Calculation of the size of a hollow workpiece with a thin wall with interchangeabe thickness and determination of the parameters of its crimping in a matrix with a cone-cylindrical deforming surface

Mathematical models were created using the finite element method and research was carried out on options for hot, semi-hot and cold crimping in a container and matrix of a special profile of axisymmetric hollow blanks made of high-carbon steel with variable wall thickness along the height. A plastic model of metal is used. Before hot and semi-hot crimping, the part of the workpiece was heated at the height to be deformed. The shape and dimensions of the initial blank for crimping were determined by calculation, which ensured the required dimensions of the product. The use of a container and a matrix of a special profile with a deforming surface made with ring protrusions made it possible to obtain a product in one pass for the considered options for crimping due to the reduction of the influence of frictional forces during molding. The rate of deformation was determined to maintain the mode of hot and semi-hot deformation during crimping. The dependence of the axial force on the deforming tool on the movement of the punch and the distribution of specific forces on the contacting surfaces was established. The use of cold pressing leads to an increase in the accuracy of the shape and dimensions of the product, a decrease in energy consumption and metal consumption. The final stress-strained state of the metal, the shape and dimensions of the product are determined. Based on the distribution of deformation intensity, an evaluation of the working of the metal structure by semi-hot and cold plastic deformation was carried out, and the yield point of the metal after crimping was predicted. On the basis of the simulation data, a design of the general appearance of the die equipment for cold crimping was developed.

Section: аналіз літературних даних та постановка проблемиunclassified

Options of crimping in a container and matrices of a special profile of axysymmetric hollow billets made of C60 steel

Kaliuzhnyi,

Levchenko,

Kaliuzhnyi

et al. 2023

“…По причині потовщення обтиснутої частини стінки в процесі формоутворення обтиском виникають суттєві складнощі при визначенні форми і розмірів вихідної заготовки для обтиску, щоб отримати необхідні кінцеві розміри внутрішньої поверхні порожнини виробу, яка в подальшому не підлягає обробленню. Моделювання з використанням МСЕ дозволяє також вирішити і цю проблему [11], а встановлену форму і розміри заготовки можна отримати на попередньому переході перед обтиском витягуванням з потоншенням.…”

Section: вступunclassified

“…Схеми двох варіантів закритого обтиску порожнистої заготовки в матрицях спеціального профілю зображені на рис. Спочатку моделюванням МСЕ були визначені форма і розміри заготовки для обтиску по методиці джерела [11], яка полягає в вирівнюванні роздачою стінки обтиснутої частини виробу. Процес моделювання розділений на 2 стадії -початкову і заключну, які показані на рис.…”

Section: вступunclassified

Hot crimping in a special profile matrix of axisymmetric hollow workpieces from high carbon steel

Kaliuzhnyi¹,

Sytnyk²,

Titarenko³

2022

Using the finite element method, mathematical models were created and studies were carried out of direct and reverse methods of hot crimping in a matrix of a special profile of hollow workpieces made of high-carbon steel with a variable wall thickness along the height. A plastic model of metal and cylindrical coordinates are used. By calculation, the shape and dimensions of the initial workpiece for crimping were established, which provided the required dimensions of the product. Before crimping, a part of the billet was heated along the height, which was subject to deformation in the matrix. The use of a matrix of a special profile with a deforming surface made with annular protrusions made it possible to obtain a product in one step due to a decrease in the influence of friction forces during shaping. The deformation rate is determined to comply with the hot deformation mode during the crimping. The dependences of the axial force on the deforming tool on the movement of punches and the distribution of specific forces on the contact surfaces are established. The use of direct crimping leads to a decrease in forces modes and specific forces on the tool. The final stress-strain state of the metal, the shape and dimensions of the product are determined. According to the distribution of strain intensity, an assessment was made of the elaboration of the metal structure by plastic deformation. Based on the simulation data, a design of the general view of the die tooling for direct crimping has been developed.

“…Тому виникають значні складнощі по встановленню величини потовщення при обтиску напівфабрикатів, які мають стінку змінної товщини по висоті, що потребує призначення напусків і проведення токарної обробки, або виконання додаткових експериментальних робіт для виявлення форми і розмірів стінки по висоті напівфабрикату перед обтиском. Авторами [4,11] В вихідному стані штампу відстань між торцем пуансона 13 і матрицею 1 ненабагато більша за висоту напівфабрикату, який отримується видавлюванням. При цьому пружини 27 розтиснуті і кільце знімач 9 опущений.…”

Section: вступunclassified

Innovative Technology for Stamping a Small-Sized Sleeve Blank

Калюжный¹,

Yarmolenko²,

Marchuk³

2021

The work is devoted to the development of an innovative technology of stamping from low-carbon steel for small-size liner blanks. The sequence of punching transitions includes a cold back extrusion operation, two cold drawing operations with thinning, and a cold crimping operation. Simulation with the use of the finite element method established the forces and specific forces during operations, the thermal effect during shaping, the shape and size of semi-finished products with distributions of the intensity of deformations. An elastoplastic metal model was used, which made it possible to reveal the deformation forces, tool extraction from deformed semifinished products and the effort to remove semifinished products from the dies. A hollow semi-finished product is obtained by reverse extrusion. The possibility of carrying out the first drawing operation with thinning through two sequentially located dies with the formation of a hole in the bottom part is shown. After this operation, annealing of the semi-finished product is required to restore plasticity. In the second operation, thinning stretching. The shape and dimensions of the wall of the semi-finished product after the second drawing, the distribution of the intensity of deformations in it are determined from the condition of reaching the final dimensions and mechanical properties of the sleeve blank at the last crimping operation. For this, the deformations obtained as a result of the second drawing are taken into account when modeling the crimp. For each transition of stamping, a construction of stamping equipment has been developed. The proposed technology for stamping a sleeve blank can be implemented on a universal pressing equipment, has a high productivity due to a reduction in the number of transitions and minimizes mechanical processing.