Effect of the tool geometry on the force mode of the combined radial-direct extrusion with compression

Self Cite

The simulation of the process of combined radial reverse extrusion of hollow parts with a flange has established two fundamentally different, in terms of the components of the kinematic modules, calculation schemes CDZ-1.i and CDZ-2.j, taking into conside ration the possible shape of the boundary of the section of a metal flow inside a workpiece. The comparison of the dependences of the optimal relative rate of metal outflow in the opposite direction for different schemes indicates significant differences in the resulting values in the course of the deformation process. The relevance of this study is due to making it easier to evaluate the use of the combined extrusion process to produce hollow parts with a flange while maintaining the required dimensions compared to simple deformation schemes. We have identified the lack of detailed studies into the technologies for the introduction of combined extrusion schemes, as well as the absence of technological recommendations for determining the force regime and the shape formation of a semi-finished article. The process of the combined extrusion of hollow parts with a flange was investiga ted, thereby selecting different types based on the nature of the metal flow depending on the geometric ratios of the deformation process. We have obtained experimental data on the gradual shape formation of a semi-finished product in the process of deformation at different geometric ratios. The limits of using estimation schemes of the process have been defined to obtain data on the increments in a semi-finished product, including in terms of predicting the formation of a shrinkage cavity in the bottom part. It is recommended that a condition of selecting the appropriate scheme should be the condition for a minimum value of the reduced pressure of deformation i < j. The resulting recommendations make it easier to predict the shape formation and the force mode of extrusion (a deviation from experimentally obtained data can be reduced to 10 %), which would contribute to evaluating the rationality of the combined extrusion processes while ensuring the required dimensions of a part

Section: Energy Methods For Calculating the Force Regime And Incremmentioning

confidence: 99%

Predicting the shape formation of hollow parts with a flange in the process of combined radial-reverse extrusion

Hrudkina¹,

Aliievа²,

Марков³

et al. 2020

Self Cite

“…Calculating the power of plastic deformation forces inside the kinematic module, the forces of cutting with the adjacent modules and friction forces on the surface of the tool make it possible to obtain the reduced pressure in an analytical form [20,21]. Such calculations are required by the triangular modules with a sloping boundary of a curvilinear or straight shape [23,24] or curvilinear modules of different configurations as components of schemes of combined sequential longitudinal-radial extrusion with expansion. At the same time, when selecting the shape and building the kinematic module KPVF, it is necessary to ensure not only the correspondence of its boundaries to experimental data but also the possibility of obtaining analytical expressions of the reduced pressure [17,18,23,24].…”

Section: Development Of An Axial Triangular Kinematic Module With mentioning

confidence: 99%

“…Such calculations are required by the triangular modules with a sloping boundary of a curvilinear or straight shape [23,24] or curvilinear modules of different configurations as components of schemes of combined sequential longitudinal-radial extrusion with expansion. At the same time, when selecting the shape and building the kinematic module KPVF, it is necessary to ensure not only the correspondence of its boundaries to experimental data but also the possibility of obtaining analytical expressions of the reduced pressure [17,18,23,24]. That would make it possible to take full advantage of the energy method and optimize the force mode of the deformation process for the selected variable parameters.…”

Section: Development Of An Axial Triangular Kinematic Module With mentioning

confidence: 99%

Modeling the process of radial-direct extrusion with expansion using a triangular kinematic module

Hrudkina

Aliievа

Марков

et al. 2020

Self Cite

Запропоновано у якості осьового використовувати розроблений трикутний кінематичний модуль 2а з криволінійною похилою межею, що дозволяє описувати характер течії металу в зоні розвороту до радіального видавлювання. На основі енергетичного методу отримано величини потужності сил деформування всередині побудованого кінематичного модуля 2а, потужності сил тертя на межі контакту заготовки з інструментом та потужності сил зрізу із суміжними кінематичними модулями. В результаті отримано аналітичний вираз приведеного тиску деформування осьового трикутного кінематичного модуля 2а з похилою межею, форма якої залежить від параметра α. Проаналізовано можливості оптимізації приведеного тиску деформування за параметром α за різних співвідношень геометричних параметрів модуля та умов тертя. З урахуванням форми суміжного кінематичного модуля 3а запропоновано використання отриманих залежностей приведеного тиску для розрахунків силових режимів процесів комбінованого послідовного радіально-поздовжнього видавлювання з розвиненою радіальною складовою течії металу. Здійснено порівняльний аналіз розрахункових схем ЕМ-2а з розробленим осьовим трикутним кінематичним модулем 2а та ЕМ-2 із використанням осьового прямокутного кінематичного модуля 2 та експериментальними даними моделювання процесу комбінованого радіально-прямого видавлювання з роздачею. Перевищення даних за зусиллям деформування, отриманих на основі схеми ЕМ-2а (із розробленим трикутним модулем з криволінійною межею 2а) та ЕМ-2, від експериментально отриманих складає 12-15 % та 15-20 % відповідно. Це підтверджує раціональність використання розробленого осьового кінематичного модуля 2а з криволінійною межею замість осьового прямокутного кінематичного модуля при моделюванні процесів послідовного радіально-прямого видавлювання з розвиненою радіальною складовою течії металу. Отримані залежності приведеного тиску деформування модуля 2а можуть бути вбудовані у інші розрахункові схеми процесів послідовного радіально-поздовжнього видавлювання. Завдяки цьому зниження отриманих силових параметрів процесу може становити 7-10 % по відношенню до схем, що містять осьовий прямокутний кінематичний модуль 2 Ключові слова: моделювання процесів комбінованого видавлювання, кінематичний модуль, енергетичний метод, процес деформування UDC 621.777.

“…Thus, the shape formation of parts was investigated from the position of possible defect formation in the form of a shrinkage cavity. The possibilities of obtaining data on the increments in a semi-finished product in an analytical form were demonstrated in studies [20,21]. They report the results of modeling the force regime and the shape formation of a semi-finished product by the energy method.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…In this case, dividing each autonomous deformation site into a set of unified kinematic modules has a significant role for subsequent calculations. The base of the developed unified kinematic modules makes it possible to consider various variants of estimation schemes, including the use of kinematic modules with sloping boundaries [4,10,[20][21][22][23]27]. In the case of the combined radial-direct extrusion of parts with an axial protrusion, the CS-1 calculation scheme containing trapezoidal module 4 ( Fig.…”

Section: Development Of An Estimation Scheme Of the Process Of Thementioning

confidence: 99%

Predicting the shape formation of parts with a flange and an axial protrusion in the process of combined aligned radial-direct extrusion

Hrudkina

Aliievа

Марков

et al. 2020

Self Cite

Using the calculation schemes CS-1 (with the presence of a trapezoid module) and CS-1a (with rectangular kinematic modules) has been proposed for the process of the combined radial-direct extrusion of parts with a flange and an axial protrusion. The application of a trapezoidal kinematic module allows the description of the characteristic regions of metal flow, close to the actual course of the process based on the distorted coordinate grids. On the basis of the energy method, the values of the reduced deformation pressure have been obtained using the upper estimate of the power of deformation forces inside the trapezoidal kinematic module. The optimization involved the parameter Rk that determines the position of the surface of the interface of metal flow into an axial protrusion and a flange zone. We have performed a comparative analysis of the theoretical calculations of the magnitude of the reduced deformation pressure and the influence of geometric ratios and friction conditions on the qualitative and quantitative differences in the character of the change in the resulting curves. The overestimation of data on assessing the force mode based on the CS-1a scheme relative to the calculations based on the CS-1 scheme can be as high as 50 % and indicates the rationality of using the latter. This is due to the limitation in the use of the optimization (the absence of the optimization of the height of the deformation site) for the scheme containing elementary rectangular kinematic modules. The deviation from the experimentally obtained increments in an axial protrusion does not exceed 7-10 %, which indicates the validity of the use of the CS-1 estimation scheme with a trape zoidal kinematic module. Thus, it can be argued that it is correct to determine the position of the boundary of the surface of the interface of metal flow into an axial protrusion and a flange zone and the resulting assessment of the formation of a semi-finished product