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1
Content available remote Odporność na korozję powłoki NiCrFeSi obciążonej cieplnie w atmosferze powietrza i w środowisku siarki
Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Kupiec B., Radoń M., Jacek M.
Przegląd Spawalnictwa
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2018
|
R. 90, nr 4
73--75
PL
Praca dotyczy natryskiwanej plazmowo powłoki NiCrFeSi na podłoże ze stali kotłowej (P 250GH). Powłokę obciążano cieplnie w atmosferze powietrza i w środowisku siarki. Obciążenie cieplne wynosiło 2000 cykli. Jeden cykl obejmował: nagrzewanie do temperatury 560 °C i wygrzewanie w tej temperaturze w czasie 3 minut, chłodzenie do temperatury 300 °C, nagrzewanie do 560 °C i wygrzewanie w tej temperaturze w czasie 1,5 minuty oraz chłodzenie do temperatury 150 °C. Efektem obciążeń cieplnych było zmniejszenie grubości powłoki o 39 μm. Stwierdzono, że siarka dyfundowała w warstwę przypowierzchniową. Tworzące się produkty jej reakcji z niklem i chromem sprzyjały wykruszaniu się składników tej warstwy, które następnie ulegały utlenianiu.
EN
The paper deals with a NiCrFeSi coating plasma-sprayed on a boiler steel (P 250GH) substrate. The coating was heat-loaded in atmosphere of air and in sulfur environment. The heat load comprised 2000 cycles, whereas each of the cycles included: heating up to 560 °C and soaking at the temperature for 3 minutes; cooling down to 300 °C and soaking at the temperature for 1.5 minutes; and cooling down to 150 °C. As a result of such thermal cycling, thickness of the coating was reduced by 39 μm. It has been found that sulfur had diffused into the superficial layer. The occurring products of sulfur reacting with chromium and nickel contributed to spalling of components of the layer which subsequently were subject to oxidation.
2
Content available remote Możliwości poprawy odporności na erozję kawitacyjną staliwnych zaworów hydraulicznych
Orłowicz A.W., Mróz M., Radoń M., Kupiec B., Jacek M., Sobolewska P.
Przegląd Spawalnictwa
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2018
|
R. 90, nr 4
56--58
PL
Powierzchnie wewnętrzne gniazd uszczelniająco-odwadniających zaworów hydraulicznych są zwykle odwzorowane przez wkładki wykonane ze stopu miedzi, które są mechanicznie połączone z korpusem zaworu. Wskutek gwałtownych zmian ciśnienia wody, wkładki te mogą ulec poluzowaniu, co powoduje nieszczelność zaworów. W pracy zaproponowano nowe rozwiązanie poprzez zastosowanie powłoki natryskiwanej plazmowo. Przedstawiono wyniki badań odporności na erozję kawitacyjną dotychczas stosowanego materiału wkładki ze stopu CuZn39Pb2Al oraz materiału powłoki wykonanej z proszku WCCoCr 86104. Oceniono strukturę geometryczną powierzchni kraterów kawitacyjnych (parametr Rt). Stwierdzono, że powłoka naniesiona plazmowo charakteryzuje się zdecydowanie wyższą odpornością na erozję kawitacyjną, w porównaniu do dotychczas stosowanego materiału wkładki ze stopu CuZn39Pb2Al.
EN
Inner surfaces of sealing-draining seats in hydraulic valves are usually reproduced by inserts made of a copper alloy joined mechanically with valve housing. As a result of sudden variations in water pressure, they can be subject to loosening which leads to deterioration of valve tightness. In the paper, a new solution is proposed for finishing surfaces of valve seats by application of a plasma-sprayed coating. The solution is validated by results of cavitation erosion resistance test performed for both the CuZn39Pb2Al alloy used earlier for the inserts and the material of coating made of WCCoCr 86104 powder. The resistance assessment was based on geometrical structure of cavitation craters (parameter Rt). It has been found that the plasma-sprayed coating demonstrated a definitely higher resistance to cavitation erosion compared to CuZn39Pb2Al alloy used earlier for valve seat inserts.
3
Content available The Effect of the Heat Flux Density on Microstructure of Surface Remeltings on C355 Alloy Castings
Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Jacek M., Radoń M.
Archives of Foundry Engineering
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2018
|
Vol. 18, iss. 2
35--38
EN
The paper presents results of a study on the effect of the flux density of heat carried away for the remelting area to substrate in the course of surface remelting with concentrated heat stream on values of structural parameters λ1D and λ2D of α(Al) phase dendrites in C355 alloy. The remeltings were made with the use of GTAW method, at arc current intensity I = 200 A and concentrated heat stream scanning speed vs = 200, 400, 600, and 800 mm/min. The used protective gas was argon supplied at rate of 20 l/min. It has been found that the increase of the rate of scanning with concentrated heat stream results in a change of the remelting-substrate separation surface shape consisting in reduction of the remelting width and depth. This increases the value of the flux density of heat transmitted from the remelting area to substrate which in turn acts in favor of reduction of structural parameters λ1D and λ2D characterizing α(Al) phase dendrites in C355 alloy.
4
Content available Morphology and Material Properties of Carbides in High (24%) Chromium Cast Iron
Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Jacek M., Radoń M.
Archives of Foundry Engineering
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2018
|
Vol. 18, iss. 1
77--80
EN
The present paper is a presentation of results of a study on morphology, chemical composition, material properties (HVIT, HIT, EIT), and nanoindentation elastic and plastic work for carbide precipitates in chromium cast iron containing 24% Cr. It has been found that the carbides differ in chemical composition, as well as in morphology and values characterizing their material properties. The carbides containing the most chromium which had the shape of thick and long needles were characterized with highest values of the analyzed material properties.
5
Content available Improvement of Resistance of Cast-iron Heat Exchangers to High-temperature Corrosion
Orłowicz A. W., Tupaj M., Trytek A., Mróz M., Radoń M., Jacek M.
Archives of Foundry Engineering
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2018
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Vol. 18, iss. 3
49--52
EN
The paper discusses the possibility of improving resistance of heat exchangers made of gray cast iron with flake graphite to high-temperature corrosion by providing them with metallic coatings. A metallic coating containing 76.9% Ni, 19.8% Cr, 1.7% Si, 0.9% Fe, and 0.9% Mn was applied by means of the plasma spraying method and subjected to cyclically variable thermal loads in the atmosphere of solid fuels combustion products (oxygen, sulfur, chlorine, and sodium). In a 30-day thermal load test held at temperature 500°C it has been found that thickness of the metallic coating decreased from the initial (240 ± 6) μm to (231 ± 6) μm. The depth to which sulfur, chlorine, and sodium penetrated the coating was about 30 μm. Increased oxygen content occurred along the whole coating depth. In the coating area adjacent to the substrate surface, the content was twice as high compared to this observed in the initial coating material. Although presence of oxygen was found within the whole depth of the coating, i.e. (231 ± 6) μm, no signs of susceptibility of the sprayed metallic layer to separation from substrate of gray cast iron with flake graphite were found.
6
Content available A Possibility to Improve Resistance of Cast-iron Wood Chip Fine Grinder Liners to Abrasive Wear
Orłowicz A. W., Mróz M., Tupaj M., Kupiec B., Jacek M., Radoń M.
Archives of Foundry Engineering
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2018
|
Vol. 18, iss. 4
35--38
EN
The paper deals with the issue of potential for improvement of resistance of wood chip fine grinders to abrasive wear by providing them with WCCoCr coating applied with the use of atmospheric plasma spraying (APS). The study focused on establishing parameters of the technological process of spraying a 250–270 μm thick coating onto surface of ductile cast iron castings used to date as grinder linings. The presented data include results of microstructure examination, chemical composition analysis, HV hardness measurements, and scratch tests for both previous and new variant of linings. The obtained scratch test results indicate that the material of the coating is characterized with definitely lower susceptibility to scratching. The scratch made on coating was 75–84 μm wide and 7.2–8.2 μm deep, while the scratch on cast iron was distinctly wider (200–220 μm) and deeper (8.5–12.8 μm). In case of cast iron, the range of variability in scratch width and depth was definitely larger. This can be explained with large difference in hardness of individual components of microstructure of cast iron and significantly larger plastic deformation of cast iron compared to the coating revealed in the course of indenter motion over surfaces of the two materials. It has been found that application of WCCoCr coating offered better resistance of lining surfaces to scratching which can be considered a rationale for undertaking in-service tests.
7
Content available A Possibility to Improve Resistance of Cast-iron Hydraulic Valves to Cavitation Wear
Orłowicz A. W., Tupaj M., Mróz M., Kupiec B., Jacek M., Radoń M.
Archives of Foundry Engineering
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2018
|
Vol. 18, iss. 4
31--34
EN
A common problem encountered in hydraulic valves is a progressing deterioration of tightness of their water flow cutting-off seats. The seats are provided usually with a copper-alloy insert joined mechanically with cast-iron valve housing. The problem of unreliability of such joints can be solved by providing surface of the seat with a coating, deposited with the use of HVOF method and resistant to abrasive and cavitation wear. The tests were carried out for a sealing-draining seat insert made of CuZn39Pb2Al brass used to date and a specimen taken from the cast-iron valve housing which was the substrate for a plasma-sprayed coating of powder containing 86.1% Cr, 7.2% Ni, and 6.7% C. The coating, 345 ± 15 μm thick, was characterized with good quality of bonding with cast-iron substrate and high compactness of the material. The cavitation wear test on materials used in the study were carried out with the use of Vibra-Cell ultrasonic liquid processor (Sonics) equipped with a piezoelectric probe operating at the frequency of 20 kHz. Based on profilograms taken along a line crossing centers of cavitation craters, measurements of the height parameter Rt, and microscopic observations of surfaces it has been found that the coating plasma-sprayed onto substrate of nodular cast iron demonstrated higher resistance to cavitation compared to copper-alloy inserts used so far in cast-iron hydraulic valves. Cavitation craters on the material used typically for valve seats to date were more distinctly outlined and deeper compared to craters observed on the coating. Larger were also sizes of local tear-outs which resulted in larger difference between the peaks line and the valleys line.
8
Content available Cavitation Erosion of Nodular Cast Iron - Microstructural Effects
Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Jacek M., Radoń M.
Archives of Foundry Engineering
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2017
|
Vol. 17, iss. 4
119--122
EN
The paper deals with susceptibility of nodular cast iron with ferritic-pearlitic matrix on cavitation erosion. Cavitation tests were carried out with the use of a cavitation erosion vibratory apparatus employing a vibration exciter operated at frequency of 20 kHz. The study allowed to determine the sequence of subsequent stages in which microstructure of cast iron in superficial regions is subject to degradation. The first features to be damaged are graphite precipitates. The ferritic matrix of the alloy turned out to be definitely less resistant to cavitation erosion compared to the pearlitic matrix component.
9
Content available remote Uwarunkowania polityczno-obronne Polski w kontekście uczestnictwa wojska polskiego w misjach zagranicznych
Jacek M.
Studia Bezpieczeństwa Narodowego
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2013
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R. 3, Nr 4
201--214
PL
Artykuł przedstawia podstawowe uwarunkowania bezpieczeństwa państwa oraz założenia wynikające z pragmatyki obronnej i udziału polskiego wojska w poszczególnych kontyngentach i misjach zagranicznych. Ukazując rożne rodzaje i znaczenie poszczególnych misji zagranicznych, przedstawiono ich uwarunkowania prawne oraz oceniono koszty i korzyści, jakie z tego płyną. Takie założenie badawcze jest istotne w aspekcie prowadzonych działań mających wpływ na funkcjonowanie złożonego systemu bezpieczeństwa państwa. Jednym z takich czynników jest również możliwość poprawy poziomu wyszkolenia żołnierzy w warunkach wojennych, szkoleniowych i stabilizacyjnych, wysoko oceniana przez współdziałające państwa NATO. Tak prowadzona polityka bezpieczeństwa państwa sprzyja rozwijaniu długofalowych korzyści gospodarczych oraz zacieśnia międzynarodowe więzy w kluczowych sprawach dotyczących interesów narodowych na płaszczyźnie militarnej i gospodarczej.
EN
The article presents the basic conditions of state security and guidelines arising from the national defense concept and Polish military involvement in various contingents and foreign missions. Showing the different types and the importance of each of the foreign missions, the benefits, costs of participation and legal conditions were assessed and analyzed. All those aspects are important in terms of conducted activities having an impact on the functioning of a complex system of national security. One such factor is the improvement in soldier training through participation in peacekeeping and stabilizing missions, reaching professional level highly appreciated by other co-operating NATO countries. Well conducted national security policy leads to long-term economic benefits and strengthens international ties in key areas of national interests at the military and economic levels.
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