Article

# Analysis of splitting spinning force by the principal stress method

College of Materials Science and Engineering, Northwestern Polytechnical University, P.O. Box 542, Xi’an 710072, PR China

Journal of Materials Processing Technology (Impact Factor: 2.04). 05/2008; 201(1):267-272. DOI: 10.1016/j.jmatprotec.2007.11.181 - [Show abstract] [Hide abstract]

**ABSTRACT:**The deformation force of a forging is crucial for making high-quality products and for managing the machine’s physical condition. Estimating this deformation force is not easy due to the complex forging process and the complex geometric shape of a forging. In this paper, a process/shape-decomposition modeling method is proposed to estimate this deformation force in the complex forging process. The complex forging process is first decomposed into a group of simple sub-processes using system knowledge. Each sub-process represents one kind of system feature, such as the free unsetting stage, the filling cavity stage or the die kissing stage. In each sub-process, the complex geometric shape is then decomposed into many easily modeled sub-units, upon which the deformation force model of each sub-unit is built as the sub-model. All sub-models are further integrated to form a global deformation force model for the whole forging process. The continuities of this global model, between two adjacent sub-units and between two adjacent sub-processes, are also considered and guaranteed. Its unknown parameters are identified using deformation force data, which can be indirectly obtained via the motion model of the hydraulic press machine (HPM). Experiments and simulations finally demonstrate and test the effectiveness of the proposed modeling method.International Journal of Mechanical Sciences 11/2014; 90. · 2.06 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**Magnesium alloy AZ31 shows excellent ductility and formability at elevated temperatures, and using hot splitting spinning it can be formed into a structural component subjected to impact loadings, such as, a wheel hub of aero undercarriage or kinds of light whole wheels. In this paper, based on the analysis of microstructures and deformation characteristics of magnesium alloy AZ31, a reasonable deformation temperature range is obtained during the thermoplastic forming process. Adopting a flow stress model of magnesium alloy AZ31 considering the dynamic recrystallization (DRX), a 3D elastic–plastic FE model of hot splitting spinning of magnesium alloy AZ31 is established based on the FEM software platform of ABAQUS/Explicit and a developed 3D-FE model of cold splitting spinning, and its reliability is validated. Furthermore, field distributions of deformed component, including temperature fields, stress fields and strain fields, and variations of different nodal temperatures are obtained. And the influencing laws of different initial temperatures of disk blank and different feed rates of splitting roller on forming quality of deformed flanges are investigated, consequently the optimal forming temperature is approximate 300°C and the optimal feed rate of splitting roller ranges from 1 to 3mm/s during the hot splitting spinning process of magnesium alloy AZ31. The results may help to understand the forming characteristics and optimum design of the hot splitting spinning process.Computational Materials Science 01/2010; 47(3):857-866. · 1.88 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**High pressure torsion (HPT) is useful for achieving substantial grain refinement to ultrafine grained/nanocrystalline states in bulk metallic solids. Most publications that analyzed the HPT process used experimental and numerical simulation approaches, whereas theoretical stress analyses for the HPT process are rare. Because of the key role of compression stage for the deformation of HPT, this paper aims to conduct a theoretical analysis and to establish a practical formula for stress and forming parameters of HPT process using the slab analysis method. Three equations were obtained via equations derivation to describe the normal stress states corresponding to the three zones of plastic deformation for HPT process as stick zone, drag zone and slip zone. As to the compression stage of HPT, the stress distribution results using the finite element method agree well with those using the slab analysis method. There are drag and stick zones on the contact surface of the HPT sample, as verified by the finite element method (FEM) and slab analysis method.Metals and Materials International 09/2013; 19(5):1021-1027. · 1.22 Impact Factor

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