Wyniki wyszukiwania - BazTech

1

Influence of Tempering Temperature on the Abrasive Wear of High-Strength, Martensitic Boron Steel Hardox Extreme

Zemlik Martyna, Konat Łukasz, Grygier Dominika

Tribologia

|

2023

|

nr 1

99--108

EN

The article discusses the microstructural and wear aspects of high-strength, martensitic boron steel Hardox Extreme. It is characterised by a hardness well in excess of 600 HBW and a static tensile strength Rm over 2000 MPa, which provides high resistance under abrasive wear conditions. However, such high mechanical properties reduce the steel's ductility parameters, including impact strength, elongation and area reduction. Examples of components exposed to abrasive wear, including ploughshares, cultivator teeth, excavator buckets or chutes, also require satisfactory resistance to impact wear. Subjecting Hardox Extreme steel to tempering treatments can enhance its performance characteristics by increasing its plastic properties while maintaining satisfactory mechanical indices. Therefore, it was decided to study the tribological properties of Hardox Extreme steel after stress-relieving and low-temperature tempering treatments. In the course of the work carried out, it was shown that with a reduction in hardness from 644 HBW to 508 HBW, it is possible to achieve satisfactory wear indices. The value of the coefficient of relative abrasion resistance kb is equal to 1.36–1.12, respectively, for the as-delivered condition and after tempering treatments at 250°C.

PL

W artykule omówione zostały aspekty mikrostrukturalne i zużyciowe wysokowytrzymałej, martenzytycznej stali z borem Hardox Extreme. Charakteryzuje się ona twardością znacznie przekraczającą wartość 600 HBW i wytrzymałością na statyczne rozciąganie Rm powyżej 2000 MPa, co zapewnia wysoką odporność w warunkach zużycia ściernego. Jednakże tak wysokie własności mechaniczne powodują obniżenie parametrów plastycznych stali, uwzgledniających udarność, wydłużenie i przewężenie. Przykładowe elementy narażone na zużycie ścierne, w tym lemiesze pługa, zęby kultywatora, łyżki koparek czy zsuwnie kosza czerpakowego wymagają także zadowalającej odporności na ścieranie udarowe. Poddanie stali Hardox Extreme zabiegom odpuszczania może wpłynąć na zwiększenie jej cech użytkowych poprzez podwyższenie właściwości plastycznych przy jednoczesnym zachowaniu zadowalających wskaźników mechanicznych. W związku z powyższym zdecydowano się zbadać własności tribologiczne stali Hardox Extreme po przeprowadzeniu za biegów odprężania i niskiego odpuszczania. W toku przeprowadzonych prac wykazano, że przy obniżeniu twardości z 644 HBW do 508 HBW możliwe jest uzyskanie zadowalającej odporności na zużycie ścierne. Wartość współczynnika względnej odporności na zużycie kb wynosi 1,36–1,12, odpowiednio dla stanu dostarczenia i po przeprowadzeniu zabiegów odpuszczania w temperaturze 250°C.

2

The latest innovations in wheat flour milling: a review

Dziki Dariusz

Agricultural Engineering

|

2023

|

Vol. 27, No. 1

147--162

EN

The milling process has evolved over time, employing various techniques to produce flour with different particle sizes and applications. This paper discusses the advancements in the wheat flour milling process and examines their impact on flour quality. The concept of wheat milling value is also introduced, which refers to the ability of wheat to produce flour with desirable properties and high yield. The importance of wheat cleaning in the milling process is highlighted, along with technological advancements such as color sorting machines and debranning of wheat grains before grinding, which facilitate efficient cleaning and increase flour yield. The progress of wheat conditioning in preparing wheat for milling is also discussed, along with current trends in grinding the wheat kernel. These advancements collectively contribute to enhancing flour quality, production efficiency, and overall milling performance.

PL

Sposób przemiału ziarna pszenicy ewoluował na przestrzeni ostatnich lat, poprzez wykorzystanie nowych technik, pozwalających na uzyskanie mąki o zmiennym składzie granulometrycznym i różnych zastosowaniach. W niniejszej pracy omówiono najnowsze trendy związane z produkcją mąki pszennej, analizując wpływ różnych metod i technologii na jej jakość. Omówiono także wartość przemiałową ziarna, pod kątem otrzymywania mąki o wysokim wyciągu i pożądanych właściwościach wypiekowych. Skupiono się również na innowacjach w procesie oczyszczania pszenicy, omawiając maszyny do sortowania ziarna względem barwy oraz urządzenia do obłuskiwania. Przeanalizowano także postęp w procesie kondycjonowania i rozdrabniania ziarna pszenicy. Wszystkie omówione innowacje przyczyniają się do poprawy jakości mąki oraz efektywności i wydajności produkcji mąki.

3

Dynamic Processes of Substructural Rearrangement under Friction of Carbon Steel

Shevelya Valeriy, Pashechko Mykhaylo, Kalda Galyna, Sokolan Yulia

Advances in Science and Technology. Research Journal

|

2023

|

Vol. 17, no 3

236--248

EN

The effect of heat treatment (tempering temperature after quenching) of medium carbon steels (steel 45 and steel 50) on tribological indicators at sliding friction without lubrication in connection with the change in strength and rheological elastic properties of steel, controlling the dissipative properties of the frictional contact has been studied. Tribotechnical tests were conducted according to two schemes. A high-temperature tribometer was used for “soft” friction according to the “ball-plane” scheme, which allowed varying the temperature of the friction contact. Influence of load-rate modes was studied in more “hard” conditions on the friction machine under the “finger-disk” scheme. Substructural transformations of steel caused by heat treatment were evaluated by changes in amplitude-dependent internal friction on a torsion pendulum-type machine, which also allowed measuring frictional damping (contact internal friction) in the preliminary displacement mode. The interrelation between hardness, elastic modulus and internal friction of steel and wear resistance, wear capacity, friction coefficient and the level of frictional damping has been established. It is shown that the growth of elastic modulus and increase of steel relaxation resistance after the appropriate heat treatment are conjugated with the development of adhesion and setting, which, as topochemical reactions in the solid phase, are the leading forms of contact stress relaxation under the above conditions. Correlation of tribological indicators of external friction with amplitude-dependent and relaxation (temperature-dependent) internal friction taking into account structural state of steel and friction temperature regime is established. Substructural preconditions, dynamic relaxation mechanisms of hardening and load-temperature friction conditions under which martensitic structures exhibit abnormally high wear resistance and significant growth of frictional damping level are considered. The tribological analogue of the Porteuen - Le Chatelier effect, manifesting in the form of frictional self-oscillations in the range of temperatures of dynamic deformation aging is established. A treatment of the nature of the Kael-Ziebel effect, the temperature-rate and load localization of which in friction is associated with the temperature range of dynamic strain aging with Snook-Kester relaxation superimposed, is proposed.

4

Evaluation of the impact of electron beam welding parameters on the mechanical properties and microstructure of the resulting joint for 39CrMoV13 and M50NiL steel grades

Wencel Zbigniew, Wiewiórowska Sylwia, Wieczorek Paweł, Michalczyk Jacek, Gontarz Andrzej

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 4

art. no. e200, 2022

EN

The paper covers a study consisting on the implementation of the electron beam welding process of two steel grades: 39CrMoV13 and M50NiL. The welding process was carried out for two values of electron beam debunching, obtaining a joint having different widths. Then, for the samples, after each welding variant, heat treatment was carried out consisting of double tempering at 520 °C for 3 h, and single freezing at − 84 °C for 3 h, combined with single tempering at 520 °C for 3 h. The impact of the parameters of the electron beam welding process and the subsequent heat treatment process on the mechanical properties and microstructure of the resulting joint was analysed. The conducted tests allowed to select the optimum welding technology combined with the heat treatment process for the tested steel grades ensuring that a weld is obtained in which the level of mechanical properties was close to the level of values obtained for the base material.

5

Studies on the Mechanical Properties of C45 Steel with Martensitic Structure after a High Tempering Process

Woźniak Waldemar, Sąsiadek Michał, Jachowicz Tomasz, Edl Milan, Zając Paweł

Advances in Science and Technology. Research Journal

|

2022

|

Vol. 16, no 3

306--315

EN

This article describes the studies of the mechanical properties of the martensitic structure of C45 steel, obtained as a result of heat treatment. This steel was subjected to high tempering, within the temperature range of 500 ÷ 700°C (every 50°C) and for various exposure times, from 15 minutes to 23 hours. Moreover, martensitic steel was subjected to tests by quenching at a temperature of 850°C for 20 minutes and then tempering it for 1 hour, within the temperature range of 50 ÷ 800°C (every 50°C). The resulting steel samples were subjected to strength tests, that is, to tensile and hardness tests and also to tests on the micro-structure. The results of these studies are presented and discussed, in detail, in terms of their practical application.

6

Szyny o mikrostrukturze bainitycznej

Szymański Michał

Problemy Kolejnictwa

|

2021

|

Z. 193

53--57

PL

W artykule będącym przeglądem literatury opisano bainit jako przykład mikrostruktury stali, która z powodzeniem może być stosowana do produkcji szyn kolejowych. Porównano kluczowe parametry, jakie muszą spełniać szyny kolejowe: odporność na zużycie ścierne, odporność na złuszczanie, obecność białej warstwy dla stali bainitycznej i perlitycznej. Opisano istotną rolę austenitu szczątkowego i procesu odpuszczania w kształtowaniu właściwości mechanicznych szyn o mikrostrukturze baintycznej.

7

Rails with Bainitic Microstructure

Szymański Michał

Problemy Kolejnictwa

|

2021

|

Z. 193

115--119

EN

The review article describes bainite as an example of a steel microstructure that can be successfully used in the production of railway rails. A comparison has been made between the key parameters to be met by railway rails: resistance to abrasive wear, resistance to flaking and presence of white etching layer for bainitic and pearlitic steel. The important role of residual austenite and the tempering process in shaping the mechanical properties of rails with bainitic microstructure has been discussed.

8

The effect of heat treatment on mechanical properties of 42CrMo4 steel

Çalık A., Dokuzlar O., Uçar N.

Journal of Achievements in Materials and Manufacturing Engineering

|

2020

|

Vol. 98, nr 1

5--10

EN

Purpose: In this study, the effect of heat treatment on the microstructure and mechanical properties of 42CrMo4 steel were investigated. Design/methodology/approach: The samples were annealed at 860°C for 120 min. followed by oil quenching and then tempered at temperatures between 480 and 570°C for 120 min. The microstructure of untreated 42CrMo4 steel mainly consists of pearlite and ferrite whereas the microstructure was found to be as a martensitic structure with a quenching process. Findings: The results showed that there is an increase in yield stress, ultimate tensile stress, hardness and impact energy, while elongation decreases at the end of the quenching process. Conversely, yield stress, ultimate tensile stress and hardness decrease slightly with the increasing of tempering temperature, while elongation and impact energy increase. Research limitations/implications: Other types of steels can be heat treated in a wider temperature range and the results can be compared. Practical implications: It is a highly effective method for improving the mechanical properties of heat treatment materials. Originality/value: A relationship between the mechanical properties and the microstructure of materials can be developed. The heat treatment is an effective method for this process.

9

Deep Cryogenic Treatment and Tempering at Different Temperatures of HS6-5-2 High Speed Steel

Ciski A.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 2

929--934

EN

The paper presents properties of HS6-5-2 high speed steel subjected to deep cryogenic treatment (DCT) and subsequent tempering at different temperatures. DCT process of HS6-5-2 steel leads to shifting of maximum hardness peak to the lower temperature and the reduction of the obtained maximum hardness by about 1 HRC. These changes in hardness may be due to the shifting of the stage of nucleation and growth of carbide phases to lower temperatures or the changes taking place in the matrix, connected with the additional transformation of the martensite proceeding during the isothermal martensitic transformation occurring at cryogenic temperatures and more extensively occurring precipitation processes, lowering the content of the carbon in the martensite, determining thereby its lower hardness.

10

Wpływ obróbki cieplnej na własności i strukturę stali 4330V

Żuk M.

Przegląd Spawalnictwa

|

2017

|

R. 89, nr 5

101--104

PL

W artykule opisano wpływ obróbki cieplnej polegającej na wygrzewaniu stali w zakresie temperatur 100÷900°C na strukturę i własności stali ulepszonej cieplnie 4330V. Celem pracy było zbadanie zachowania się stali przy długim wygrzewaniu bez atmosfery ochronnej w piecu oporowym. Jest to ważny aspekt podczas wykorzystania tego typu stali, gdy są one dostarczane do odbiorcy w stanie gotowym po hartowaniu i odpuszczaniu. Dzięki temu można stwierdzić, do jakich temperatur możliwe jest podgrzanie stali 4330V w procesach łączenia takich jak spawanie. Po przeprowadzonym procesie wygrzewania badanie próbki zostały przebadane pod kątem zmian strukturalnych, twardości i udarności. Przeprowadzane badania wykazały zmniejszenie własności po przekroczeniu temperatury 600°C podczas wygrzewania. Uzyskano znaczny spadek twardości do poziomu 275 HV. W wyniku wygrzewania w temperaturze ponad 800°C nastąpiło zahartowanie materiału w powietrzu.

EN

The article describes the effect of heat treatment of steel in the temperature range of 100÷900°C on the structure and properties of tempered 4330V steel. The aim of the study was to investigate the behavior of steel under long heating without a protective atmosphere in the resistance furnace. This is an important aspect when you use this type of steel, when they are delivered to the customer in the running order after hardening and tempering. This allows you to determine what temperature it is possible to heat the steel 4330V in processes such as welding. After the process of heating test samples were tested for structural change, hardness and toughness. Carried out studies have shown a reduction in properties when temperature exceeds 600°C during heat treatment. A significant drop in hardness to 275 HV was achieved. As a result of heating at a temperature of more than 800°C there has been a hardening of the material in the air.

11

Analiza i opracowanie efektywnego sposobu wstępnego nagrzewania narzędzi do kucia na gorąco

Widomski P., Skwarski M., Rychlik M.

Interdisciplinary Journal of Engineering Sciences

|

2017

|

Vol. 5, no. 1

27--32

PL

Artykuł obejmuje przegląd i ocenę dostępnych metod wstępnego nagrzewania narzędzi kuźniczych. Następnie zawiera kompleksową analizę zmian temperatury, jakie zachodzą na powierzchni i bezpośrednio pod powierzchnią matryc kuźniczych podczas wstępnego ich nagrzewania. Dla wybranej metody grzania wstępnego materiałem wsadowym opracowano szczegółowe wytyczne dotyczące sposobu i czasu nagrzewania wkładek matrycowych. Przygotowano również szczegółowe wytyczne grzania narzędzi na dwóch wybranych prasach.

EN

This article contains an overview of available preheating methods which are commonly used in hot forging processes. Then a comprehensive analysis of the temperature changes that occur on the surface and directly below the surface of the forging die was carried out during the preheating process. The temperature measurement was performed with fast thermal camera and a thermocouple inserted inside the tool. The temperature was measured in traditional preheating process, and its value after preheating was about 200ºC, which can be acceptable, however this process was improper, because of possibility of tempering surface layer of forging tool. That’s why new method of preheating tools in contact with heated billets was developed and detailed instructions for time and layout of billets were prepared. The tool temperature was measured also after application of new method presented in this manuscript, and it reached over 200ºC after two preheating cycles. After three cycles of preheating also good results obtained because temperature in surface layer was about 260ºC. In conclusion, method proposed by authors obtained good result, is quite efficient and prevents from tempering of forging tools. Finally, two pre-heating instructions were prepared, for the Massey 2500T press and the Massey 1300T press, which are attached at the end of the manuscript.

12

Effect of Tempering Temperature on the Mechanical Properties of Cast L35HM Steel

Zapała R., Kalandyk B., Wawro P.

Archives of Foundry Engineering

|

2017

|

Vol. 17, iss. 2

151--156

EN

A possibility to control the strength, hardness and ductility of the L35HM low-alloy structural cast steel by the applied tempering temperature is discussed in the paper. Tests were carried out on samples taken from the two randomly selected industrial melts. Heat treatment of the cast samples included quenching at 900°C, cooling in an aqueous solution of polymer, and tempering at 600 and 650°C. The obtained results showed that the difference in the tempering temperature equal to 50°C can cause the difference of 121 MPa in the values of UTS and of 153 MPa in the values of 0.2%YS. For both melts tempered at 600 °C, the average values of UTS and 0.2%YS were equal to 995 MPa and 933 MPa, respectively. The values of EL and RA did not show any significant differences. Attention was drawn to large differences in strength and hardness observed between the melts tempered at 600 and 650°C. Despite differences in the mechanical properties of the examined cast steel, the obtained results were superior to those specified by the standard.

13

Bainitic reaction and microstructure evolution in two normalized and tempered steels designed for service at elevated temperatures

Ławrynowicz Z.

Advances in Materials Science

|

2017

|

Vol. 17, nr 4(54)

22--36

EN

In the present work conventional heat treatment like normalizing (bainitic microstructure) and tempering of the alloys has been performed. The materials used in this study were two steels, one the laboratory prepared experimental low alloy Cr-Mo steel in comparison to typical commercial 10CrMo9-10 steel. The determined carbon concentrations of the residual austenite at the different temperatures of bainite transformation supports the hypothesis that the growth of bainitic ferrite occurs without any diffusion with carbon being partitioned subsequently into the residual austenite. It was found that bainitic reaction has stopped when average carbon concentration of the untransformed austenite is close to the T0 line and supports formation of bainitic ferrite by a shear mechanism, since diffusionless transformation is not possible beyond the T0 curve. Normalized samples were air cooled down to room temperature before tempering at various temperatures in the range of 500-750°C. Samples have been austenitized at 980°C for 0.5 hour air cooled and tempered at 500, 550, 600, 650, 700 and 750°C for 1 hour. After heat treatment, the assessment in the microstructure and phase precipitation was made using the samples prepared for metallographic and transmission electron microscope (TEM) on thin foils analysis. Quantitative X-ray analysis was used to determine the retained austenite content after heat treatment like normalizing and tempering and the total volume fraction of the retained austenite was measured from the integral intensity of the (111)γ and (011)α peaks. The changes observed in the microstructure of the steel tempered at the higher temperature, i.e. 750°C were more advanced than those observed at the temperature of 500°C. Performed microstructural investigations have shown that the degradation of the microstructure of the examined steel was mostly connected with the processes of recovery and polygonization of the matrix, disappearance of lath bainitic microstructure, the growth of the size of M23C6 carbides, and precipitation of the secondary M2C precipitates. The magnitude of these changes depended on the temperature of tempering.

14

Przetapianie laserowe stali mikrostopowej typu HSLA

Górka J., Opiela M., Stano S.

Przegląd Spawalnictwa

|

2016

|

R. 88, nr 12

18--23

PL

W artykule przedstawiono badania dotyczące przetapiania wiązką laserową stali mikrostopowej typu HSLA – 28MnTiNbVB (Rm = 1060 MPa) o grubości 12 mm. Proces przetapiania został przeprowadzony przy zmiennej energii linowej przetapiania w zakresie od 0,6 do 2,6 kJ/cm. Przeprowadzone badania wykazały, że uzyskane przetopienia charakteryzują się poprawnym kształtem, jednak w ich objętości występują pęcherze gazowe, które mogą pojawić się w związku z bardzo dużymi szybkościami chłodzenia, co powoduje utrudnione wydzielania się gazów ze strefy przetopienia. Pęcherze te powstają w wyniku uwięzienia gazów rozpuszczonych w metalu bądź w wyniku odparowania pierwiastków stopowych. Przetopienia mają strukturę martenzytu listwowego o twardości dochodzącej do 600 HV10. Listwy martenzytu są mniejsze, a drobniejsze wydzielenia węglików są gęściej ułożone niż w materiale rodzimym. Uzyskane wyniki badań wskazują, że stal 28MnTiNbVB wykazuje ograniczoną spawalność w warunkach badania.

EN

In this article examinations of laser beam remelting of microalloyed HSLA steel grade – 28MnTiNbVB (Rm = 1600 MPa), 12 mm thick were presented. Remelting process was carried with variable linear energy in range from 0.6 to 2.6 kJ/cm. Carried examinations have shown that remelted zones have correct geometry, but include gas pores that could be caused by very high cooling rates resulting in hindering gas evacuation from remelted zone. This gas pores are caused by trapping gases dissolved in metal or vaporizing alloying elements. Remelted zone is martensitic with lath structure a hardness of up to 600 HV10. Laths are smaller additionally smaller precipitations are more tightly packed compared to parent material. Examination results show that steel 28MnTiNbVB exhibits limited weldability.

15

Modification of Heat Treatment Parameters for Pearlite Steel Intended for Cold Plastic Working

Grygier D.

Journal of Machine Engineering

|

2016

|

Vol. 16, No. 2

44--51

EN

One of the problems widely discussed in the relevant literature is the fatigue cracking of pearlite steel subjected to cold plastic working, as well as of that being currently in operation. Studies presented in the work were aimed at selection of the parameters, and mainly the time, of heat treatment operations of pearlite steel enabling obtaining cold drawn wires characterised with better plastic properties and higher fatigue resistance than the products achieved during standard processes. The idea of modification was based at possibility of obtaining steel of the sorbite, which are a mixture of ferrite and dispersion cementite of high degree of coagulation. The structures obtained with this method, as being globular, should be featured with better plastic properties than the lamellar structures created during standard diffusion transformation of austenite. In addition the discussed change was to enable decreasing the total surface of interphase boundaries at which the highest delaminations of structure were observed, regardless of whether the cause of the change resulted from presence of non-metallic inclusions or pile-up of dislocations.

16

Characterization of Nanometric-Sized Carbides Formed During Tempering of Carbide-Steel Cermets

Matus K., Pawlyta M., Matula G., Gołombek K.

Archives of Metallurgy and Materials

|

2016

|

Vol. 61, iss. 2A

747--752

EN

The aim of this article of this paper is to present issues related to characterization of nanometric-sized carbides, nitrides and/or carbonitrides formed during tempering of carbide-steel cermets. Closer examination of those materials is important because of hardness growth of carbide-steel cermet after tempering. The results obtained during research show that the upswing of hardness is significantly higher than for high-speed steels. Another interesting fact is the displacement of secondary hardness effect observed for this material to a higher tempering temperature range. Determined influence of the atmosphere in the sintering process on precipitations formed during tempering of carbide-steel cermets. So far examination of carbidesteel cermet produced by powder injection moulding was carried out mainly in the scanning electron microscope. A proper description of nanosized particles is both important and difficult as achievements of nanoscience and nanotechnology confirm the significant influence of nanocrystalline particles on material properties even if its mass fraction is undetectable by standard methods. The following research studies have been carried out using transmission electron microscopy, mainly selected area electron diffraction and energy dispersive spectroscopy. The obtained results and computer simulations comparison were made.

17

Influence of tempering on mechanical properties of induction bents below 540°C

Jankejech P., Fabian P., Broncek J., Shalapko Y.

Acta Mechanica et Automatica

|

2016

|

Vol. 10, no. 2

81--86

EN

The article describes basic principles of induction bending and the change of mechanical properties from as received (straight) pipe made from HSLA steel to induction bend. The main purpose of this article is to experiment with tempering temperatures below 540°C. After tempering at 540°C which is the lowest recommended temperature for post bend heat treatment (PBHT) according to CSA specifications (Canadian Standards Association) the induction bend area in many cases does not achieve the minimum required mechanical properties and therefore it is not accepted for usage. In this article mechanical properties such as tensile, toughness, hardness are evaluated. Also the article contains microstructural analyses and comparison of bended and heat treated samples.

18

The effect of the heat treatment on the 7CrMoVTiB10-10 steel's microstructure and its properties

Bolanowski P.

Challenges of Modern Technology

|

2015

|

Vol. 6, no. 2

10--14

EN

According to the European Standard PN-EN 10216-2 two types of the heat treatment could apply to 7CrMoVTiB10-10 – the modern bainitic boiler steel. The 7CrMoVTiB10-10 steel may have different properties, depending on the chosen method of the heat treatment. This paper shows the differences in the microstructure and the properties occuring after two processes: one of them including normalization and tempering, and the other – hardening and tempering.

19

Computer Advisory System in the Domain of Cooper Alloys Manufacturing

Wilk-Kołodziejczyk D., Kluska-Nawarecka S., Rojek G., Regulski K.

Archives of Foundry Engineering

|

2015

|

Vol. 15, iss. 3

77--80

EN

The main scope of the article is the development of a computer system, which should give advices at problem of cooper alloys manufacturing. This problem relates with choosing of an appropriate type of bronze (e.g. the BA 1044 bronze) with possible modification (e.g. calcium carbide modifications: Ca + C or CaC2) and possible heat treatment operations (quenching, tempering) in order to obtain desired mechanical properties of manufactured material described by tensile strength - Rm, yield strength - Rp0.2 and elongation - A5. By construction of the computer system being the goal of presented here work Case-based Reasoning is proposed to be used. Case-based Reasoning is the methodology within Artificial Intelligence techniques, which enables solving new problems basing on experiences that are solutions obtained in the past. Case-based Reasoning also enables incremental learning, because every new experience is retained each time in order to be available for future processes of problem solving. Proposed by the developed system solution can be used by a technologist as a rough solution for cooper alloys manufacturing problem, which requires further tests in order to confirm it correctness.

20

Computer simulation of microstructure of quenched moulding die

Smoljan B., Iljkić D., Tomasic N.

Archives of Materials Science and Engineering

|

2014

|

Vol. 68, nr 2

81--86

EN

Purpose: The research purpose is to upgrade the mathematical modelling and computer simulation of quenching of steel. Design/methodology/approach: The computer simulation of steel hardening is consisted of numerical calculation of transient temperature field in process of cooling, and of numerical calculation of mechanical properties. The hardness has been predicted by the conversion of calculated time of cooling from 800 to 500°C at specimen points to the hardness. The algorithm is completed to solve 3-D situation problems such as the quenching of complex cylinders, cones, spheres, etc. Findings: On the basis of control volume method, the algorithm for prediction of mechanical properties and microstructure distribution in quenched steel specimens with complex geometries has been developed. The established relations were applied in computer simulation of mechanical properties and microstructure distribution of forged steel centrifugal casting pipe mould. The investigated model of steel quenching can be successfully applied in the practice of heat treatment. Research limitations/implications: The investigation was done on carbon and low alloyed steel. The further experimental investigations are needed for final verification of established model. Practical implications: The established algorithms can be used in heat treating practice. Originality/value: Microstructure distribution is estimated based on time relevant for structure transformation, i.e., the cooling time from 800 to 500°C, t8/5.