Wyniki 1-6 spośród 6 dla zapytania: authorDesc:"Mária KAPUSTOVÁ"

the analysis of closed-die forging process with the help of computer simulation

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The paper is focused on analysis of materials behaviour at die filling during closed die forging. The analysis was done for forging of part for transmission gear with simulation software SuperForge. The analysis enabled to optimize forging process especially from the point of view of elimination of the flash creation. The analysis allowed the verification of forging tools design for production o[...]

Verification of bulk metal forming numerical model

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Numerical models of metal forming based on finite elements method can lead to excellent results, but it is necessary to verify them by experimental results. The simple way as to verify numerical result is to compare them with experimental result. Bulk forming leads to grain boundaries deformation. The value of strain is very simple to obtain by stereology, more precisely - by measurement of grai[...]

The Research of Forgeability of Magnesium Alloy at Warm Forming Temperatures DOI:10.15199/24.2016.9.8


  Badania podatności do kucia stopów magnezu w podwyższonych temperaturach The presented contribution is aimed at research of temperature influence on workability of a selected magnesium alloy at temperature interval for warm forming. The magnesium alloy type AZ31 was selected for experimental purposes. The mentioned alloy is used for production of drop forgings. In order to consider forgeability, Židek´s pressure test at warm conditions was selected and used as technological test. The author of mentioned test recommends cylinder shaped test sample with four notches. For magnesium alloy AZ31 hot forming at temperature interval from 250°C to 425°C is recommended. The pressure tests were conducted within the temperature interval of 200-350°C, i. e. at temperatures belonging to lower limit of recommended temperature interval, in order to acquire as much information as possible on behaviour, plasticity and formability of magnesium alloy at lower forming temperatures. Zakres niniejszej pracy dotyczy wpływu temperatury na kowalność stopów magnezu. Wybrany do badań Stop AZ31 jest kształtowany w procesach kucia, czego efektem jest wytwarzanie odkuwek o zróżnicowanych kształtach. Biorąc pod uwagę kowalność do badań, wybrano metodę testu ciśnieniowego w podwyższonej temperaturze. Autorzy tej metody zalecają badania próbek w kształcie walca z czterema karbami. Dla badanego stopu zaleca się temperaturę obróbki plastycznej w przedziale 250°C do 425°C. Test ciśnieniowy przeprowadzono w zakresie temperatury od 200-350 °C, ze względu na analizę zachowania się stopu podczas kształtowania w temperaturze z dolnego zalecanego zakresu przeróbki plastycznej. Key words: warm forming, forgeability, test pressure, magnesium alloy, appearance of cracks in notches Słowa kluczowe: kształtowanie w podwyższonej temperaturze, podatność do kucia, test ciśnieniowy, stopy magnezu, pękanie w karbie Introduction. Drop forgings made of nonferrous metals have been increasingly app[...]

The Influence of Temperature and Strain Rate on Flow Stress of Steel 10CrMo9-10 used for Drawing of Tubes DOI:10.15199/24.2017.8.20


  Introduction. The flow stress curves built by the tensile or pressure tests are important for accurate calculation of forming pressures, forming forces and deformation work in individual moulding operations. The calculated techno lection of suitable forming machines as well as the proper dimensioning of the forming tools. The flow stress curves of the refractory materials su itable for seamless tubes are important for the preparatory phase of computer simulation of the cold drawing process. Correctly selected input parameters of the cold drawing of pipes affect the accuracy of the computer simulation results. It is therefore necessary to constantly complement the si mulation software database of materials with the flow stress curves of the materials used for the production of seamless tubes. Determination of the courses of flow stress curves also allows defining the limit strain by using the Ludwik -Holomon equation [1-4]. Examined material description. Creep-resistant 15 313 steel (10CrMo9-10, W. Nr. 1.7380) is a low-alloy steel cha racterized by both good hot forming and workability. The steel is designed for elevated temperatures at simultaneous higher pressures. It exhibits resis[...]

The importance of FEM simulation in design of a forming tool for test sample preparation to measure solder wettability DOI:10.15199/24.2019.8.6


  Introduction. The shape of a test sample is very important in the evaluation of solder wettability, as the initial shape of the sample affects the final shape of a drop on the substrate surface. Theoretically it can be derived that a ballshaped solder sample is ideally shaped as the ball represents a complete non-wettability of the substrate surface. In a case that the surface is completely non-wetting, a solder remains on the surface in a form of the ball. Several experimental methods are used to determine the wettability and spreading of solders in a liquid state. At present, in research as well as in practice, the goniometric method of wettability measurement is most commonly used. The advantage of this method is that the wettability tests can be performed using a small amount of solder. Moreover, testing at high temperatures is possible and the ball is the most advantageous solder form [7, 8, 10]. In order to achieve higher accuracy of the goniometric method of the solder wettability measurement, efforts have been made to solve this issue, and the result of these efforts was the construction design of the forming tool for the test sample preparation to measure the solder wettability. Description of the test sample preparation tool. The designed solder test sample for the goniometric method of wettability measurement will have a shape of the ball with a diameter of 5 mm. A special tool will be used for the ball manufacture. It consists of two mutually symmetrical parts that hav[...]

Theoretical analysis of tube drawing process DOI:10.15199/24.2019.8.2


  Introduction. The production of precise seamless tubes is a complex problem because it is a complex process involving a lot of factors influencing the production processes and subsequent properties of drawn tubes. There are factors related to preparation of an initial material by continuous casting, hot forming of a pre-tube, cold forming of a tube connected with deformation strengthening, as well as the intermediate and final heat treatment operations. Due to this complexity, the paper is focused only on some problems of cold tube drawing process. Tube drawing [1-7]. During tube drawing a hot-rolled pre-tube is drawn through a die and its outer diameter is reduced. During fixed plug drawing not only the outer diameter of a tube is reduced but also its wall thickness. A coefficient of tube elongation λ is the drawing process characteristic. The λ coefficient can be determined from the law of volume constancy: ( ) ( ) r r r o o o r o o r D s s D s s S S L L - - λ = = = ⋅ ( 1) where: Lo, So, Do, so - length, cross section area, diameter and wall thickness of a tube before drawing, respectively, while Lr, Sr, Dr, sr - length, cross section area, diameter and wall thickness of a tube after drawing, respectively. At drawing with more than one draw, the total coefficient of elongation is detemined as: c n λ =λ ⋅λ ⋅λ ⋅ ⋅λ 1 ..... 2 3 ( 2) where: λc - total coefficient of elongation, λ1, λ2, λ3, λn - coefficient of elongation after the first, second, third and n-th draw, respectively. The tube drawing is divided into: - tube sinking - free tube drawing, - fixed plug drawing - with cylindrical or shaped plug, - floating plug drawing. The paper is focused on fixed plug drawing. Stress-strain states at fixed plug drawing. A schematic representation of stress and strain states in the three subsequent areas of the deformation[...]

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