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1

Effect of Variable Manganese Content on Microstructure of Al-Cu Alloys

Stąpór S., Górny M., Kawalec M., Gracz B.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 4

1377--1383

EN

The presented access the influence of Mn content (0-0.94 wt.%) on the course of the cooling curves, phase transformation, macrostructure, and microstructure of Al-Cu alloys for three series: initial (Series I), with the addition of an AlTi master (Series II), and modified with AlTi5B1 (Series III). The maximum degree of undercooling ΔT was determined based on the cooling curves. The surface density of the grains (NA ) was determined and associated with the inverse of solidification interval 1/ΔTk . Titanium (contained in the charge materials as well as the modifier) has a significant effect on the grinding of the primary grains in the tested alloys. A DSC thermal analysis allowed for the determination of phase transition temperatures under conditions close to equilibrium. For series II and III, the number of grains decreases above 0.2 wt.% Mn with a simultaneous increase in solidification interval 1/ΔT2 . The presence of Al2 Cu eutectics as well as the Cu-, Fe-, and Mn-containing phases in the examined samples was demonstrated using scanning electron microscopy.

2

Effect of Thermal Treatment of Biomedical Ti-6Al-4V Alloy on Corrosion Resistance in Simulated Physiological Solutions

Ryba J., Kawalec M., Tyrała E., Krawiec H.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 1

39--45

EN

The effect of heat treatment on the corrosion resistance of Ti-6Al-4V alloy was investigated in the artificial saliva solution (MAS). It has been revealed that the thermal annealing treatment temperature favors the cathodic reactions and reduce the protective properties of passive film. The heat treatment causes the enrichment of β phase in vanadium. The lowest corrosion resistance in the artificial saliva revealed the Ti-6Al-4V alloy heated for 2 hours at 950°C. Heterogeneous distribution of vanadium within the β phase decreases the corrosion resistance of the Ti-6Al-4V.

3

The Influence of Wall Thickness and Mould Temperature on Structure and Properties of Thin Wall Ductile Iron Castings

Górny M., Kawalec M., Witek G., Rejek A.

Archives of Foundry Engineering

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2019

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iss. 2

55--59

EN

The excellent property combination of thin wall ductile iron castings (TWDI), including thin wall alloyed cast iron (e.g. austenitic TWDI) has opened new horizons for cast iron to replace steel castings and forgings in many engineering applications with considerable cost benefits. TWDI is considered as a potential material for the preparation of light castings with good mechanical and utility properties, the cost of which is relatively low. In this study, unalloyed and high Ni-alloyed (25% Ni) spheroidal graphite cast iron, with an austenitic metallic matrix were investigated. The research was conducted for thin-walled iron castings with 2, 3 and 5mm wall thickness, using different mould temperature (20°C, and 160°C) to achieve various cooling rates. The metallographic examinations i.e. characteristic of graphite nodules, metallic matrix, and primary grains of austenite dendrites (in high-nickel NTWDI) and mechanical properties were investigated. The study shows that homogeneity of the casting structure of thin-walled castings varies when changing the wall thickness and mould temperature. Finally, mechanical properties of thin-walled ductile iron castings with ferritic-pearlitic and austenitic metallic matrix have been shown.

4

Improvement of implementation of the 5S method using the simplified FMEA method

Kawalec M., Pacana A., Rewilak J.

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2018

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z. 119

139--150

EN

Paper presents a proposal for improvement of implementation concerning one of Lean Manufacturing (LM) tools, in particular 5S method. For that purpose there was applied Failure Mode and Effects Analysis (FMEA) in simplified form. A test analysis concerning implementation of the 5S method in one of Subcarpathian companies was performed by a team consisting of workers involved in that implementation of and external experts. Results of that analysis showed that the biggest difficulties playing role in implementation of the FMEA are the ones associated with laziness of workers and shortage of understanding advisability of 5S implementation. Obtained results are aimed at improving implementation of the 5S method in the company. They might be, however, also helpful in implementation of that method in other enterprises.

5

Development of the 5S method implementation on the grounds of collected experience

Kawalec M., Pacana A., Rewilak J.

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2018

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z. 119

127--137

EN

The paper contains proposals of improvement concerning implementation of the 5S method. For that purpose there were used some selected techniques of manufacturing management: team work as well as the cause and effect Ishikawa diagram. The analysis of a pilot implementation was done in one of companies located in south–east Poland by a team which consisted of workers involved in that implementation and external experts. The results of analysis were used for the improvement of approach to implementation of the 5S method in the company. Presented methodology as well as obtained results can assist in implementation of the method in other companies.

6

Influence of heat treatment on the corrosion resistance of Ti-6Al-4V alloy in artificial saliva

Ryba J., Krawiec H., Kawalec M., Tyrała E.

Ochrona przed Korozją

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2018

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nr 9

255--258

EN

The effect of the heat treatment on the corrosion resistance of Ti-6Al-4V alloy was investigated in the artificial saliva solution (MAS). It has been revealed that the thermal annealing treatment temperature significantly changes the properties of the passive film formed on Ti-6Al-4V alloy and decreases its corrosion resistance in the artificial saliva. Enrichment in vanadium of passive film formed on the specimen after heat treatment Ti-6Al-4V_HT favors the cathodic reactions and reduce the protective properties of passive film.

PL

W pracy badano wpływ obróbki cieplnej na odporność korozyjną stopu Ti-6Al-4V w roztworze sztucznej śliny. Wykazano, że podczas obróbki cieplnej zachodzą zmiany w składzie chemicznym na powierzchni stopu Ti-6Al-4V, co prowadzi do obniżenia jego odporności korozyjnej w roztworze sztucznej śliny. Wzbogacenie powierzchni stopu Ti-6Al-4V_HT w wanad podczas obróbki cieplnej faworyzuje reakcje katodowe i obniża właściwości ochronne warstwy pasywnej.

7

Opracowanie technologii cienkich, stałotlenkowych ogniw paliwowych na podłożu anodowym

Kluczowski R., Świeca A., Kawalec M., Krauz M.

Materiały Ceramiczne

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2018

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T. 70, nr 2

152--160

PL

W publikacji przedstawiono prace dotyczące wykonania stałotlenkowych ogniw paliwowych na podłożu anodowym o wymiarach 100 mm  100 mm oraz 50 mm  50 mm i grubości poniżej 1 mm. Zmniejszenie grubości ogniwa paliwowego ma na celu poprawę jego parametrów elektrycznych, optymalizację przepływu gazów do jak i z anody ogniwa paliwowego oraz dodatkowo obniżenie jednostkowego kosztu materiałowego pojedynczego ogniwa paliwowego. Podłoże anodowe o składzie NiO/8YSZ 66/34 (% mas.) wykonano metodą wtrysku wysokociśnieniowego materiałów ceramicznych (CIM). Dobrano spoiwa i plastyfikatory oraz wykonano masę ceramiczną do formowania metodą wtrysku wysokociśnieniowego podłoży anodowych. Zaprojektowano i wykonano formę do wtrysku wysokociśnieniowego podłoża o żądanej grubości. Zoptymalizowano również proces wstępnego wypalania w celu zwiększenia wytrzymałości mechanicznej, pozwalającej na nanoszenie warstw metodą sitodruku bez uszkodzenia podłoża anodowego. Na tak wykonanych podłożach anodowych wykonano pełne ogniwa paliwowe wg ustalonej konfiguracji opracowanej w CEREL. Na podłoże anodowe metodą sitodruku naniesiono warstwę anodową funkcjonalną o grubości 7 µm wykonaną z mieszaniny proszków tlenku niklu NiO (JT Baker)/8YSZ (TOSOH) 50:50 (% mas.), warstwę elektrolitową 8YSZ (TOSOH) o grubości 5 µm. Po wypaleniu tych warstw w temperaturze 1400 °C naniesiono warstwę barierową Gd0,1Ce0,9O2 (Praxair) o grubości 1,5 µm oraz warstwę katodową La0,6Sr0,4Fe0,8Co0,2O3–δ (Praxair) o grubość 30 µm, które następnie wypalono odpowiednio w temperaturze 1350 °C i 1100 °C. Wytworzono serię kompletnych ogniw paliwowych o grubości 0,55 mm o wymiarach 100 mm  100 mm i 50 mm  50 mm. Przeprowadzono badania elektrochemiczne ogniwa, uzyskując wysokie wartości właściwości elektrycznych OCV = 1,051 V i maksymalną gęstość mocy 0,604 W/cm2 przy obciążeniu prądowym 1 A/cm2.

EN

The publication presents works on the development of anode-supported solid oxide fuel cells (AS-SOFC) with base dimensions of 100 mm  100 mm and 50 mm  50 mm and overall thickness below 1 mm. The reduction of the thickness of the fuel cell aims at improving the electrical parameters, optimizing the gas flow to and from the fuel cell anode and further reducing the unit material cost of a single fuel cell. Anode support with the composition of NiO (JT Baker)/8YSZ (Tosoh) 66/34 (wt. %) were made using high-pressure injection moulding of ceramic materials (CIM). Binders and plasticizers were selected and a ceramic mass was prepared for high-pressure injection moulding of anode supports. A mould required for this operation was designed and made. The pre-sintering process has been optimized to increase the mechanical strength, allowing for direct screen printing without damaging the anode supports. Complete fuel cells on such anode supports were made, according to the established procedure developed in IEn CEREL. Two layers were deposited on sintered anode supports, using screen printing method: (i) an anode functional layer with a thickness of 7 μm made of a mixture of nickel oxide NiO (JT Baker)/8YSZ (TOSOH) 50/50 (wt. %), (ii) an electrolyte layer 8YSZ (TOSOH) with a thickness of 5 μm. After firing these layers at 1400 °C, the Gd0.1Ce0.9O2 (Praxair) barrier layer with a thickness of 1.5 μm and the La0.6Sr0.4Fe0.8Co0.2O3–δ (Praxair) cathode layer with thickness of 30 μm were deposited, and subsequently sintered at 1350 °C and 1100 °C, respectively. A series of complete fuel cells with a thickness of 0.55 mm and dimensions of both 100 mm  100 mm and 50 mm  50 mm were manufactured and subsequently tested, achieving high electrical parameters of OCV = 1.051 V and a maximum power density of 0.604 W/cm2 at a current load of 1 A/cm2.

8

Wykorzystanie metod prognostycznych w logistyce

Dziurny A., Kawalec M.

Zeszyty Naukowe Akademii Sztuki Wojennej

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2017

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nr 2(107)

59--77

PL

Każde przedsiębiorstwo wymaga nieustannych przemyślanych zmian, które w razie konieczności dostosują je do zmieniającej się rzeczywistości. W dobie silnej konkurencji i niepewności sytuacji rynkowej priorytetową rolę w logistyce odgrywają prognozy. Są one odpowiedzialne za szereg działań, takich jak wyprodukowanie, dostarczenie, a w dalszej kolejności sprzedanie właściwej ilości produktów lub usług, na jakie w danym czasie występuje przewidywany popyt (zainteresowanie). Prognozowanie jest narzędziem bardzo korzystnym, bowiem ułatwia osiągnięcie równowagi rynkowej. Dlatego też celem niniejszego artykułu jest ukazanie możliwości, jakie daje wykorzystanie metod prognostycznych w tej interdyscyplinarnej dziedzinie nauki.

EN

Every establishment requires continuous, deliberate changes in order to adapt it to the changing reality. In an era of intense competition and market uncertainty, forecasting plays the priority role in logistics. It is responsible for numerous activities such as manufacturing, delivery, and, subsequently, selling the right amount of product or services. It is a very beneficial tool because it seeks to balance the market. This publication tries to define the possibilities offered by the use of forecasting methods in the interdisciplinarity field of science. Therefore, the aim of this article is to point out the possibilities offered by the use of forecasting methods in the interdisciplinary field of science.

9

Polihydroksyalkaniany – zastosowanie i recykling

Kurcok P., Kawalec M., Sobota M., Michalak M., Kwiecień M., Jurczyk S.

Polimery

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2017

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T. 62, nr 5

364--370

PL

Problem wszechobecnych odpadów z niebiodegradowalnych tworzyw polimerowych generuje konieczność poszukiwania materiałów alternatywnych, utylizowanych po użyciu na drodze biodegradacji w wyniku kompostowania. Takimi tworzywami są biotworzywa zawierające polihydroksyalkaniany – biodegradowalne biopoliestry – otrzymywane metodą fermentacji substratów pochodzących ze źródeł odnawialnych. Mogą one stanowić cenny surowiec do wytwarzania substancji pochodzenia naturalnego lub oligomerycznych produktów o zróżnicowanej strukturze łańcucha i różnych grupach końcowych, przydatnych np. jako nośniki leków.

EN

The rising amount of plastic waste derived from non-biodegradable polymeric materials generate the need to find alternative materials which could be biodegraded via composting. One of possible solutions are polyhydroxyalkanoates, biodegradable polyesters obtained by fermentation from renewable resources. They can also serve as valuable raw material for the production of bio-based chemicals as well as oligomeric products with different chain structure and end groups applicable as drug carriers.

10

Rynek samochodów elektrycznych i ich wpływ na funkcjonowanie systemu elektroenergetycznego

Kawalec M., Kapusta B.

Elektroenergetyka : współczesność i rozwój

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2017

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Nr 1(16)

44--49

PL

Artykuł stanowi przegląd dostępnych informacji i opublikowanych raportów dotyczących rozwoju rynku samochodów elektrycznych oraz aktualnych i potencjalnych korzyści płynących z integracji samochodów elektrycznych z systemem elektroenergetycznym. Zaprezentowano sprzedaż i udział samochodów elektrycznych na poszczególnych rynkach w ujęciu historycznym i geograficznym. Pokazano aktualny stan dostępnej infrastruktury do ładowania z podziałem na jej poszczególne rodzaje i ze wskazaniem danych dotyczących jej występowania w poszczególnych krajach. Wyszczególniono mechanizmy służące rozwojowi sieci punktów do ładowania. Zaprezentowano postęp związany z obniżeniem kosztu produkcji i zwiększeniem gęstości energii w bateriach. Wskazano aspekty środowiskowe związane z rozwojem segmentu samochodów elektrycznych wraz z ich wpływem na redukcję CO2 i dywersyfikację źródeł energii. Przedstawiono wyniki analiz dotyczących zaspokojenia zapotrzebowania na energię rozwijającej się floty samochodów elektrycznych i jej wpływu na obciążenie systemu elektroenergetycznego. Uwzględniono również możliwości wykorzystania floty samochodów elektrycznych do świadczenia usług systemowych.

EN

This article constitutes a review of available information and published reports concerning the development of the electric car market as well as current and potential benefits arising from the integration of electric cars with the power system. The sale and share of electric cars on particular markets has been presented from the historical and geographical point of view. The current state of available charging infrastructure, divided into particular types and indicating data concerning its presence in particular countries, has been portrayed. Mechanisms aimed at developing a network of charging facilities have been specified. Progress related to the reduction of production costs and increasing power density in batteries has been presented. Environmental aspects related to the development of electric car segment, along with the impact on reducing CO2 emissions and diversifying energy sources, have been indicated. Results of analyses concerning the energy needed to satisfy the demand of the fleet of electric cars and the impact thereof on the power system load have been reported. Possibilities of using the fleet of electric cars to provide ancillary services have also been taken into account.

11

Możliwości rozwoju silników turbinowych z detonacyjną komorą spalania

Wolański P., Kalina P., Balicki W., Rowiński A., Perkowski W., Kawalec M., Łukasik B.

Prace Instytutu Lotnictwa

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2016

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Nr 3 (244)

202--214

PL

W artykule zaprezentowano obszerne badania zastosowania wirującej detonacji w silniku turbinowym. Stanowisko badawcze umożliwiało dostarczenie powietrza o wydatku 2,5 kg/s i ciśnieniu 2,5 bara z możliwością jego podgrzewania do ponad 100°C. Wykonano układ zasilania stanowiska paliwem podgrzewanym do 170°C oraz dodatkowo gazowym wodorem. Stanowisko badawcze wyposażone było w układy pomiarowe i sterowania: wydatkiem powietrza i paliwa oraz w system akwizycji danych w tym szybkozmiennych przebiegów cisnień w komorze spalania. Szeroko zakrojone badania wirującej detonacji realizowane były na otwartych i zdławionych komorach spalania oraz po dołączeniu ich do turbowałowego silnika GTD-350. Przedstawiono warunki uzyskania stabilnej detonacji. Stwierdzono, że w przypadku wirującej detonacji w silniku zasilanym gazowym wodorem sprawność cieplna może być podwyższona o 5-7 % w porównaniu do sprawności silnika z deflagracyjną komorą spalania.

EN

Extensive and complex studies of the application of continuously rotating detonation (CRD) to gas turbine are presented. Special installation of high pressure preheated air supply system was constructed which allows to supply air at rate of a few kg/s, preheated to more than 100°C and at initial pressure up to 2,5 bar. Supply system for Jet-A fuel which could be preheated to 170°C was also constructed. Additionally gaseous hydrogen supply system was added to the installation. Also measuring system for controlling air flow and measurements of detonation parameters was installed and data acquisition and control system implemented. Extensive research of conditions in which CRD could be established and supported in open flow detonation chambers, throttled chambers and finally in detonation chambers attached to the GTD-350 gas turbine engine where conducted. Condition for which stable detonation was achieved are presented. It was found that for conditions when the GTD-350 engine was supplied by gaseous hydrogen, thermal efficiency of the engine could be improved even by 5-7% as compare to the efficiency of the base engine.

12

Assessment of the airframe systems affecting safety risks caused by large aircraft

Balicki W., Głowacki P., Kawalec M.

Journal of KONES

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2016

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Vol. 23, No. 1

39--46

EN

Hazard is a safety condition that could cause or be a part of unsafe aircraft operation. It also has an impact on aviation safety related to aircraft systems as well as services. Safety risk is a part of so-called safety management and is the predicted probability and severity of the outcomes of a hazard. Aircraft utilized by airlines and cargo operators which have MTOM >5700 kg are defined by authors as a large aircraft and have to be treated in their systems reliability analysis separately from small aircraft. Despite the fact that both types of aircraft categories events are included in the same databases - European Coordination Centre for Aviation Incident Reporting Systems (ECCAIRS) and Aircraft Continuing Airworthiness Monitoring (ACAM), due to different predominant systems failures could not be considered in the same way. The authors have performed processing of the data contained in available databases analysing large aircraft airframe systems faults, which were assigned to the specific ATA chapters. The most frequently occurring defects of the aircraft systems were identified. The goal of this article is to present a method of the current reliability of large aircraft systems assessment. Based on it, the authors are proposing a way of safety risk estimation and prediction of the safety levels for the next two years. The results of this analysis may support the decisions of supervisory authorities in the areas where security threats are most important. They can also help aircraft operators with identification of the aircraft systems, which require special attention.

13

Effect of Titanium and Boron on the Stability of Grain Refinement of Al-Cu Alloy

Górny M., Sikora G., Kawalec M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 3

35--38

EN

The present research was conducted on thin-walled castings with 5 mm wall thicknesses. This study addresses the effect of the influence of different master alloys, namely: (1) Al-5%Ti-1%B, (2) Al-5%Ti and (3) Al-3%B, respectively on the structure and the degree of undercooling (ΔTα = Tα-Tmin, where Tα - the equilibrium solidification temperature, Tmin - the minimum temperature at the beginning of α(Al) solidification) of an Al-Cu alloy. The process of fading has been investigated at different times spent on the refinement treatment ie. from 3, 20, 45 and 90 minutes respectively, from the dissolution of master alloys. A thermal analysis was performed (using a type-S thermocouple) to determine cooling curves. The degree of undercooling and recalescence were determined from cooling and solidification curves, whereas macrostructure characteristics were conducted based on a metallographic examination. The fading effect of the refinement of the primary structure is accompanied by a significant change in the number (dimension) of primary grains, which is strongly correlated to solidification parameters, determined by thermal analysis. In addition to that, the analysis of grain refinement stability has been shown with relation to different grain refinements and initial titanium concentration in Al-Cu base alloy. Finally, it has been shown that the refinement process of the primary structure is unstable and requires strict metallurgical control.

14

The influence of the shape of the combustion chamber on exhaust gases toxicity in T370 engine

Kalina P., Kawalec M.

Journal of KONES

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2015

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Vol. 22, No. 2

104--108

EN

An important issue in construction of combustion chamber in compression-ignition engines is proper selection of its shape and size. Both features are dependent on several factors such as fuel injector location and angle, spray atomizer selection (amount of holes, their diameter and angular position), location of inlet valve and air turbulence. By doing research on prototype engine T370, an analysis of influence of combustion chamber size and its modifications going towards lip construction on flue gas toxicity was done. The diameter and depth of combustion chamber was being changed while maintaining the same compression ratio. After that, a modification of tested combustion chambers was made by creating so called “lip”, which aim was to create a swirl of injected fuel in the vertical plane. To visualize the changes in swirl, a numerical analysis of fuel injection into combustion chamber was made. In discussed study, emission tests were performed according to ECE-R49. During the research six combustion chambers with diameters 60, 63 and 66 mm (and their modification) were investigated. Tests were performed for several types of injectors and different injection timing. However, for analysis of combustion chamber size the results are presented for the same injectors but with optimized injection timing.

15

Aircraft fuel consumption and emissions during cruise, effect of the jet stream

Głowacki P., Kawalec M.

Journal of KONES

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2015

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Vol. 22, No. 2

63--70

EN

Article presents the results of fuel consumption calculation during cruise compared to remaining aircraft flight phases. Based on fuel consumption, methodology of pollutants quantitative estimation emitted by turbine engines has been developed. Material provides evaluation results of aircraft CO2, CO and NOx effusion using fuel consumption data taken from aircraft Flight Data Recorder (FDR) during cruise of various aircraft types. Knowledge of the amount of aircraft emissions on high altitudes is very important for climatologists in order to understand eventual changes in the Earth atmosphere due to aviation activities. The authors would like to draw attention of the aviation professionals to the fact that aircraft fuel consumption during cruise; thereby amount of toxic content in the exhaust from the turbine engine is significantly higher especially during flights against jet stream. Thousands flights of two operators were processed using algorithms developed by authors. The article gives an example of fuel consumption and thereby CO2, CO and NOx emission estimation based on engine performance taken from their test cell results. Calculations were performed with the consideration of the factor for engines deterioration through operation time provided by its manufacturer.

16

Aircraft emissions during various flight phases

Głowacki P., Kawalec M.

Combustion Engines

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2015

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R. 54, nr 3

229--240

EN

Article presents methodology of pollutants quantitative estimation emitted by turbine engines. Provides calculation results of aircraft CO2, CO and NOx effusion using fuel consumption data taken from aircraft Flight Data Recorder (FDR) in the so–called landing and takeoff cycle (LTO) and during remaining flight phases (climb from 3000 feet to cruise altitude, cruise, descent to 3000 feet) of various aircraft types. The authors would like to draw attention of the aviation professionals to the fact that amount of toxic content in the exhaust from the turbine engine is significant especially during cruise, but turbine engine emission standards are applied only to LTO cycle defined in the ICAO Annex 16 vol.2. The article gives an example of CO and NOx emission estimation based on engine performance taken from ICAO Engine Emission Data Bank. Such engine authors named “ideal”. Calculations were done using actual values of aircraft fuel consumption and duration of the airplane maneuvers for each flight.

PL

Artykuł opisuje metodologię ilościowego oszacowania emisji toksycznych składników spalin przez lotnicze silniki turbinowe. Prezentuje wyniki obliczeń emisji CO2, CO i NOx na podstawie danych z pokładowego rejestratora parametrów lotu samolotu. Kalkulacji dokonano dla cyklu startu i lądowania i pozostałych faz lotu (wznoszenie z 3000 stóp do wysokości przelotowej, przelot, schodzenie do wysokości 3000 stóp) samolotów różnych typów. Autorzy pragną zwrócić uwagę ekspertom zajmującym się lotnictwem na fakt, że ilość toksycznych składników spalin emitowanych przez silniki odrzutowe jest szczególnie duża w trakcie przelotu, a normy obowiązują dla cyklu startu i lądowania zdefiniowanego w aneksie 16 t.2 ICAO.W artykule podano przykłady oszacowania emisji CO i NOx posługując się charakterystykami silników opracowanym i na podstawie danych zawartych w bazie danych ICAO. Silniki te nazwano „idealnymi”. Obliczeń dokonano posługując się bieżącymi danymi zużycia paliwa i czasu manewrów samolotów dla każdego lotu.

17

Corrosion Resistance of High-Alloyed White Cast Iron

Kawalec M., Krawiec H.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 1

301--303

EN

The paper presents the results of corrosion resistance tests carried out on high-alloyed white cast iron. Tests were performed in 0.1 M NaCl by the technique of linear voltammetry. The test material was collected from six high-vanadium cast iron melts with a variable content of carbon and vanadium, and thus with different microstructure. Studies have confirmed that the type of crystallised microstructure has a very important effect on the alloy corrosion resistance. The highest corrosion resistance showed the alloy with a ferritic matrix containing the spheroidal precipitates of vanadium carbide VC, while the lowest had the eutectic alloy with a pearlitic matrix.

PL

W pracy przedstawiono wyniki badań odporności na korozję wysokostopowego żeliwa białego. Badania przeprowadzono w 0,1M roztworze NaCl techniką woltamperometrii liniowej. Materiał do badań pobrano z sześciu wytopów żeliwa wysoko-wanadowego o zmiennej zawartości węgla i wanadu, a tym samym o różnej mikrostrukturze. Badania potwierdziły, że rodzaj wykrystalizowanej mikrostruktury ma bardzo istotny wpływ na odporność na korozję stopu. Najwyższą odporność na korozję wykazał stop o osnowie ferrytycznej ze sferoidalnymi wydzieleniami węglików VC, natomiast najniższą - eutektyczny stop o osnowie perlitycznej.

18

Influence of Structure on the Thermophisical Properties of Thin Walled Castings

Górny M., Lelito J., Kawalec M., Sikora G.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 2 spec.

23--26

EN

This study addresses the effect of the cooling rate and of titanium additions on the thermophysical parameters of thin-walled compacted graphite iron (TWCGI) castings. Various molding materials were used (silica sand and insulating sand LDASC- Low-Density Alumina-Silicate Ceramic) to achieve different cooling rates. Different titanium additions were caused by various amount of Ferro Titanium. The research work was conducted for thin-walled iron castings with a 3-mm wall thickness. The tested material represents the occurrence of graphite in the shape of flakes (C and D types, according to the ISO Standard), nodules or compacted graphite with a percent of nodularity and different shape factor. Thermal conductivity has been determined by the laser flash technique in a temperature range of 22-600°C. The results show that the cooling rates together with the titanium content largely influence the graphite morphology and finally thermal conductivity of thin walled iron castings.

19

Anisotropic in Situ Metal Matrix Composite Reinforced with VC Carbide Fibres

Kawalec M., Górny M., Sikora G.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 1

21--24

EN

A eutectic reaction is a basic liquid-solid transformation, which can be used in the fabrication of high-strength in situ composites. In this study an attempt was made to ensure directional solidification of Fe-C-V alloy with hypereutectic microstructure. In this alloy, the crystallisation of regular fibrous eutectic and primary carbides with the shape of non-faceted dendrites takes place. According to the data given in technical literature, this type of eutectic is suitable for the fabrication of in-situ composites, owing to the fact that a flat solidification front is formed accompanied by the presence of two phases, where one of the phases can crystallise in the form of elongated fibres. In the present study an attempt was also made to produce directionally solidifying vanadium eutectic using an apparatus with a very high temperature gradient amounting to 380 W/cm at a rate of 3 mm/h. Alloy microstructure was examined in both the initial state and after directional solidification. It was demonstrated that the resulting microstructure is of a non-homogeneous character, and the process of directional solidification leads to an oriented arrangement of both the eutectic fibres and primary carbides.

20

Zintegrowany silnik rakietowo-strumieniowy

Wolański P., Kalina P., Kawalec M.

Prace Instytutu Lotnictwa

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2014

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Nr 1 (234) March 2014

104--108

PL

W artykule przedstawiono unikatową koncepcję budowy zintegrowanego silnika rakietowostrumieniowego. Proponowany system napędowy łączy różne tryby pracy tj.: rakietowy, rakietowo-strumieniowy, strumieniowy. Odpowiedni tryb pracy jest włączany w zależności od warunków lotu i realizowanej misji w celu optymalnego wykorzystania zalet poszczególnych układów wytwarzających siłę ciągu. Silnik rakietowy służy do przyspieszenia obiektu do prędkości okołodźwiekowej. Dla zakresu prędkości 1-2 Ma napęd przechodzi w tryb rakietowo-strumieniowy. Następnie układ napędowy przechodzi stopniowo na napęd strumieniowy. Silnik wyposażono w pierścieniową komorę spalania wykorzystującą efekt wirującej detonacji. Silnik taki ma prostą i zwartą konstrukcję dzięki wyeliminowaniu ciężkiego i skomplikowanego zespołu silnika turbinowego.

EN

The article presents a unique concept for the construction of integrated rocket-ramjet engine. The proposed power system combines following operation modes of engine: rocket, rocket-ramjet and ramjet. The appropriate mode of operation is activated depending on flight conditions and undertaken mission in order to optimal utilization of advantages of particular thrust generating systems. Rocket engine is used to accelerate an object to the circum-sound speed. For object speed in range of 1 to 2 Ma the drive changes mode of operation to rocket-ramjet one. Then the driving system gradually undergoes to ramjet mode. Engine is equipped with toroidal combustion chamber which uses effect of rotating detonation. Thanks to elimination of heavy and complex turbine engine assembly the presented engine is distinguished by simple and compact structure.