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1

Test of the suitability of chosen materials in terms of their use for removing oil spillage from the water environment

Guźlińska E., Kończewicz W., Otremba Z., Trojnar D.

Journal of KONES

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2016

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Vol. 23, No. 3

171--176

EN

The paper presents the study about impregnability of various loose materials dedicated as the fillers of oil absorbent socks and booms. Purpose of the survey was finding the material, which is characterized with the smallest hygroscopicity and the highest absorptivity towards typical fuels used in the marine techniques. The cause of take up the topic is the fact, that the contamination of sea areas with petroleum substances are unfortunately very often, are dangerous for natural environment and first of all are so hard to remove from the sea surface. The natural, mineral and synthetic sorbents were studied under laboratory conditions. Samples of the ten kinds of sorbent, each of 2 grams, were treated with the same amount of the diesel fuel, heavy fuel oil and the sea water also, each time in the same period-time (5 minutes). In order to determine the reliability of the results the authors carried out the test fivefold for the one of searched sorbents (recognized as the most hydrophobic-oleophilic substance). The results are presented in graphical form, based on which we are able to select sorbent that fulfils the greatest extent of required expectations. The results of performed tests show that the method that was described in the paper could be used to test the suitability of various materials for the production of devices for collecting the oil film from the surface of the water.

2

Spin test rig : most important stage of tunnel thruster’s overhaul

Stępkowski M., Kończewicz W., Iwanicki L.

Journal of KONES

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2016

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Vol. 23, No. 3

505--510

EN

Tunnel thrusters during overhaul pass through several quality tests. After disassembly any clearance, shrink or subassembly are noticed. Measurements taken at verification stage determined which parts should be replaced. Definitely, the most important of tunnel thruster operation is bearings condition. Despite many years of experience, it is hard to find micro damages in the bearings without special devices. After assembly of tunnel thruster, the final stage is spin test. The spin test rig is equipped with bearings condition monitoring system including vibration, temperature and pressure inside the tunnel thruster live monitoring. During 4 hours of spin test, it is possible to check vibrations on the thruster and if any damage occurs it can be easily found, on which part of bearing appeared. Spin test rig gives possibility to check misalignments, gear condition, temperatures during 4 hours of operation and check oil quality (oil particle content acc. to ISO 4407 and water content). Spin test guarantees proper operation of tunnel thrusters after overhaul. If any damage appears during the spin test it can be easily eliminated. Without the spin test after overhaul, damage will be found after assembly on the vessel – on the sea trials. When damage is found too late, there is an additional cost for company to dock the vessel again and disassembly tunnel thruster for inspection. From economical point of view, the spin test rig gives possibility to avoid extra costs. Every passed spin test gives certificate of proper vibration level and proper assembly of thruster’s elements.

3

Comparison of nonwoven fabrics in terms of usefulness for oil spill combat

Kończewicz W., Otremba Z., Sałek K., Walaszkowska N.

Journal of KONES

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2015

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Vol. 22, No. 3

99--103

EN

The petroleum substances (oil) spilled on the hard surface can be easily neutralized and collected by using powdery or granular sorbents. We are dealing with more difficult situation when oil spill appears on the soft ground or on the surface of the water. Extremely difficult is removing the oil from body of water polluted by dispersed one. In such cases useful are various balls, sleeves and mats filled by nonwovens. It is important to identify a material, which strongly absorbs different type of oil in a wide temperature range. At the same time, such material should have physical properties allowing easy and rapid contact with the spilled oil and then its removal from the environment. This paper provides an overview of impregnability of nonwoven fabrics made from two materials – polypropylene and cotton. The impregnability was tested against the water and the used lubricate oil. The tests were carried out by using experimental device constructed by members of the student’s scientific society at Faculty of Marine Engineering (Gdynia Maritime University). Principle of construction of testing device takes into account aspect of placing the sorbent in the package as well as possibility of repeating the experiment in precisely defined measurement conditions. Among tested materials, the best in terms of oil sorptivity proved to be polypropylene. The same material was the least absorbing water. It can therefore be assumed that this material is the most suitable for removing oil from the polluted water.

4

The prototype project of the position to designate the screw thruster lobe specific gravity

Kończewicz W., Stępkowski M., Skowroński M., Iwanicki L.

Journal of KONES

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2014

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Vol. 21, No. 3

165--170

EN

During the exploitation screw thruster, lobes are being defected in many ways. Sample types of damages are as follow: the material damages caused by cavitation, corrosion, deflection. In order to facilitate and to improve the quality of repairing activities, the idea of make the position to designate screw thruster lobes specific gravity has been initiated by Rolls-Royce Poland Company and Nautica Academic Circle. Incorrect lobes balance influences on irregular work of the screw, which results in the occurrence of adverse effects such as generation of vibration or increasing probability of mechanical elements damages during the exploitation. Screw thruster lobe specific gravity designation helps in identification of areas for treatment (welding, grinding) to achieve the desired parameters. The creation of designate screw thruster lobes specific gravity position gave the possibility of using the innovative scanning in 3D, which shows very clearly the picture of the scanning item. With Scanect and Autodesk Inventor 2014 software, we can manipulate the resulting image. This makes possibility of the lobes gabarits measurement. What is more, it designates the specific gravity exact to 10%.It increases the quality of the lobe renovation and these results in an improvement the screw thruster lobe’s work efficiency.The cooperation of The Maritime University in Gdynia and Rolls-Royce Poland Company resulted in creating the prototype, which will be tested by service technics in working circumstances.

5

Laboratory study of effectiveness of sorbents intended for oil spill combating

Kończewicz W., Walaszkowska N., Lachowicz D., Otremba Z.

Journal of KONES

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2014

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Vol. 21, No. 4

247--254

EN

While various floating objects driven by combustion engines are exploited, unintentional oil spill might be done (caused by fuel, lubricant or gear leaks). So arisen undesirable pollution is usually removed from water environment using various types of booms, pumps and skimmers as well as by various oil-sorption materials. Sometimes oil spills are dispersed into bulk of water (only in water-areas that are rich with oil-consumption bacteria). The reason for undertaking investigations described in this paper was a real problem with oil pollution in narrow spaces of port and shipyard basins, marines and inland shipping routes. The paper describes study on sorptivity of chosen materials proposed as measures to combat oil spills on the water surface. Natural, synthetic and mineral materials were investigated at laboratory conditions, which was based on contacting those materials with, on the one hand, only water and – on the second hand – with oil in two ways, namely: with oil only and with oil as a film on the water surface. The authors presents in graphical form dependencies of sorptivity on a type of sorbent and on the time. In addition, air temperature, oxygen content in the water, density and viscosity oil are registered. The data obtained from the measurements play a role input data to establish procedure for usefulness of defines sorbent-materials in define conditions of application.

6

Study on oil sorbents effectiveness

Kończewicz W., Grabowska O., Lachowicz D., Otremba Z.

Journal of KONES

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2013

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Vol. 20, No. 1

135--138

EN

The paper presents search for objective and quantitative method of determination usefulness of various loose sorbents destined for cleaning surfaces polluted with oil. The motivation to take up the topic is that oil pollution emergence in marine areas remains still as the environmental problem. During the ship exploitation there is possibility of appearing of the fuel oil, lubricating oil, hydraulic oil or even transformer oil leaks on the board which might be erased by washing or using sorbent powders and granules or mates. In the case of disposing the washing liquids, the large volume of oil-in-water emulsion is forming which is gathered in a tank and further transported to the vessel cleaning system. In the case when sorbents are applied in an early phase of oil leakage, the vessel cleaning system is less overloaded which reduce the probability of failure. We report analyses of effectiveness of mineral and organic sorbents. The time-period of incepting of defined amount of oil by define amount of sorbent is applied as the sorption effectiveness parameter. Time plots of oil sorption as well as visualizations of this process are presented. Method to characterize the efficiency of sorbents in relation to used lubricating oil is proposed which will stand as the base for further works directed towards elaborating optimal sorbent-set which can be rapidly used for combat spillages and leaks of oils and even other liquid dangerous payloads carried by ships.

7

Marine gas engine marine gas engines application speaking of 6th Marpol Annex

Wandor J., Kończewicz W., Wojtaszak M., Kamieniecki M.

Journal of KONES

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2013

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Vol. 20, No. 4

479--484

EN

The International Maritime Organization set up a global strategy for reducing emission of sulphur from marine fuels, from 4.5% to 0.5% by the end of the year 2020. In order to such strategy, ship-owners need to fulfil increasing demands according to reduce pollution. New regulations, force ship-owners to reduce production of pollution, but as the devices create to remove some part of pollution are very expensive in use, began to search for cheaper and more effective solutions. The main aim of this article is to present superiority of using gas fuel over liquid fuel on ships. The construction of marine engines, run by a gas fuel is in the scope of interest of scientist’s research during the last couple of years. This branch of technology develops very dynamic recently, according to savings that can be reach while using gas engines on ships. Apart of cost reduction, new types of marine engines are able to cope with more and more restrictive regulations that are published in international convention MARPOL. Such restriction became the reason for the biggest, international corporations, specialists in engines production, to carry on long-term researches on new ways to power ship engines. One of the world’s greatest engine producer is British Rolls-Royce that became pioneer and built the first gas engine. New power unit, Bergen B-gas B35:40V is the one of the most modern type of such engine in the world. The solid construction of this engine was based on engine B32. It became very efficiently because of many rationalizations in maintenance and exploitation. Two main priorities, while developing conception for this model, were minimization of fuel consumption and operating simplification. The authors of these article present advantages of using marine engines powered by gas, according to the international MARPOL regulations that became very restrictive in order to protect marine environment. As the examples were used products of Rolls-Royce Company.

8

Concept of the skimmer specialized for oil removal from the port waters

Kończewicz W., Mazurek M., Otremba Z., Sarad T.

Journal of KONES

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2013

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Vol. 20, No. 2

189--192

EN

Project analysis to meet needs for equipment customized to pumping out surface forms of oil in the port and other narrow basins are reported in this paper. New elements of the technical concept of the skimmer to eliminate the disadvantages of structurally similar devices are proposed - esential componets of the new type of skimmer currently elaborating in the Student Scientific Society „Nautica“ (at Faculty of Marine Engineering of the Gdynia Maritime University) are demostrated. The first motivation to this work is that the consequence of growing usage of ships in the world transport is necessity to search for more fast and efficient methods to remove oil pollutions from the water surface and the second one – preparation of appropriate training and research equipment for the continuous improvement of its construction as well as the manner of its use in variety conditions. Port areas are relatively small and they have numerous hard to navigate places, therefore oils which leaked from ships or transloading equipment are difficult to remove from the water surface. Those all factors promote the development of the new and innovative solutions for more efficient water treatment. New solutions of the technical concept of the skimmer are proposed here - among other the theoretically justifiable triangular inlet openings with the system of vertical positionnig relative to the water surface.

9

Regeneracja zaworów silników okrętowych metodą napawania plazmowego

Smoleńska H., Kończewicz W., Łabanowski J.

Przegląd Spawalnictwa

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2011

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R. 83, nr 9

73-78

PL

W artykule przedstawiono zastosowanie procesu napawania plazmowego (PTA) do regeneracji zużytych przylgni zaworów wylotowych okrętowych silników Diesla. Zużyte zawory, po odpowiedniej selekcji, poddano obróbce skrawaniem w celu nadania odpowiedniego kształtu powierzchni przylgni, a następnie poddano procesowi napawania plazmowego z wykorzystaniem trzech rodzajów proszków na bazie kobaltu. Wybrane proszki charakteryzowały się wysoką zawartością chromu (ok. 30%), niską zawartością niklu (ok. 2%) oraz różnymi zawartościami wolframu (ok. 5-9%). Napawanie zostało przeprowadzone automatycznie za pomocą urządzenia do napawania plazmowego proszkowego EUTRONIC GAP 200 firmy CASTOLlN. Po napawaniu zastosowano obróbkę skrawaniem w celu nadania wymaganej geometrii oraz gładkości powierzchni. Wykonano badania metalograficzne oraz pomiary mikrotwardości na powierzchni przylgni oraz na przekroju poprzecznym prostopadłym do powierzchni napoiny. Wytworzone warstwy wykazują budowę dendrytyczną, składającą się z roztworu stałego (zawierającego głównie kobalt, żelazo i nikiel) oraz eutektyki węglikowej (bogatej w wolfram, chrom i krzem). Warstwy wykonane z proszku o większej zawartości wolframu wykazały większą twardość na przekroju poprzecznym napoiny. Zastosowanie takiej metody regeneracji zaworów może wydłużyć czas ich eksploatacji.

EN

The paper examines the application of plasma transfer arc (PTA) hard-facing to regenerate the exhaust valve face used marine diesel engines. Worn jumper, after appropriate selection, were machined in order to give proper shape of face of wear surface and then PTA hard-facing using three types of cobalt-based powders. Selected powders were characterized by a high content of chromium (30%), a low content of nickel (about 2%) and different contents of tungsten (about 5-9%). Welding was performed automatically using the Castolin EUTRONIC GAP 200. After hard-facing process, machining gives the desired geometry and surface quality. Study was carried out metallographic and microhardness measurements on the face of wear surface and the cross-section perpendicular to the surface of weld metal. A dendritic structure consisting of a solid solution (mainly with cobalt, iron and nickel) and the eutectic carbide (rich in tungsten, chromium and silicon) are observed in the layers. The layers are made of powder with a higher tungsten content show higher hardness on cross-section of weld metal. Using this method of valves regeneration can extend their lifetime.

10

Regeneracja zaworów silników okrętowych metodą napawania laserowego

Smoleńska H., Kończewicz W., Łabanowski J.

Przegląd Spawalnictwa

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2011

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R. 83, nr 9

27-31

PL

Analizowano możliwości zastosowania napawania laserowego proszkiem na bazie kobaltu przylgni zaworu wylotowego okrętowego silnika Diesla. Po przygotowaniu przez obróbkę skrawaniem, wyselekcjonowane zawory poddano napawaniu laserowemu z wykorzystaniem lasera wysokiej mocy ROFIN DL020. Do napawania użyto proszku EuTroLoy 16012. Jeden z zaworów został pocięty i poddany badaniom metalograficznym oraz pomiarom twardości, a pozostałe zawory zostały zainstalowane w silniku okrętowym, w którym pracowały przez ok. 3000 h. Badania przeprowadzone dla stanu wyjściowego wykazały typową strukturę dendrytyczną napoiny, charakterystyczną dla warstw napawanych, z równomiernie rozłożonymi wydzieleniami węglików w obszarach międzydendrytycznych oraz w minimalnym stopniu zmienioną strukturę w podłożu stalowym. Analogiczne badania wykonano dla zaworów po okresie eksploatacji. Przylgnie zaworów wykazywały niewielkie efekty zużycia. W mikrostrukturze napoiny stwierdzono nieznaczne zmiany spowodowane głównie efektami procesów dyfuzyjnych zachodzących w temperaturze pracy oraz spadek twardości. Technika napawania laserowego okazała się bardzo przydatna do regeneracji zaworów silników okrętowych.

EN

We analyzed the applicability of cobalt-based powder laser hard-facing of exhaust valve face of marine diesel engine. After preparation by machining, using of high-power Rofin DL020 laser selected valves were hard-facing. The EuTroLoy 16012 powder were used. One of the valves were cut and subjected to metallographic examinations and hardness measurements, while the other valves were assembled in the engine, which worked for about 3000 h. The tests conducted for the baseline showed a characteristic for surfaced layers dendritic structure of the overlay with carbides uniformly deposited in interdendritic areas and minimally changed the structure of the substrate steel. A similar study conducted for the valves after the operation. Valves face showed a little effects of wear. The microstructure of the deposit was found mostly minor changes due to the effects of diffusion processes occurring in the operating temperature and a decrease of hardness. Laser hard-facing technique has proven very useful for the regeneration of marine engine valves.

11

Study on structures and properties of the laser cladding exhaust valve after service

Kończewicz W., Krużycki P., Smoleńska H.

Journal of KONES

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2010

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Vol. 17, No. 3

211-216

EN

The cobalt base laser cladding layers which were built up on the exhaust valve head face of the heavy loaded marine diesel engine have been investigated. The valve head with cladded face were served successfully for 3000 hours in the engine of the Dar Młodzieży. After removing from the valve head from the cylinder head the face surface were fully inspected. The surface topography and roughness were evaluated. Microstructure on the cross section of the clad layer were analyzed using Scanning Electron Microscope (SEM) equipped with energy dispersive spectroscopy (EDS. Also microhardness of the clad layer was measured. The service conditions resulted with the formation of the scale which had different thickness and tended to cracking and spalling. The microstructure of the clad layers after service did not demonstrated serious degradation process. The decrease of the hardness numbers was observed but still clad layer presented higher hardness than steel base. This type of clad layer underwent intensive laboratory examinations which contained oxidation experiments at different temperatures and corrosion in exhaust gases, long time exposition in laboratory engine and in the end 3000 hours successfully service on the ship. After such experience laser cladding cobalt base layers may be recommended as a useful solutionfor both prolongs of the service life and a method of the regeneration of the slightly used valve heads is suitable for practical applications.

12

Concept of multifunctional small cleanup ship

Otremba Z., Kończewicz W., Czoska P., Krużycki P.

Journal of KONES

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2010

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Vol. 17, No. 3

341-345

EN

The Baltic Sea belongs to a global system of protected area and has a status of Particularly Sensitive Sea Area (PSSA) which results in a mechanism for strict control on International shipping activities within designated areas through the UN International Maritime Organization (IMO). Countries can declare such areas, and then establish rules for their protection. Additionaly almost the entire Polish coastline has been notified to the European Natura 2000 sites. Inside coastal NATURA 2000 areas some places are covered by increased protection because of belonging to a system of coastal and marine Baltic Sea Protected Areas (HELCOM BSPA). On the other hand intensive shiping in the vicinity of the Polish coast, high population density in the coast, tourism as well as coastal and marine industry necessitate special attention in relation to environment protection. Therefore, inter alia, novel techniques for the surveillance of purity of coast and coastal water are desirable. In the case of large spill - existing combating system provides only partly reducing ofamount of oil entering the sea environment. Elimination ofa greatest number of small oil spillages or discharges is possible, if well developed techniques and organization systems is used. The paper presents pre-project assumptions for small multifunctional ship designed for inshore activity — especially for port inspections and service, as well as for removal of floating and submerged rubbish and combating small oil spillages. We have analyzed possibility to achieve expected exploitive features of the ship using present knowledge for construction of small ship hulls applying principles of engine and navigational equipment steeringfor choosing the best route and for optimization the water surface cleaning-works as well as to minimize the energy consumption. We expect, that this ship - owing to main designations thanks to modern technical equipment and sophisticated software -will also fulfill conditions as an educational or as a training vessel.

13

Failure analysis of the exhaust valve face in diesel marine engine

Smoleńska H., Kończewicz W.

Advances in Materials Science

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2010

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Vol. 10, nr 2(24)

11-18

EN

The exhaust valve from marine diesel engine which was damaged after 2000 hours of service was investigated. In order to prolong the service time the valve face was cladded with cobalt base alloy using laser technique. After failure microstructural and chemical analyses reviled that cladding process was conducted improperly. The chemical composition of the clad layer was far from the designed one and what more completely inhomogeneous. As a result the valve presented different properties in different regions which led to premature failure.

14

Behaviour of the exhaust valve cladding face under the service conditions

Kończewicz W., Smoleńska H.

Journal of KONES

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2009

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Vol. 16, No. 1

265-271

EN

During the ship engine operation one of the key problems is the exhaust valve durability. A special interest is in valve head face because this narrow part of the valve is responsible for tightness. Cobalt base laser cladding layer on the exhaust valve head face have been investigate under real service condition using the laboratory two-stroke diesel engine L22 for two years. During this time the engine was fuelling with both ordinary light fuel and biodiesel fuel. After removing from the valve head from the cylinder head the face surface were fully inspected optically. There were no damages and the surface was shining in the great deal however some dark "spots " on it. The samples made of the used valve head underwent microstructural investigation and hardness measurements. There were no observed substantial microstructural changes neither in the surface of the layer nor in the bulk of the clad. The decrease of the hardness numbers was observed but still clad layer presented higher hardness than steel base. This type ofclad layer underwent intensive laboratory examinations which contained oxidation experiments at different temperatures and corrosion in exhaust gases and with the present service experiment this method of valve head hard facing is suitable for practical applications.

15

Microstructure and properties of the cobalt base clad layers after long time service

Smoleńska H., Kończewicz W.

Advances in Materials Science

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2009

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Vol. 9, nr 4(22)

15-20

EN

The cobalt base laser cladding layers were investigated after two years of service in two laboratory diesel engines. The microstructures of the clads after service did not demonstrated serious degradation process. Chemical compositions of the used layers and changes in hardness were described. These sorts of layers are suitable for long time service with out substantial damages.

16

The resistance investigation of the marine engine exhaust valve using the modelling chamber

Kończewicz W., Smoleńska H.

Journal of KONES

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2008

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Vol. 15, No. 4

255-262

EN

At contemporary technical designs, many equipment and installation are working for a long time and under complex environmental which include mechanical, thermal and chemical loadings. Before the new technical design is accepted for work, it must be carefully investigated in order to evaluate its usefulness for real need. During the ship engine operation, one of the key problems is the exhaust valve durability. A special interest is in valve head face because this narrow part of the valve is responsible for tightness. Very often, the durability of the valve is not sufficient in spite of using heat treated high alloy steels. Surfacing the seat face with different techniques and different resisting materials can increase the durability of valves and also can be useful to repair worn components. Because the ship engine valves are the example of the parts, which are highly mechanical, and chemical loaded and subjected for long service life, the design of the special examination chamber seems to be useful. At this station, the clad layer made by different techniques and from different cladding materials are undergo exhaust gases corrosion and elevated temperature is the factor which accelerates process. In this paper the schematic diagram of the modeling chamber and some results of the investigation are presented. There are comparisons of the microstructure and hardness of the worn valve heads from the real working engine and samples, which were exposed in the chamber. The metallographic method of the analyse and microhardness measurements were used.

PL

We współczesnej technice szereg części urządzeń i instalacji pracuje w długich okresach czasu i w złożonych warunkach obciążenia mechanicznego, termicznego i chemicznego. Próby wprowadzenia nowych rozwiązań technicznych muszą być poprzedzone szczegółowymi badaniami, które stwierdzą przydatność do konkretnych zastosowań. Problemem występującym w przemyśle okrętowym, a dokładniej w procesie eksploatacji silników okrętowych jest trwałość jednego z kluczowych elementów tj. zaworów wylotowych. Z punktu widzenia eksploatacji największą uwagę poświęca się wąskiej powierzchni przylgni zaworu, której dokładność dopasowania decyduje o jego szczelności. Pomimo stosowania stali wysokostopowych obrobionych cieplnie trwałość zaworów jest często niewystarczająca. Aby zwiększyć ich trwałość stosuje się pokrycie przylgni stopami charakteryzującymi się większą odpornością w wyżej wymienionych warunkach pracy. Stopy i technologie powinny także umożliwiać nie tylko wytwarzanie warstw na nowych zaworach, ale także umożliwiać ich regenerację. Ponieważ zawory silników okrętowych są przykładem części silnie obciążonych zarówno mechanicznie jak i chemicznie a czasy ich eksploatacji liczy się w tysiącach godzin stąd pożyteczne wydaje się zastosowanie specjalnie zaprojektowanej komory, w której wykonane różnymi metodami warstwy będą podlegać oddziaływaniu spalin, a podwyższona temperatura będzie dodatkowym czynnikiem przyspieszającym proces degradacji. Jednakże istotna jest ocena na ile przyspieszone procesy w komorze odpowiadają rzeczywistym procesom degradacji. W pracy przedstawiono schemat komory modelowej oraz wyniki badań dla zaworów poddanych korozji w komorze oraz ich porównanie ze zużytymi zaworami po eksploatacji w silniku okrętowym podczas normalnej eksploatacji. Do badań wykorzystano metody badań metalograficznych oraz pomiary mikrotwardości.

17

The resistance investigation of the marine engine exhaust valve using the modelling chamber

Kończewicz W., Smoleńska H.

Journal of KONES

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2008

|

Vol. 15, No. 2

199-206

EN

At contemporary technical designs, many equipment and installation are working for a long time and under complex environmental which include mechanical, thermal and chemical loadings. Before the new technical design is accepted for work it must be carefully investigated in order to evaluate its usefulness for real need. During the ship engine operation one of the key problems is the exhaust valve durability. A special interest is in valve head face because this narrow part of the valve is responsible for tightness. Very often the durability of the valve is not sufficient in spite of using heat treated high alloy steels. Surfacing the seat face with different techniques and different resisting materials can increase the durability of valves and also can be useful to repair worn components. Because the ship engine valves are the example of the parts which are highly mechanical and chemical loaded and subjected for long service life, the design of the special examination chamber seems to be useful. At this station, the clad layer made by different techniques and from different cladding materials are undergo exhaust gases corrosion and elevated temperature is the factor which accelerates process. In this paper the schematic diagram of the modeling chamber and some results of the investigation are presented. There are comparisons of the microstructure and hardness of the worn valve heads from the real working engine and samples which were exposed in the chamber. The metallographic method of the analyse and microhardness measurements were used.

PL

We współczesnej technice szereg części urządzeń i instalacji pracuje w długich okresach czasu i w złożonych warunkach obciążenia mechanicznego, termicznego i chemicznego. Próby wprowadzenia nowych rozwiązań technicznych muszą być poprzedzone szczegółowymi badaniami, które stwierdzą przydatność do konkretnych zastosowań. Problemem występującym w przemyśle okrętowym, a dokładniej w procesie eksploatacji silników okrętowych jest trwałość jednego z kluczowych elementów tj. zaworów wylotowych. Z punktu widzenia eksploatacji największą uwagę poświęca się wąskiej powierzchni przylgni zaworu, której dokładność dopasowania decyduje o jego szczelności. Pomimo stosowania stali wysokostopowych obrobionych cieplnie trwałość zaworów jest często niewystarczająca. Aby zwiększyć ich trwałość stosuje się pokrycie przylgni stopami charakteryzującymi się większą odpornością w wyżej wymienionych warunkach pracy. Stopy i technologie powinny także umożliwiać nie tylko wytwarzanie warstw na nowych zaworach, ale także umożliwiać ich regenerację. Ponieważ zawory silników okrętowych są przykładem części silnie obciążonych zarówno mechanicznie jak i chemicznie a czasy ich eksploatacji liczy się w tysiącach godzin stąd pożyteczne wydaje się zastosowanie specjalnie zaprojektowanej komory, w której wykonane różnymi metodami warstwy będą podlegać oddziaływaniu spalin, a podwyższona temperatura będzie dodatkowym czynnikiem przyspieszającym proces degradacji. Jednakże istotna jest ocena na ile przyspieszone procesy w komorze odpowiadają rzeczywistym procesom degradacji. W pracy przedstawiono schemat komory modelowej oraz wyniki badań dla zaworów poddanych korozji w komorze oraz ich porównanie ze zużytymi zaworami po eksploatacji w silniku okrętowym podczas normalnej eksploatacji. Do badań wykorzystano metody badań metalograficznych oraz pomiary mikrotwardości.

18

Gas corrosion influence on the exhaust valve face of the marine engine

Kończewicz W., Daszczyk A., Smoleńska H.

Journal of KONES

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2008

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Vol. 15, No. 4

245-253

EN

The main factor, which influences on the proper work of the marine engine, is the valve tightness. Especially in the case of the exhaust valve, lack of the tightness leads to the worsening of the combustion process and above all causes the acceleration of the valve destruction by the valve face degradation. The valve head is mating with the face of the valve seat and they make cyclic tight contact during the engine run. The valve seat is placed in the cylinder head, which is cooled with water so the work conditions of the seat and head are different. When the exhaust valve is open the outlet of the hot exhaust products of combustion can change extremely properties of the materials of the face surface. It can lead to the geometrical changes as a result of mechanical forces and exhaust gases. The indicators of those changes are shape deviation and roughness. During the service time because those changes take place at non uniform way because of complex co-operation in the hot and aggressive gas atmosphere. In this paper some examples of the roughness measurements were presented. The measurements were taken for the valve face for a new ones (made from steel and with clad layer) and after exposition for aggressive environment in the engine and during oxidation in ambient air. The results of the straightness and roughness measurements confirm the environmental degradation of the valve face.

PL

Istotnym czynnikiem wpływającym na poprawność funkcjonowania silnika okrętowego jest szczelność zaworów. Szczególnie w odniesieniu do zaworów wylotowych brak szczelności prowadzi do pogorszenie warunków spalania a przede wszystkim do przyspieszonego zniszczenia zawory poprzez uszkodzenia przylgni. Przylgnia grzybka zaworowego współpracuje z przylgnią gniazda zaworowego tworząc cykliczny szczelny kontakt stykowy w trakcie pracy silnika. Przylgnia gniazda jest osadzona w głowicy zaworowej chłodzonej wodą więc warunki jej eksploatacji są odmienne od warunków pracy grzybka zaworowego. Faza otwarcia zaworów wylotowych w której dochodzi do wylotu gorących produktów spalania paliwa z tulei cylindrowej doprowadza do ekstremalnych zmian własności materiału z którego wykonana jest przylgnia grzybka co następnie wpływa na zmiany struktury geometrycznej powierzchni przylgni w trakcie styku z powierzchnią gniazda pod wpływem dużych sił od ciśnienia sprężanego powietrza oraz spalin. Wskaźnikami zmian struktury geometrycznej powierzchni przylgni grzybka zaworowego są odchyłki kształtu oraz parametry chropowatości powierzchni. W trakcie eksploatacji grzybka zmiany stanu przylgni zachodzą nierównomiernie co potwierdza złożoność współpracy w gorącym agresywnym środowisku gazów. W pracy przedstawiono przykładowe wyniki pomiarów dla przylgni w stanie wyjściowym, po pracy w silniku badawczym i po utlenianiu w spokojnym powietrzu oraz wynikające stąd wnioski Pomiary prostoliniowości tworzącej stożka kształtującej przylgnię oraz parametrów chropowatości eksploatowanego grzybka potwierdzają degradacyjny wpływ środowiska na jej stan.

19

Effect of tungsten content on the corrosion resistance of the cobalt base PTA cladding layers

Kończewicz W., Smoleńska H.

Journal of KONES

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2007

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Vol. 14, No. 2

247-252

EN

The cobalt base PTA cladding layers which were built up on the exhaust valve head face of the heavy loaded marine diesel engine have been investigated. The layers were produced from three sort of the powders of different tungsten amounts (4.9, 5.3 and 9 wt. %). Multilayer cobalt base clads after turning and grinding underwent the treatment at the high temperature and different aggressive atmospheres. The oxidation at 650 centigrade for 100 hours and corrosion in exhaust gas condition at temperature about 700 centigrade for similar times were investigated. In order to describe the influence of tungsten on clads properties the cross sections microstructures were observed both close to the surface and to the steel/clad interface as clad and after corrosion, the distribution maps of the alloying elements and chemical microanalysis of the different regions and conditions were performed and also micro hardness distributions were made. It was found that different amount of tungsten did not influence significantly on the microstructure neither as clad state nor after corrosion treatment. However the higher tungsten amount resulted in higher hardness of the layer.

PL

Badaniom poddano napawane plazmowo warstwy wytworzone na powierzchni przylgni zaworów wylotowych silnie obciążonych silników Diesla stosowanych w okrętownictwie. Jako materiał do napawania zastosowano trzy rodzaje proszków wykonanych ze stopów na bazie kobaltu i chromu zawierających różne ilości wolframu (4.9, 5.3 i 9% masowych). Wykonane napoiny wielowarstwowe po odpowiednim przygotowaniu poddano działaniu podwyższonej temperatury i środowisk korozyjnych. Badania przeprowadzono w powietrzu - utlenianie w temperaturze 650 C przez 100 godzin i w środowisku spalin w temperaturze ok. 700 C w zbliżonym czasie. Dla określenia wpływu zwartości wolframu na własności warstw napawanych przeprowadzono badania mikrostruktury na przekroju warstw po napawaniu i po korozji, określono mapy rozkładu pierwiastków w strefie przypowierzchniowej napoin w na granicy napina podłoże stalowe, określono składy chemiczne w mikroobszarach w różnych rejonach napoin dla poszczególnych stanów warstwy oraz zmierzono mikrotwardość na przekroju warstwy w różnych stanach. Stwierdzono, że różnice w składzie chemicznym proszków nie wpływają w sposób znaczący na strukturę warstwy ani w stanie wyjściowym ani po korozji w różnych środowiskach gazowych. Natomiast obserwuje się wyższą twardość warstw wykonanych z proszku o wyższej zawartości wolframu.

20

Analiza własności napawanych laserowo powierzchni przylgni zaworów wylotowych silników okrętowych po korozji w powietrzu i w gazach spalinowych

Smoleńska H., Kończewicz W.

Inżynieria Materiałowa

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2006

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Vol. 27, nr 3

536-539

PL

Przedmiotem opracowania jest badanie morfologii napawanych laserowo warstw z proszku na bazie kobaltu zawierającego jako główne składniki chrom (29%) i wolfram (5,3%) o niskiej zwartości niklu. Przeanalizowano budowę i skład chemiczny warstw po napawaniu oraz oceniono zmiany po utlenianiu w temperaturze 750°C oraz po korozji w gorących gazach spalinowych silnika L-22. Badania obejmowały analizę mikrostruktur za pomocą mikroskopu świetlnego i elektronowego mikroskopu skaningowego; analizę składu chemicznego, warstwy napawanej oraz warstw utlenionych oraz skorodowanych w środowisku spalin, za pomocą przystawki EDS, a także określenie mikrotwardości na przekroju warstw. Przeprowadzone badania wykazały znaczną odporność napawanych warstw zarówno na korozje w spalinach jak i na utlenianie.

EN

The morphology of the laser clad layers made of the powder containing Cr (29%) and tungsten (5,3%) and low amount of Ni were investigated. The microstructure as clad layers were analyzed and the changes after oxidation at 750°C and corrosion in hot exhaust gases produced by engine L-22 were evaluated. Researches contained light and scanning electron microscope, EDS analyze and hardness measurement on the crossection. The result proved good corrosion resistance for both oxidation and exhaust gases conditions.