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1
Content available Evaluation of Structural Powder Steel Properties after High-Temperature Thermomechanical Treatment and Finish Turning
Leksycki Kamil, Feldshtein Eugene, Maruda Radosław, Dyachkova Larisa, Szczotkarz Natalia, Zverko Alexandra
Advances in Science and Technology. Research Journal
|
2024
|
Vol. 18, no 1
26--35
EN
High-temperature thermo-mechanical processing (HTTMP) is a combination of plastic deformation and heat treatment operations. Such action makes it possible to increase metal mechanical properties resulting from both mechanical strengthening and heat treatment. As a result, it is possible to achieve high complex of operating characteristics of different types of steel and other alloys. However, there is a lack of information on the applicability of HTTMP of powder steel. These types of steel are very effective substitutes for traditional structural steel but are characterized by poor mechanical properties. This study considers the possibility of using HTTMP for powder steel frame additionally infiltrated by bronze with MoS2 addition to increase mechanical properties of the materials studied. Steel infiltrated, infiltrated and then hardened, infiltrated and then HTTMP treated with strain rates of 30, 50 and 70% were compared. The microstructural properties and hardness of the materials before machining were studied as well as the cutting forces and surface topography of those materials after turning with AH8015 carbide inserts. Cutting forces tests were realized with vc = 157 m/min, f = 0.25 mm/rev and ap = 0.25 mm. Surface topography tests were carried out with vc = 157 m/min, f = 0.25 mm/rev and ap = 0.25 mm. Constant cutting parameters were used to eliminate the effects of rest factors. It was found that the lowest cutting forces (Fc, Fp and Ff), surface roughness parameters (Sa and Sq) and small areas with single high peaks on the machined surface were obtained for infiltrated powder steel with subsequent HTTMP machining under 50% strain rate.
2
Content available Influence of Isothermal Heating Time on the Disappearance of Strain Hardening in High-Manganese TRIPLEX Type Steels
Sozańska-Jędrasik L., Mazurkiewicz J., Borek W.
Archives of Metallurgy and Materials
|
2018
|
Vol. 63, iss. 4
2023--2030
EN
The paper presents the results of the effect of isothermal heating time on the disappearance of strain hardening (the softening degree) of the studied high-manganese TRIPLEX type steels at a temperature of 900 and 1000°C. In order to determine the kinetics of recrystallization of austenite plastically deformed for selected steels, hot compression tests with draft ε = 0.2 were made. The presented results reveal that the complete recrystallization of austenite needs long isothermal heating times. In industrial conditions, such long times are not used, therefore in the initial rolling passages, the time required for half recrystallization of austenite t0.5 is often used. The total disappearance of the strain hardening, completion of the recrystallization of austenite tested high-manganese X98 and X105 TRIPLEX type steels isothermal heating time requires far more than 200 s. The increase of the deformation temperature is a factor influencing the acceleration of the disappearance of strain hardening.
3
Content available Multiphase Ausformed Austempered Ductile Iron
Soliman M., Palkowski H., Nofal A.
Archives of Metallurgy and Materials
|
2017
|
Vol. 62, iss. 3
1493--1498
EN
Ductile iron was subjected to a total true strain (φt) of 0.3 either by applying φt in the austenite region or by apportioning it through applying a true strain of 0.2 in the austenite region before quenching to austempering temperature (TA) of 375°C, where a true strain of 0.1 is applied (ausforming). Additionally, two types of matrices were produced in the ductile iron, namely ausferritic and ferritic-ausferritic matrices. The ferrite is introduced to the matrix by intercritical annealing after austenitization. Dilatometric measurements as well as microstructure examination showed a fast ausferrite transformation directly after applying φA and that the introduction of ferrite to the matrix resulted in a remarkable acceleration of the ausferrite formation. The transformation kinetics, microstructure evolution, hardness and compression properties are studied.
4
Content available remote Development of the low temperature bainite
Soliman M., Palkowski H.
Archives of Civil and Mechanical Engineering
|
2016
|
Vol. 16, no. 3
403--412
EN
The possibility of obtaining steels with nano-size plates of bainitic-ferrite by isothermal transformation at low temperature is set forth. These steels have attracted great interest due to their excellent combination of strength, toughness, and ductility. In further investigations, the composition and the processing methods of these steels are adjusted to: (1) Optimize their technological properties with regard to mechanical behavior, weldability and formability. (2) Accelerate their transformation kinetics. (3) Minimize/eliminate the need for expensive alloying elements. (4) Lower the martensite start temperature (Ms) either by thermo-mechanical processing or by modifying the bainite transformation stage. Suppressing Ms is of particular importance in steels with relatively low carbon content; that is to allow for bainite formation at low temperature. Furthermore, many reports addressed some technological aspects like fatigue behavior, wear resistance and bake hardenability. This article presents an overview of the so far studied alloying strategies and processing methods adopted for developing the low temperature bainite together with addressing some examined technological themes. The paper is engrafted in relevant sections with new results of the authors that are not published before. One of these results is that the low temperature bainite possesses a very strong bake hardening potential.
5
Content available Symulacja numeryczna i symulacja fizyczna w skali laboratoryjnej zmian mikrostruktury austenitu w procesie walcowania blach ze stali konstrukcyjnej wielofazowej
Kuziak R., Pidvysots'kyy V., Zalecki W., Molenda R., Łapczyński Z.
Prace Instytutu Metalurgii Żelaza
|
2012
|
T. 64, nr 1
17-23
PL
Na przykładzie stali CP opisano proces budowy kompleksowego modelu matematycznego obejmującego reologię odkształcanego materiału oraz zmiany zachodzące w strukturze austenitu w procesach obróbki plastycznej. Opracowany model matematyczny uwzględnia zależność kinetyki zmian strukturalnych od wielkości początkowego ziarna austenitu, wartości odkształcenia zastępczego i prędkości odkształcenia oraz od temperatury i czasu. Dzięki temu możliwe jest jego implementowanie do programów numerycznych symulujących płynięcie plastyczne materiału i transport ciepła wykorzystujących metodę elementów skończonych. Model matematyczny rozwoju struktury opracowano w oparciu o analizę wyników badań przeprowadzonych z wykorzystaniem symulatora Gleeble 3800. Modele opracowane w badaniach implementowano w komputerowym systemie wspomagającym projektowanie i realizację półprzemysłowego walcowania na gorąco, zaś wyniki przeprowadzonych symulacji z wykorzystaniem tego systemu przedstawione zostaną w prezentacji Pietrzyka i Raucha [1]. W artykule przedstawiono również możliwości symulacji fizycznej procesu walcowania na gorąco blach z wykorzystaniem symulatora Gleeble 3800. Metoda ta pozwala bardzo efektywnie wyznaczyć parametry procesu walcowania dla uzyskania pożądanej struktury blach.
EN
The paper presents development of rheological and microstructural model for evolution of austenite in a multi - phase or Complex Phase (CP) steel subject to thermo-mechanical processing. The model accounts for the effect of prior austenite grain size, effective strain and strain rate, and also temperature and time on the kinetics of microstructural changes and phase transformations. This feature allows its implementation in the numerical models based on FEM for simulation of plastic flow and heat transfer. The microstructure evolution model was developed based upon plastometric tests conducted with Gleeble 3800 simulator. The developed models were implemented into hybrid expert system prepared by Pietrzyk and Rauch to be used for designing hot rolling technology for semi-industrial simulation [1]. The capability of physical simulation using simulator Gleeble 3800 to develop or optimize the parameters of the rolling was also demonstrated in the paper. The method allows the effective determination of the thermo-mechanical processing parameters to achieve the desired microstructure.
6
Content available remote Designing of cooling conditions for Si-Al microalloyed TRIP steel on the basis of DCCT diagrams
Grajcar A., Zalecki W., Kuziak R.
Journal of Achievements in Materials and Manufacturing Engineering
|
2011
|
Vol. 45, nr 2
115--124
EN
Purpose: The aim of the research presented in the paper is to design the cooling routes after plastic deformation ensuring the multiphase structure with a high fraction of retained austenite on the basis of DCCT diagram for a new-developed Si-Al microalloyed TRIP steel. Design/methodology/approach: The CCT and DCCT diagrams were developed. Eight variants of the thermomechanical processing were designed on the basis of the DCCT diagram. The thermomechanical processing consisted of a multi-stage compression and various cooling strategies in the γ→α transformation range and isothermal holding temperature at a bainitic transformation region. Findings: The usefulness of DCCT diagram for designing the thermomechanical processing conditions for TRIP steels was demonstrated. The fraction of ferrite and retained austenite are highly dependent on a cooling path applied in the γ→α transformation region and a fraction of retained austenite especially on the isothermal holding temperature. The highest fraction of retained austenite as irregular grains located in a ferritic matrix and fine islands or interlath regions in bainitic regions were obtained at temperature of 400 and 450°C. Research limitations/implications: To determine precisely a fraction of retained austenite, the X-ray investigations has to be applied additionally to the image analysis. Practical implications: The designed cooling conditions are of great importance for the thermomechanical strategy for manufacturing the advanced high strength TRIP steels. Originality/value: The thermomechanical processing was carried out for a new group of TRIP steels with Si partially replaced by Al and containing microadditions of Nb and Ti.
7
Content available Podstawy teoretyczne i doświadczalne modelowania operacji obróbki cieplno-mechanicznej wałów o małej sztywności
Draczew O., Świć A., Taranenko W., Taranenko G.
Postępy Nauki i Techniki
|
2010
|
nr 5
55-70
PL
W artykule przedstawiono podstawowe założenia, umożliwiające modelowanie operacji obróbki cieplno-mechanicznej wałów o małej sztywności. Pokazano schematy realizacji metod obróbki cieplno-mechanicznej, wyniki badań odkształceń i naprężeń przy obciążeniu osiowym, charakterystyki temperatury nagrzewania i chłodzenia, odkształceń i naprężeń. Przedstawiono przykład urządzenia do sterowania procesem odkształceń plastycznych wału o małej sztywności.
EN
The paper introduces scientific principles of modeling the thermo-mechanical processing of non-rigid shafts. The schemes of realization of the thermo-mechanical processing of non-rigid shafts, the results of research of strains and stresses during axial tension and temperature profiles while heating and cooling were presented. The example of device for controlling the process of non-rigid shafts’ elastic deformation was introduced.
8
Content available Modelowanie układu dynamicznego obróbki cieplno-mechanicznej wałów o małej sztywności
Draczew O., Świć A., Taranenko W., Taranenko G.
Postępy Nauki i Techniki
|
2010
|
nr 5
71-84
PL
W artykule rozpatrzono metodologię opracowania modeli matematycznych obróbki cieplno-mechanicznej wałów małej sztywności. Przedstawiono analizę modeli sterowania: odkształceniami sprężysto-plastycznymi, niezmiennością obciążeń zewnętrznych i procesów zdejmowania obciążeń. Do analizy jakościowej procesów opracowano modele matematyczne układu dynamicznego obróbki cieplno-mechanicznej wałów o małej sztywności. Przedstawiono proste modele trzyelementowe, opisujące tylko naprężenia i odkształcenia. Przeanalizowano również bardziej złożone modele matematyczne, opisujące niesprężyste ciała sztywne.
EN
The methodology of formulating mathematical models of thermo-mechanical processing of non-rigid shafts was presented in the article. The analysis of models of control was introduced for following parameters: the elastic and plastic deformation, the invariability of external loads and the processes of loads removal. The mathematical model of dynamic system of thermo-mechanical processing of non-rigid shafts was built for qualitative analysis of processes. Simple three-element models were introduced, describing only strains and stresses. More detailed mathematical models describing also inelastic solid bodies were analyzed as well.
9
Content available remote Morphological features of retained austenite in thermo-mechanically processed C-Mn-Si-Al-Nb-Ti multiphase steel
Grajcar A.
Journal of Achievements in Materials and Manufacturing Engineering
|
2010
|
Vol. 39, nr 1
7-18
EN
Purpose: The aim of the paper is to determine the influence of isothermal bainitic transformation temperature on morphological features and a fraction of retained austenite in a new-developed thermo-mechanically processed C-Mn-Si-Al-Nb-Ti multiphase steel. Design/methodology/approach: The thermo-mechanical processing was realized in a multi-stage compression test by the use of the Gleeble thermomechanical simulator. The steel was isothermally held for 600 s in a bainitic transformation temperature range of 250 to 500°C. A fraction and stereological parameters of retained austenite were determined by a computer image analyser using an optical microscope. The details of the retained austenite morphology were revealed in a scanning electron microscope and using EBSD technique. Findings: The maximum fraction of retained austenite (above 14%) was obtained for the temperatures of isothermal bainitic transformation from 400 to 450°C. Below 350°C, the largest grains of retained austenite located in a ferritic matrix transform to martensite and its fraction estimated by the use of computer image analysis is too high compared to X-ray investigations. Blocky, irregular grains located in a ferritic matrix are a main structural constituent of retained austenite in a temperature range up to 350°C. Increasing the isothermal holding temperature to a range of 400-450°C results in increasing a fraction of fine blocky and layer regions of the ă phase. Research limitations/implications: To describe in detail morphological features of retained austenite in fine-grained multiphase structures, a combination of different methods characterized by various resolution is necessary. Practical implications: The revealed morphological features of retained austenite are of great importance for mechanical stability of this phase during cold straining, affecting mechanical properties of advanced TRIP-assisted steels. Originality/value: Combined colour etching, scanning electron microscopy and EBSD (Electron Backscattered Diffraction) methods were applied to characterize retained austenite in a modern group of thermomechanically processed TRIP steels with Nb and Ti microadditions.
10
Content available remote Microstructure forming processes of the 26Mn-3Si-3Al-Nb-Ti steel during hot-working conditions
Dobrzański L. A., Borek W.
Journal of Achievements in Materials and Manufacturing Engineering
|
2010
|
Vol. 40, nr 1
25-32
EN
Purpose: The influence of hot-working conditions on microstructure evolution of new-developed 26Mn-3Si-3Al-Nb-Ti high-manganese steel was investigated. Design/methodology/approach: The force-energetic parameters of hot-working were determined in continuous and multi-stage compression test performed in temperature range of 850 to 1100°C using the Gleeble 3800 thermomechanical simulator. Evaluation of processes controlling work-hardening were identified by microstructure observations of the specimens compresses to the various amount of deformation (4x0.29, 4x0.23 and 4x0.19). Findings: The investigated steel is characterized by high values of flow stresses from 250 to 430 MPa. Increase of flow stress along with decrease of compression temperature is accompanied by translation of ĺmax strain in the direction of higher deformation. Results of the multi-stage compression proved that applying the true strain 4x0.29 gives the possibility to refine the austenite microstructure as a result of dynamic recrystallization. In case of applying the lower deformations 4x0.23 and 4x0.19, the process controlling work hardening is dynamic recovery and a deciding influence on a gradual microstructure refinement has statical recrystallization. Research limitations/implications: To determine in detail the microstructure evolution during industrial rolling, the hot-working schedule should take into account real number of passes and higher strain rates. Practical implications: The obtained microstructure – hot-working relationships can be useful in the determination of power-force parameters of hot-rolling and to design a rolling schedule for high-manganese steel sheets with fine-grained austenitic structures. Originality/value: The hot-deformation resistance and microstructure evolution in various conditions of hot-working for the new-developed high-manganese 26Mn-3Si-3Al-Nb-Ti austenitic steel were investigated.
11
Wpływ parametrów wyżarzania ujednorodniającego i składu chemicznego na plastyczność stopów z układu Fe-Al z fazami międzymetalicznymi
Jabłońska M., Bernstock-Kopaczyńska E.
Hutnik, Wiadomości Hutnicze
|
2010
|
Vol. 77, nr 8
397-400
PL
W artykule przedstawiono badania prowadzone pod kątem zdolności kształtowania stopów z układu Fe-Al na drodze obróbki cieplno-plastycznej. Analizowano wpływ wyżarzania ujednorodniającego i składu chemicznego na plastyczność. Po odlaniu i wyżarzaniu stopy poddano próbie osiowosymetrycznego ściskania na symulatorze Gleeble w temperaturze 900 i 1000 °C z prędkością odkształcenia 0,1 s-1 do wartości odkształcenia 1,0. Analizowano procesy zachodzące podczas odkształcenia.
EN
The alloys based from the Fe-Al system with intermetallic phases belong to materials for high-temperature applications with good creep resisting and mechanical properties. Limitation on the capacity for a broad their application as an alternative to expensive alloy steels of specific properties, is their insufficient plasticity, which is a factor inhibiting further their development as constructional materials. In this paper research has been conducted on the capacity for forming alloys from the Fe-Al system, via thermomechanical processing. The influence of homogenizing parameters and chemical composition on the plasticity of this materials was analyzed. After casting and annealing, alloys were subjected to axial-symmetric compression in the Gleeble simulator in the 900 °C and 1000 °C at 0.1 s-1 strain rates. The processes which take place during deformation have been analyzed.
12
Content available remote Flow Stress Numerical Modeling for Large Strain Deformation in Magnesium
De Pari L., Jr, Misiolek W. Z., Forsmark J. H., Luo A. A.
Computer Methods in Materials Science
|
2010
|
Vol. 10, No. 2
108-129
EN
An existing flow stress model proposed by Barnett was examined with as-cast homogenized AZ31 compression test data for a range of temperatures (250-450 centigrade) and strain rates (0.001-20s-1) from literature to verify the applicability of the model to direct extrusion of AZ31. The model was successful in predicting the hardening region of the flow curve but was unable to simulate the sizable softening component of the flow curve that as-cast homogenized magnesium alloys tend to have before failure. In order to correct this shortcoming, an empirical softening expression was developed with the same range of temperatures and strain rates. This modified flow stress model was then implemented into the finite element software package DEFORMTM 3-D to examine the hot-direct extrusion of hollow AZ31 automobile structural components fabricated using a port-hole die.
PL
Istniejący model naprężenia uplastyczniającego zaproponowany przez Barnetta został przeanalizowany używając danych z literatury dla odlanego i homogenizowanego stopu AZ31 poddanego próbom ściskania w zakresie temperatur od 250 do 450 centigrade i prędkości odkształcenia od 0.001 do 20 s-1. Analizę te przeprowadzono w celu zwerifikowania czy model ten nadaje się do zastosowania do procesu wyciskania współbieżnego stopu AZ31. Model ten sprawdził się w przewidywaniu krzywej umocnienia lecz nie był w stanie przewidzieć znaczącego zmiękczenia materiału typowego dla odlanego i homogenizowanego stopu magnezu tuz przed pęknięciem. W celu poprawienia tego limitującego faktu opracowano poprawkę dla tego zakresu temperatur i prędkości odkształcenia. Ten zmodyfikowany model naprężenia uplastyczniającego został następnie zastosowany w programie elementów skończonych DETORM™ 3-D w celu analizy wy ciskania współbieżnego na gorąco przez matryce mostkowa profilu ze stopu AZ31.
13
Content available remote Effect of isothermal bainitic transformation temperature on retained austenite fraction in C-Mn-Si-Al-Nb-Ti TRIP-type steel
Grajcar A., Krztoń H.
Journal of Achievements in Materials and Manufacturing Engineering
|
2009
|
Vol. 35, nr 2
169-176
EN
Purpose: The aim of the paper is to determine the influence of isothermal bainitic transformation temperature on a fraction of retained austenite for a new-developed C-Mn-Si-Al-Nb-Ti TRIP-type steel. Design/methodology/approach: The thermo-mechanical processing was realized in a multi-stage compression test by the use of the Gleeble 3800 thermomechanical simulator. The steel was subjected to six variants of processing with an isothermal bainitic transformation temperature in a range from 250 to 500°C. Identification of phase composition was achieved using microstructure observations and X-ray diffraction. To determine the fraction of retained austenite the Rietveld method was applied. Findings: The maximum fraction of retained austenite equal up to 16% can be obtained for the temperatures of isothermal bainitic transformation from 400 to 450°C, while the maximum carbon content in the ă phase equal 1.5 wt.% is present at the temperature of 350°C. Below 350°C due to high Ms temperature, the largest grains of retained austenite located in the ferritic matrix transform to marteniste. In a temperature range from 350 to 450°C, the Msă temperature has a negative value, stabilizing the retained austenite. Research limitations/implications: To determine in detail the influence of isothermal bainitic transformation conditions on a fraction of retained austenite, the knowledge of the effect of isothermal holding time is also important. Practical implications: The obtained microstructures and especially retained austenite fraction dependent on an isothermal bainitic transformation temperature can be useful in optimization of thermo-mechanical processing conditions of C-Mn-Si-Al TRIP-type steels. Originality/value: Combined colour etching and X-ray diffraction methods were applied for microstructure identification of modern group of TRIP steels predicted to use in the automotive industry.
14
Content available remote Corrosion behaviour of Fe-Mn-Si-Al austenitic steel in chloride solution
Opiela M., Grajcar A., Krukiewicz W.
Journal of Achievements in Materials and Manufacturing Engineering
|
2009
|
Vol. 33, nr 2
159-165
EN
Purpose: The aim of the paper is to investigate the corrosion behaviour of the new-developed high-manganese austenitic steel in 0.5n NaCl solution. Design/methodology/approach: The steel used for the investigation was thermomechanically rolled and solution heat-treated from a temperature of 850°C. Corrosion resistance of investigated steel was examined using weight and potentiodynamic methods. In the weight method, the specimens were immersed in the prepared solution for 24h. In the potentiodynamic method, anodic polarization curves with a rate of potential changes of 1 mV/s in the anodic direction were registered. After the current density being equal 1 mA/cm2 was achieved, the direction of polarization has been changed. Basing on the registered curves, the pitting potential, repassivation potential, polarization resistance and corrosion current were determined. Findings: It was found that the steel is characterized by a partially recrystallized austenitic microstructure with numerous annealing twins and slip bands. According to the results of potentiodynamic analyses it was found that the samples of examined steel show poor corrosion resistance in the NaCl solution. The observed corrosion pits are related to the chemical composition. It is connected with the high dissolution rate of Mn and Fe atoms in NaCl solution. Fractographic analyses of samples revealed corrosion products on their surface in a form of pits with diversified size. Research limitations/implications: To investigate in more detail the corrosion behaviour of high-manganese steel, the investigations should include steels with a wider Al concentration. Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of a modern group of high-manganese austenitic steels. Originality/value: The corrosion behaviour in chloride solution of a new-developed Fe-Mn-Si-Al steel was investigated.
15
Content available remote Microstructure evolution of high-manganese steel during the thermomechanical processing
Dobrzański L. A., Grajcar A., Borek W.
Archives of Materials Science and Engineering
|
2009
|
Vol. 37, nr 2
69-76
EN
Purpose: The aim of the paper is to determine the influence of hot-working conditions on microstructure evolution of new-developed high-manganese austenitic steel. Design/methodology/approach: The hot-working behaviour was determined in continuous and multi-stage compression tests performed in a temperature range of 850 to 1100°C by the use of the Gleeble 3800 thermomechanical simulator. The processes controlling work hardening and removing it were identified by microstructure evolution observations in successive stages of compression with the amount of true strain 4x0.29, 4x0.23 or 4x0.19. Findings: The investigated steel is characterized by high values of flow stresses from 250 to 450 MPa. Increase of flow stress along with decrease of compression temperature is accompanied by translation of εmax strain in the direction of higher deformation. Results of the multi-stage compression proved that applying the true strain 4x0.29 gives the possibility to refine the austenite microstructure as a result of dynamic recrystallization. In case of applying the lower deformations 4x0.23 and 4x0.19, the process controlling work hardening is dynamic recovery and a deciding influence on a gradual microstructure refinement has statical recrystallization. Research limitations/implications: To determine in detail the microstructure evolution during industrial rolling, the hot-working schedule should take into account real number of passes and higher strain rates. Practical implications: The obtained σ-ε curves can be useful in determination of power-force parameters of hot-rolling and to design a rolling schedule ensuring a fine-grained microstructure of high-manganese steel products. Originality/value: The microstructure evolution in various conditions of hot-working for the new-developed high-manganese Mn-Si-Al-Nb steel was determined.
16
Content available remote Thermo-mechanical processing of high-manganese austenitic TWIP-type steels
Grajcar A., Borek W.
Archives of Civil and Mechanical Engineering
|
2008
|
Vol. 8, no 4
29-38
EN
The high-manganese austenitic steels are an answer for new demands of automotive industry conceming the safety of passengers by the use of materials absorbing high values of energy during collisions. The chemical compositions of two high-manganese austenitic steels containing various Al and Si concentrations were developed. Additionally, the steels were microalloyed by Nb and Ti in order to control the grain growth under hot-working conditions. The influence of hot-working conditions on recrystallization behaviour was investigated. On the basis of initial investigations realized by hot upsetting the thermo-mechanical conditions resulting in a fine-grained structure were designed. The [...] curves and identification of thermally activated processes controlling work-hardening by the use of the Gleeble simulator were determined. It was found that the thermo-mechanical treatment conditions influence a phase composition of the investigated steels after solution heat treatmenl.
PL
Wysokomanganowe stale austenityczne stanowią odpowiedź dla nowych żądań przemysłu motoryzacyjnego dotyczących bezpieczeństwa pasażerów przez zastosowanie materiałów absorbujących dużą ilość energii w warunkach kolizji. Opracowano składy chemiczne dwóch wysokomanganowych stali austenitycznych zawierających różne stężenie Al i Si. Dodatkowo, w celu kontroli rozrostu ziaren w warunkach obróbki plastycznej na gorąco stale zawierają mikrododatki Nb i Ti. Zbadano wpływ warunków obróbki plastycznej na gorąco na przebieg rekrystalizacji. Na podstawie badań wstępnych zrealizowanych przez spęczanie na gorąco zaprojektowano warunki obróbki cieplno-mechanicznej prowadzące do uzyskania drobnoziarnistej struktury. Przy zastosowaniu symulatora Gleeble wyznaczono krzywe [...] oraz aktywowane cieplnie procesy kontrolujące umocnienie odkształceniowe. Stwierdzono, że warunki obróbki cieplno-mechanicznej mają wpływ na skład fazowy badanych stali po przesycaniu.
17
Content available remote Manufacturing of mass-scale products from structural microalloyed steels in integrated production lines
Adamczyk J.
Journal of Achievements in Materials and Manufacturing Engineering
|
2007
|
Vol. 20, nr 1-2
399-402
EN
Purpose: Technical-economic aspects of the introduction of integrated technological lines for the production of metallurgical products are presented in the work. They have a special importance for microalloyed steels used in different branches of the industry. Design/methodology/approach: The analysis was carried out on a basis of requirements concerning hot-working of microalloyed steels with high mechanical properties produced by the use of the controlled rolling and thermo-mechanical processing. Findings: A modification of some well-known integrated lines consisting in the introduction of the cooling machine between roughing and finishing trains, instead of reheating machine gives a possibility to realize a controlled rolling. Moreover, using retention shields makes possible to manufacture the products by the thermo-mechanical processing. Research limitations/implications: There is a necessity to adjust technological parameters to precise controlling a course of material processes. Practical implications: Development of demands concerning integrated lines enabling to realize the controlled rolling and thermo-mechanical processing. Originality/value: Manufacturing mass-scale products from microalloyed steels in integrated energy-saving lines.
18
Badania wpływu czasu starzenia naturalnego walcówki z przewodowego stopu AlMgSi (seria 6xxx) na własności reologiczne drutów po obróbce cieplno-mechanicznej
Knych T., Mamala A., Smyrak B., Tarasek A.
Rudy i Metale Nieżelazne
|
2005
|
R. 50, nr 2
82-86
PL
W artykule zaprezentowano wyniki badań charakterystyk pełzania drutów ze stopu w gat. 6201 przeznaczonych na napowietrzne przewody elektroenergetyczne. Materiałem wsadowym do procesu ciągnienia jest walcówka w stanie T4 uzyskiwana metodą ciągłego odlewania i walcowania (Continuus Properzi), która charakteryzuje się zróżnicowanym czasem leżakowania, podczas którego zachodzą przemiany strukturalne znamienne dla starzenia naturalnego materiału. Stwierdzono, że charakterystyki pełzania drutu są silną funkcją czasu leżakowania walcówki oraz parametrów obróbki cieplno-mechanicznej. Uzyskane wyniki pozwalają na wnioskowanie praktyczne zmierzające do optymalizacji technologii przetwarzania stopów AlMgSi w warunkach przemysłowych.
EN
The article presents the results of the examination of 6201 alloyed wires creep characteristics used for power overhead lines. A batch to a drawing process is a rod in state T4 obtained by continuous casting and rolling (Continuus Properzi) after various times, during which structural changes typical for material's natural aging process take place. It was observed that wire's creep characteristics is a strong function of duration of material's (rod's) expectation for a process and thermo-mechanic processing parameters. The results presented in the article are a part of a wider program of a research on the influence of rod's natural aging process on wires' utilizable properties. Selected parts of examinations are presented in 1 and 2, this article is a supplement of issued raised in 1 and 2. The results lead to practical conclusions tending towards optimalization of processing technology of AlMgSi alloys in industrial conditions. Very few positions concerning the possibility of shaping AlMgSi wires' rheological properties can we find in literature. Majority of publications is dedicated to the issue of steering material's rheological potential at the stage of exploiting a finished good (a wire hung in span). Articles published by western scientific centers occupied in designing overhead lines and exploiting wires are most frequent. Such articles focus mainly on familiarizing with wires' creep process characteristics, giving exploitation recommendations, creating norms and other restrictions which condition material's rheological potential on the value of 10-year creep deformation. J. R. Harvey and C. A. Roest's articles both present wide range of examinations on various wires' creep processes in various conditions of stress and temperature and show how changing stress during the process of creep may change its character. The most valuable and interesting seem to be examinations on creep processes in conditions of stress and temperature negative gradient which lead to a temporary pause of creep process, which is obviously beneficial if taking the exploitation of a hung wire into consideration. The authors of the articles focus on pure mechanic examinations (change of stress or temperature), aiming at limiting the unprofitable creep process of a finished good. Thus, what seems to be very interesting, presented in this article, is the steering of material 's rheological capability during the stage of shaping its primary properties which may occur by a proper choice of thermal dressing parameters and rod's natural aging process in particular. The work was done within the project "The influence of rod's natural aging on the capability of drawing and shaping properties of AlMgSi wires" sponsored by MNil.
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