Сучасні технології точного об’ємного штампування

Статтю присвячено порівнянню та оцінюванню технологічних процесів точного об’ємного штампування. Показані протиріччя у визначеннях понять «точне об’ємне штампування» (ТОШ). Розглянуті важливі аспекти точності виготовлення деталей гарячим об’ємним штампуванням та холодним видавлюванням. Обговорене питання про класифікацію точних методів об’ємного штампуванняThe paper is devoted to the modern technologies of precision volumetric die forging comparison and estimation. There are shown the contradictions in interpretation of the term “precision volumetric die forging”. The author examined important aspects of precision volumetric hot die forging und cold extrusion and leads to recommendations, witch gives possibility to raise the exactnes

Effect of Relief-hole Diameter on Die Elastic Deformation during Cold Precision Forging of Helical Gears

During cold precision forging of helical gears, the die experiences high forming pressure resulting in elastic deformation of the die, a main factor affecting dimensional accuracy of a formed gear. The divided flow method in material plastic deformation is an effective way to reduce the forming force and the die pressure during cold precision forging of helical gears. In this study, by utilizing the flow-relief-hole method, a billet design with different initial diameters of the relief-hole is developed to improve the dimensional accuracy of cold forging gears. Three-dimensional Finite Element (FE) models are established to simulate the plastic deformation process of billet during cold precision forging of a helical gear and to determine the forming force acting on the die. Further models of die stress analysis are developed to examine the die elastic deformation and distribution of the displacement. Effects of the relief-hole diameters on die elastic deformation are studied. The results show that the elastic deformation of the die is different in the addendum, dedendum, and involute parts of forging gear using different relief-hole diameters. The die elastic deformation increases firstly and then decreases when the relief-hole diameter increases. The tooth portions are of larger elastic deformation and the peak value locates in the addendum. It shows the importance of optimizing the relief-hole diameter to minimize the dimensional inaccuracy of forging gears caused by the die elastic deformation

Снижение погрешностей в системе пресс-штамп и безручьевое профилирование заготовок на прессах

Обоснованы направления повышения точности штамповки на кривошипных прессах путем применения малозатратных конструктивных и технологических решений. Разработаны конструкции устройств, предназначенных для компенсации погрешностей системы пресс-штамп, и показаны возможности безручьевого профилирования заготовок на прессах с повышением точности на окончательных штамповочных операциях.Directions of the rise of precision during die-forging by crank-shaft presses by the way of application of law expenditure designer and technological decision are ground. Designs of facilities for compensation of errors of press-die system are carry out and possibility of shape profiling of billets without die-streams by presses with high precision in finished forging operations are shown

Precision forging

Tato bakalářská práce se věnuje metodám, postupům a možnostem přesného kování. Po úvodní analýze metod zápustkového kování s výronkem obsahuje přehled, rozbor a popis metod kování přesného, včetně technologického zhodnocení s ohledem na technické možnosti, investiční náročnost a očekávaný přínos. Hlavní důraz je kladen na technologické podmínky, technologický postup, konstrukci zápustek a kovacích zařízení.The thesis deals with methods, procedures and possibilities of precision forging. After the initial analysis methods of die forging with collar also comprises an overview, analysis and description of methods of precision forging, including a technological evaluation in view of technical possibilities, investment requirements and expected benefits. The main emphasis is laid on the technological conditions, procedure, on the construction of the dies and forging devices.

Application of computer simulation at optimization of technological parameters of precision die forging

visoke dimenzionalne točnosti i kvalitete površine otkivaka dobivenih kalupnim kovanjem. Istraživanje se provodilo na čelnicima s ravnim zubima s glavinom. Taj je tip strojnog dijela izabran zbog njegove široke primjene u strojarstvu. Oblik takvog otkivka također je pogodan za tehnologiju preciznog kovanja. Čelik za kaljenje 16MnCr5 odabran je kao materijal za proizvodnju kalupnim kovanjem. Simulacija računalom je korisno rješenje za predviđanje odvijanja postupka kovanja i ponašanja materijala u zatvorenoj šupljini kalupa. Numerička simulacije je primijenjena u optimizaciji oblika i dimenzija trupca te promatranja plastičnog tečenja u zatvorenoj šupljini kod kovanja u kalupu. Odgovarajući tok materijala u kalupu, učinkovita plastična deformacija i temperatura kalupnog kovanja procijenjeni su pomoću simulacijskog softvera Simufact.forming. Kako bi se zadovoljili svi zahtjevi vezani za točnost otkivaka dobivenih kalupnim kovanjem potrebno je uzeti u obzir optimizaciju tehnoloških parametara primjenom simulacije računalom.The paper deals with the optimization of technological parameters of precision forging in closed die using computer simulation with the aim to achieve high dimensional accuracy and surface quality of drop forgings. The research has been applied on spur gears with a hub. This type of mechanical part has been chosen because of its wide application in machine industry. Shape of this drop forging is suitable for the precision forging technology, as well. Case hardening steel 16MnCr5 has been selected as a common material used for drop forging production. Computer simulation is a useful solution for prediction of the forging process development and material behaviour in closed die cavity. The numeric simulation has been used for the optimization of billet shape and dimensions and observation of plastic flow in closed die cavity at warm die forging. Suitability of material flow in die cavity, effective plastic strain and temperature of drop forging have been evaluated by means of simulation software Simufact.forming. To meet all requirements on accuracy of drop forgings it is necessary to take into consideration optimization of technological parameters using computer simulation

Investigating dimensional and geometrical accuracy of isothermally forged blades

Compressor blades are one of the well-known products made of titanium alloys. They are usually manufactured by a forging process followed by a sequence of machining processes. Precision forging eliminates a considerable amount of machining; however, due to the close tolerances, the process should be designed in a manner to meet dimensional and geometrical tolerances as well as the desired mechanical and metallurgical properties. In this paper, effects of two main process parameters, the process temperature and strain rate, on the dimensional and geometrical accuracy of the isothermally forged blades are investigated experimentally. The results are analyzed by the response surface method (RSM). In order to justify the results and have a tool for further studies, a coupled thermo-mechanical finite element method model is developed and verified by the experimental results. The results show that the process temperature and pressing speed and their interaction have a meaningful effect on the thickness error; however, the interaction effect of the process temperature and pressing speed on the twist error is not considerable and moreover the bow error of the forged blades is not significant. Finally, the results show that for a given geometry, by selection of appropriate process parameters, a sound workpiece with acceptable dimensional and geometrical aspects can be manufactured without any need for a die shape compensation

The rationalization of production of magnesium alloy drop forgings using FEM simulation regarding forging process

U radu se opisuje metoda preciznog kovanja u kalupu bez plamena legure magnezija AZ31. U usporedbi s uobičajenom metodom kovanja s plamenom, ova metoda štedi material i energiju. Računalna simulacija tehnološkog postupka kovanja ima važnu ulogu u razvoju naprednih metoda preciznog kovanja. Kovanje legure Mg u zatvorenom kalupu, opisano u ovom radu, verificirano je primjenom programa MSC.SuperForge. Eksperiment kovanja bez plamena otkivka u obliku šipke od legure magnezija AZ31 uspješno je proveden u laboratorijskim uvjetima. Dobiveni otkivak nema nabora ili drugih oštećenja na površini zbog pravilnog izbora temperature kovanja od 400 °C i oblika polu-proizvoda. Postignuti rezultati eksperimenta bit će važni za radnu grupu tehnologa kod uvođenja u proizvodnju kovanja bez plamena otkivaka dobivenih kalupnim kovanjem.In this paper a method of precision die forging without flash of magnesium alloy AZ31 is described. This method brings material and energy savings compared to common method of forging with flash. Computer simulation of technological process of forging has an important role for development of progressive methods of precision die forging. The forging of Mg alloy in closed die described in this paper was verified using program MSC.SuperForge. Experiment of forging without flash of lever-shaped forged piece from magnesium alloy AZ31 was successfully performed at laboratory conditions. Final drop forging has no folds or other defects on its surface, which is confirmed by correct selection of forging temperature 400 °C and semi-product shape. Achieved results of the experiment will be important for working team of technologists at introducing forging without flash regarding non-ferrous drop forgings to production practice

A Study on the Development of Forging Process for Steam Turbine Titanium Blade

When Ti-6Al-4V is used in long steam turbine blades, the main issues are how to improve the fatigue strength as a problem of internal quality and how to forge the thinnest possible blades as problem of dimensional precision. To assure an excellent fatigue strength, it is important to make the two phase fine and equiaxial structure by providing enough plastic deformation in the two phase(α phase/β phase) temperature region. Accordingly, it needs to predict that forging temperature, preform design and forging velocity in forging process. To achieve this end, the two steps forging process was suggested to forge the thin and twisted blades with a precision hammer considering die forces and metal flow. Two steps forging process consists of the flattening forging process and finishing forging process. Process in forging of a 1016mm long steam turbine blade is designed by the finite element method. This study attempts to derive systematic design procedures for process design in the forging. Forging parameters was analyzed in two-dimensional plane-strain simulation and two steps forging process carried out in three-dimensional simulation. Consequently, optimal forging process parameters of long steam turbine blades in Ti-6Al-4V with a high dimensional precision are selected in the hammer die forging.ABSTRACT ⅰ 기호설명 ⅲ List of Tables ⅳ List of Figures ⅴ 1. 서론 1 1.1 연구 배경 1 1.2 연구 동향 1 1.3 연구 목적 2 2. 이론적 배경 4 2.1 티타늄 합금(Ti-6Al-4V)의 소재특성 4 2.1.1 물리적 성질 5 2.1.2 기계적 성질 6 2.2 강소성 유한요소법 7 3. 티타늄 블레이드의 단조공정 11 3.1 티타늄 합금(Ti-6Al-4V)의 단조특성 11 3.2 블레이드의 단조공정 13 4. 시뮬레이션 16 4.1 시뮬레이션의 개요 16 4.2 2차원 시뮬레이션 16 4.2.1 해석조건 16 4.2.2 시뮬레이션 및 해석결과 22 4.3 3차원 시뮬레이션 34 4.3.1 3차원 시뮬레이션의 개요 34 4.3.2 직접 단조법 40 4.3.3 2단계 단조법 45 4.3.4 직접 단조법과 평면 단조법의 비교 55 4.4 시뮬레이션 결과 및 고찰 60 5. 결론 61 6. 참고문헌 6

Повышение геометрической точности осесимметричных поковок на основе метода функций Ляпунова

Разработана новая методика повышения геометрической точности поковок для горячей штамповки, в основе которой лежит минимизация целевой функции в виде позинома, связывающего геометрическую точность с величинами интенсивностей напряжений на поверхностях и в «жестких» зонах поковки. Метод функций Ляпунова применен для исследования устойчивости пластического равновесия в зонах концентрации напряжений после повышения геометрической точности поковки. Выполнен анализ теплового и силового режимов работы штампа. Выявлен преобладающий вид износа для каждой из поверхностей ручья.A new technique was developed for increasing the geometrical precision of axially symmetric forged pieces for hot forging. The technique is based on minimization of a posynomial efficiency function that connects the geometrical precision with stress intensity values at the surfaces and rigid zones of a forged piece. The Lyapunov functions method is implemented for investigation of plastic equilibrium in the stress concentration zones after increasing the geometrical precision of the forged piece. Thermal and stress conditions of die operation were investigated. The dominating deterioration was detected for each surface of the die impression