blanks
Journal of Materials Processing Technology, 2006Co-Authors: Marcus Urban, Martin Krahn, Gerhard Hirt, Reiner KoppAbstract:Abstract The high-pressure sheet metal forming of tailor rolled blanks allows the production of optimised components specially developed for their future function, which cannot be made from conventionally rolled sheet metal. The research aims at showing that the two processes, i.e. Flexible Rolling and high-pressure sheet metal forming, can be well represented in finite element simulations. By linking the finite element models with a combinatory optimisation tool it is possible to simulate and optimise the entire process chain and/or the product itself. Within this paper the forming restrictions of the high pressure sheet metal forming of tailor rolled blanks are presented. Furthermore, two optimisations, considering not only the process chain but also the behaviour under loading conditions, are shown.
Marion Merklein - One of the best experts on this subject based on the ideXlab platform.
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manufacturing of tailored blanks with pre shaped involute gearings by using a Flexible Rolling process and its application in a sheet bulk metal forming process
2021Co-Authors: Manfred Vogel, Robert Schulte, Onur Kaya, Marion MerkleinAbstract:Nowadays, the efficient manufacturing of functional components in short process chains is important due to the goal of a further reduction of greenhouse gases. Additionally, there are also technical demands like functional integration combined with an improvement of the component’s properties. Previous investigations have shown that the application of tailored blanks with a defined thickness profile can lead to an improvement of the geometrical and mechanical properties of functional components. However, common forming processes reach their limits. A promising approach to enlarge these process limits is the application of bulk forming operations to sheet metals, the so-called sheet–bulk metal forming (SBMF). Within this process class, one possibility for manufacturing such blanks is a Flexible Rolling process. As a result of movement of two Rolling tools in combination with a die cavity in the lower tool, a defined geometry can be manufactured perpendicular to the sheet plane. In order to raise the complexity combined with a shorter process chain and thus to fulfil the requirements defined by the subsequent forming operations, a new design that contains a preform of involute gearings is introduced. In order to acquire process knowledge, the mild deep drawing steel DC04 with an initial sheet thickness of t0 = 2.0 mm is used. Furthermore, the subsequent application of the tailored blanks in a combined deep drawing and upsetting process is shown, with a characterization of the geometrical and mechanical properties.
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Flexible Rolling of rotational symmetric tailored blanks with a two sided thickness profile
Procedia Manufacturing, 2019Co-Authors: Manfred Vogel, Marion MerkleinAbstract:Abstract The application of bulk forming operations to sheet metals leads to an increase of the material efficiency due to the enhancement of the process limits compared to conventional forming processes. The main challenges within the process class of sheet-bulk metal forming are high resulting forming forces and a defined control of the material flow. Additionally, the initial blank thickness influences the resulting quality of the geometrical and mechanical properties of functional components, like synchronizer rings. Previous investigations have shown that the application of tailored blanks with a defined one-sided thickness profile can meet these challenges which lead to an increase of the sufficient die filling of functional elements in subsequent forming processes. Due to the further increase of the geometrical complexity with functional elements in- and outside of the frame like carriers or gear teeth, the layout of the tailored blank has to be adapted. Thus, a two-sided thickness profile is necessary, for achieving the sufficient die filling of the functional elements. One possibility for manufacturing these semi-finished parts is a Flexible Rolling process which is used within the presented work. Thereby, it is necessary to develop a new process strategy for achieving a material thickening on both sides, rolled- as well as die-sided. For enabling a homogeneous material flow, the deep drawing mild steel DC04 with an initial sheet thickness of t 0 = 3 mm is used, due to a high formability of this material. The tailored blanks are hereby analyzed regarding the resulting process forces, geometrical dimensions like the sheet thickness, mechanical properties such as the hardness distribution and the resulting surface roughness in important areas.
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a new strategy for manufacturing tailored blanks by a Flexible Rolling process
Materials Science Forum, 2016Co-Authors: Philipp Hildenbrand, Michael Lechner, Marion MerkleinAbstract:Applying bulk forming processes on sheet metals enables the manufacturing of functional components with local wall thickness distributions. Using tailored blanks improves the forming of the functional components and increases the material efficiency. One process for manufacturing tailored blanks with defined sheet thickness distributions is a Flexible Rolling process. However, this process requires a complex process strategy. Additionally, tailored blanks out of high-strength steels from this process have failed in subsequent forming. Thus, a new Rolling concept with a defined shaping of the material into a die cavity has been developed. This new concept requires the development of a new process strategy. In this paper, the general qualification and first results of the new concept are presented.
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Flexible Rolling of process adapted semi finished parts and its application in a sheet bulk metal forming process
Key Engineering Materials, 2015Co-Authors: Philipp Hildenbrand, Thomas Schneider, Marion MerkleinAbstract:By applying bulk forming processes on sheet metals, thin-walled functional components with locally restricted wall thickness variations can be manufactured by forming operations. Using tailored blanks with a modified sheet thickness gradient instead of conventional blanks, an efficient contRolling of the material flow can be achieved. One possible process to manufacture these semi-finished parts is a Flexible Rolling process. Based on an established process strategy new results for steels of differing strength and work-hardening behavior are presented in this paper. The influences of each material on the resulting process forces and blank properties regarding the same target geometry are discussed. The tailored blanks are hereby analyzed by their geometrical dimensions, like sheet thickness, and their mechanical properties, e.g. hardness distribution. Additionally, the possibilities of processing these tailored blanks in a deep-drawing and upsetting process are presented with a hereby focus on the residual formability of the tailored blanks.