Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 4

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: low alloyed steels

Sortuj według:

Ogranicz wyniki do:

Electrochemical corrosion studies of steels after plasma nitridation and oxidation

100%

Oppelt J. , Karjalajnen P. , Blahetová M. , Číhal V.

2006

tom z. 88

87-92

Sintering of Ni-Mo-W steels and their properties

75%

Dobrzański L. A. , Otręba J. , Actis Grande M. , Rosso M.

2007

tom Vol. 28, nr 2

77-82

Purpose: The paper focuses on microstructural and mechanical characteristics of Ni-Mo and Ni-Mo-W sintered steels with increasing amount of tungsten, low and high addition of carbon. Design/methodology/approach: Prepared mixes of powders have been compacted at 700 MPa and sintered in a vacuum furnace with argon backfilling at 1120°C for 60 minutes; after sintering rapid cooling has been applied with an average cooling rate of 2,5°C/s. Produced sets of samples have been studied by scanning electron microscopy (SEM) with EDS for phase distribution and mapping and light optical microscopy (LOM) for microstructure observations. Mechanical properties such as impact energy, microhardness and wear rates were evaluated depending on chemical composition and the effect of applied sintering process with rapid cooling. Wear resistance was investigated using both pin on disk and disk on disk tests. Findings: The highest value of impact energy was achieved for set of steels with smaller amount of carbon. It was noticed that the presence of tungsten didn't differ much the results. The situation was opposite in the case of microhardness, where the best results were obtained for set with addition of 0.6%C and reached 452 HV0.1. The microstructure of all investigated alloys was mainly martensitic with minor presence of bainite in the set of steels containing low addition of carbon. Research limitations/implications: According to the powders characteristic, the applied cooling rate seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of tempering process. Originality/value: The effect of small additions of W and WC to low alloyed steels, especially in terms of hardenability and wear resistance, was investigated.

Microstructural characteristic and mechanical properties of Ni-Mo-(W) steels

63%

Dobrzański L. A. , Otręba J. , Actis Grande M. , Rosso M.

2006

tom Vol. 18, nr 1-2

347--350

Purpose: Purpose of this paper was to examine the role of tungsten on properties of two different carbon levels pre-alloyed steel powders. Microstructural characteristic and mechanical properties of sinter-hardened Ni-Mo steels with increasing amount of tungsten (from 0 to 0.3% wt.) were taken under consideration. Design/methodology/approach: Powder mixes (Ni-Mo, Ni-Mo-W) have been compacted at 700MPa and sintered in a vacuum furnace with argon backfilling at 1120°C for 60 minutes. Rapid cooling has been applied with an average cooling rate of 2.5°C/s. Obtained samples were analyzed by scanning microscopy with Energy dispersive spectroscopy (EDS) for phase distribution and mapping and light optical microscopy for observations of the microstructure. Charpy impact test, three-point bending, microhardness and pin-on-disk tests were used. Findings: The effect of chemical composition and applied vacuum sintering with rapid cooling were studied in terms of mechanical properties, focusing in particular on impact energy, hardness and wear resistance. The results achieved after the investigation of Ni-Mo and Ni-Mo-W sinter-hardened steels with low and high carbon content proved that applied process of sintering under vacuum and rapid cooling brought expected outcome. Research limitations/implications: According to the powders characteristic, the applied cooling rate seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of tempering process. Originality/value: The effect of small additions of W and WC to low alloyed steels, especially in terms of hardenability and wear resistance, was investigated.

Mechanizm i kinetyka korozji żelaza i jego stopów w układzie H2O - NaCl - CO2 - H2S. Badania w warunkach laboratoryjnych i w polskich instalacjach geotermalnych

63%

Banaś J. , Łukaszczyk A. , Mazurkiewicz B. , Solarski W.

tom nr 3

94-105

Artykuł jest przeglądem naszych badań w zakresie mechanizmu korozji i pasywacji żelaza, stali konstrukcyjnych oraz stali stopowych w systemie H2O - NaCl - CO2 - H2S, w podwyższonej temperaturze i podwyższonym ciśnieniu. Praca ma duże znaczenie dla doboru stali odpornych na korozję, przeznaczonych do budowy instalacji geotermalnych. Zaproponowany został mechanizm korozji stali konstrukcyjnych, wyjaśniony wpływ zawartości chromu oraz obróbki cieplnej na odporność korozyjną stali niskostopowych. Praca przedstawia również właściwości elektrochemiczne (pasywację) stali stopowych w wodzie o silnej mineralizacji (solance). Artykuł omawia zarówno badania laboratoryjne (w autoklawie) jak i w instalacji przemysłowej. Te ostatnie pozwoliły na uzyskanie charakterystyki elektrochemicznej stopów w warunkach naturalnych, w bardzo dużych przepływach (do 2 m/s).

The paper presents the review of our investigations of the mechanism and kinetics of corrosion and passivation of iron, carbon steels and chromium steels in the H2O - NaCl - CO2 - H2S system, in elevated temperature and at high pressure. The work is very important for the selection of corrosion resistant steels for geothermal plants. Corrosion mechanism of carbon steel is discussed and the influence of chromium content in the steel and the effect of thermal treatment of the alloys on the mechanism of anodic layer formation and corrosion resistance of the alloys are explained. The paper presents also the passive behavior of stainless chromium steels in thermal water with high salinity (brine). The investigations were performed in laboratory (autoclave) and in field conditions, in Polish geothermal power plants (electrochemical measurements at high pressure and high water flow rate, up to 2 m/s).