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Wyszukujesz frazę "cobalt alloy" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Behaviour of the exhaust valve cladding face under the service conditions
Autorzy:
Kończewicz, W.
Smoleńska, H.
Powiązania:
https://bibliotekanauki.pl/articles/244130.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
exhaust valve
laser cladding
cobalt alloy
service wear
Opis:
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.
Źródło:
Journal of KONES; 2009, 16, 1; 265-271
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on structures and properties of the laser cladding exhaust valve after service
Autorzy:
Kończewicz, W.
Krużycki, P.
Smoleńska, H.
Powiązania:
https://bibliotekanauki.pl/articles/244029.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
exhaust valve
laser cladding
cobalt alloy
service wear
Opis:
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.
Źródło:
Journal of KONES; 2010, 17, 3; 211-216
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Impact of Material Selection on Durability of Exhaust Valve Faces of a Ship Engine – A Case Study
Autorzy:
Smoleńska, Hanna
Kończewicz, Włodzimierz
Bazychowska, Sylwia
Powiązania:
https://bibliotekanauki.pl/articles/102904.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
cobalt alloy
laser cladding
exhaust valve
stop kobaltu
napawanie laserowe
zawór wydechowy
Opis:
Two alloys were used in order to extend the service life of marine engine exhaust valve head. Layers of cobalt base alloys were made of the powders with chemical composition as follow: the layer marked L12; C-1.55%; Si-1.21%; Cr-29.7%; W-9%; Ni-2%; Mo<0.01%; Fe-1.7%; Co-54.83% and the layer marked N; C-1.45%; Co-38.9%; Cr24.13%; Ni-10.43%; W-8.75%; Fe-7.64%; Mo-7.56%; Si-2.59%. Base metal was valve steel after heat treatment. It was consisted of: C-0,374%; Cr-9,34%; Mn-0.402%; Ni-0.344%; Si-2.46%; Mo-0.822%; P-0.0162%; S-0.001%. Layers on the valve faces were produced by laser cladding using the HPDL ROFIN DL020 laser. Grinding treatment is a very popular form of regeneration of seat and valve plug adhesions. Properly performed grinding operation ensures dimensional and shape accuracy of the surface from 7 to 5 accuracy class and surface roughness Ra not less than 0.16 μm, depending on the object and method of grinding. The 75H and 150S types are a significantly simplified form of valve plug face grinders. Finishing treatment was carried out with a Chris-Marine AB75H sander on a sanding stand equipped with a compressed air system - the stand was designed by the author. The sander has been set up to the surface of the valve stem so that the grinding angle of the valve faces is 30°+10°. A flat grinding wheel T1CRA54–K was used for machining. The plunge feed was 0.01 mm/rev. The thickness of the welded layer after grinding was 1.2 mm. Both valves were installed in the ship’s engine and were used in real life. After 2000 hours of operation, the valve marked N was damaged. The valve marked L12 showed no damage and was in operation for the next 1000 hours.
Źródło:
Advances in Science and Technology. Research Journal; 2020, 14, 3; 165-174
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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