Relationship between the structure and physical-mechanical properties of U8A steel subjected to cold plastic deformation by hydrostatic extrusion

2017 ◽  
Vol 53 (10) ◽  
pp. 700-706 ◽  
Author(s):  
E. S. Gorkunov ◽  
S. M. Zadvorkin ◽  
L. S. Goruleva
Author(s):  
Aleksandra Towarek ◽  
Wojciech Jurczak ◽  
Joanna Zdunek ◽  
Mariusz Kulczyk ◽  
Jarosław Mizera

AbstractTwo model aluminium-magnesium alloys, containing 3 and 7.5 wt.% of Mg, were subjected to plastic deformation by means of hydrostatic extrusion (HE). Two degrees of deformation were imposed by two subsequent reductions of the diameter. Microstructural analysis and tensile tests of the materials in the initial state and after deformation were performed. For both materials, HE extrusion resulted in the deformation of the microstructure—formation of the un-equilibrium grain boundaries and partition of the grains. What is more, HE resulted in a significant increase of tensile strength and decrease of the elongation, mostly after the first degree of deformation.


2017 ◽  
Vol 62 (1) ◽  
pp. 223-230 ◽  
Author(s):  
A. Szkliniarz

Abstract This paper presents the possibilities of forming the microstructure as well as mechanical properties and electrical conductivity of Cu-3Ti alloy (wt.%) in thermal and thermomechanical processes that are a combination of homogenising treatment, hot and cold working, solution treatment and ageing. Phase composition of the alloy following various stages of processing it into the specified semi-finished product was being determined too. It was demonstrated that the application of cold plastic deformation between solution treatment and ageing could significantly enhance the effect of hardening of the Cu-3Ti alloy without deteriorating its electrical conductivity. It was found that for the investigated alloy the selection of appropriate conditions for homogenising treatment, hot and cold deformation as well as solution treatment and ageing enables to obtain the properties comparable to those of beryllium bronzes.


2006 ◽  
Vol 114 ◽  
pp. 171-176 ◽  
Author(s):  
Joanna Zdunek ◽  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski

In this work, Al-Mg-Mn-Si alloy (5483) in the as-received and severe plastically deformed states was used. Plastic deformation was carried out by hydrostatic extrusion, and three different true strain values were applied 1.4, 2.8 and 3.8. All specimens were subjected to tensile tests and microhardness measurements. The investigated material revealed an instability during plastic deformation in the form of serration on the stress-strain curves, the so called Portevin-Le Chatelier effect It was shown that grain size reduction effected the character of the instability.


2014 ◽  
Vol 783-786 ◽  
pp. 27-32 ◽  
Author(s):  
Leszek Adam Dobrzański ◽  
Wojciech Borek ◽  
Janusz Mazurkiewicz

Taking into consideration increased quantity of accessories used in modern cars, decreasing car’s weight can be achieved solely by optimization of sections of sheets used for bearing and reinforcing elements as well as for body panelling parts of a car. Application of sheets with lower thickness requires using sheets with higher mechanical properties, however keeping adequate formability. The goal of structural elements such as frontal frame side members, bumpers and the others is to take over the energy of an impact. Therefore, steels that are used for these parts should be characterized by high value of UTS and UEl, proving the ability of energy absorption. Among the wide variety of recently developed steels, high-manganese austenitic steels with low stacking faulty energy are particularly promising, especially when mechanical twinning occurs. Beneficial combination of high strength and ductile properties of these steels depends on structural processes taking place during cold plastic deformation, which are a derivative of SFE of austenite, dependent, in turn on the chemical composition of steel and deformation temperature. High-manganese austenitic steels in effect of application of proper heat treatment or thermo-mechanical treatment can be characterized by different structure assuring the advantageous connection of strength and plasticity properties. Proper determinant of these properties can be plastic deformation energy supply determined by integral over surface of cold plastic deformation curve. Obtaining of high strength properties with retaining the high plasticity has significant influence for the development of high-manganese steel groups and their significance for the development of materials engineering.


2020 ◽  
pp. 93-101
Author(s):  
Serhii Bondarenko ◽  
Olexandr Grydin ◽  
Yaroslav Frolov ◽  
Olga Kuzmina ◽  
Oleksandr Bobukh

Specialists of metallurgy and mechanical engineering are intensively working at materials with controlled properties. In fact, at this stage we are already talking about the design of new materials for the specific tasks of the industry. One of the ways to achieve the regulated mechanical properties of metal products is to use the influence of plastic deformation with its different parameters in individual sections of the deformable material. In this study, we studied the effect of cold rolling on the properties of a strip of aluminum alloy EN AW-1050 with artificially created differences in the deformation parameters in different parts of the cross section of the profile. For this, a pre-shaped sample was prepared by conducting joint cold rolling of a strip of the specified material 420 mm long, 180 mm wide and 2.9 mm thick with a steel profiling tape 80 mm wide and 2 mm thick superimposed on it (length of an aluminum strip and steel profiling tape are the same). As a result of joint deformation, the steel strip rolled into the base metal and changed the geometry of the cross section and the properties of the obtained strip. Next, the obtained strip was subjected to heat treatment and rolled in a duo mill. After rolling, thin samples were made from fabricated flat strips to assess mechanical properties, in particular tensile tests were performed according to ISO 6892-1: 2009 and Brinell hardness tests were performed according to ISO 6506-1: 2014. Experimental studies of cold rolling of strips with profiled cross section of aluminum alloy EN AW-1050 were carried out. The possibility of forming heterogeneous properties in a flat aluminum strip by cold plastic deformation is shown and the maximum average values of the increase in the main indicators of mechanical properties on individual elements of the strip are determined. The maximum difference between the mechanical properties of the thick and thin elements of the profiled strip is observed in the hardness index and reaches 37.5%. The maximum obtained average value of the increase in yield strength and tensile strength is 26% and 18%, which is achieved with true deformation of the thick element of the profiled strip 0.165 and 0.234.


2017 ◽  
Vol 3 (3) ◽  
pp. 79-89
Author(s):  
Yakov D Kogan ◽  
Natal'ya V Bogdanova

Formulation of the problem. Choice of materials and technologies for fabrication mechanical attached fittings (MAF) performed by cold plastic deformation. Method. Theoretical analysis based on mechanical properties fitting and tubing materials. Springback tubing materials shall exceed springback tubing materials. Results. Describes recommendations for materials of contact connections, formed with various methods of plastic deformation.


2014 ◽  
Vol 657 ◽  
pp. 126-131 ◽  
Author(s):  
Tudor Chereches ◽  
Paul Lixandru ◽  
Sergiu Mazuru ◽  
Pavel Cosovschi ◽  
Daniel Dragnea

In our present days numerical simulation became an important tool of engineering. Numerical simulation methods allow quantitative examination of the complex processes and phenomena in the general area of physics and also provide an insight in their dynamic evolution and even can become important tools for the discovery of new phenomena. In essence, the numerical simulation transfer important aspect of physical reality in discrete forms of mathematical description recreates and solves the problems on computer and finally, highlights issues that the analyst required. This modern numerical method approach, attacks the original problems in all their details on a much larger platform with a much smaller number of assumptions and approximations, in comparison to traditional methods. Transposition of the physics problems in the virtual space, governed by the force of computers, numerical simulation - as scientific approach - is becoming increasingly interesting for many fields of research. Basically, by means of numerical simulation are addressed fields such as mechanics deformable solids, fluid mechanics, aerodynamics, biomechanics, astrophysics. Numerical simulations follow a similar procedure to all the scientific approach, which consists in going through several stages, as follows: the phenomenon, the physical model, mathematical model, discrete model, and coding, numerical solution. In the plastic deformation of metals are involved, besides the mechanical properties and some thermal properties because even if the process is applied in the initial state to a cold material, along the process changes occur because of friction between materials and tools and transformation of plastic mechanical work into heat. Basic mechanical properties of the materials are underline through characteristic diagrams of materials obtained in simple tests of traction and compression. These tests were carried out in the Polytechnic University of Bucharest, Romanian Research & Development Institute for Gas Turbines COMOTI, Institute for Calculating and Testing Aero-Astronautic Structures STRAERO, SC UPS PILOT ARM Ltd, and Asachi Technical University of Iasi. To achieve the major objectives of the numerical simulation of the technological process of cold plastic deformation, are incorporated into the physical model three types of surfaces: cylindrical, conical and profiled. The sizes of the initial geometry were established in accordance with the basic dimensions of processed products by this method. For delimiting surfaces to be machined, the addition of grip (the tail) has a reduced diameter. Geometric models provide strength and rigidity needed for safely and accurately processing technology of cold plastic deformation. Geometric models and specimens which had been subjected to tensile tests, compression and hardness were made in the Glass Factory, Chisinau, Moldova.


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