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Przykład obróbki cieplnej odlewów z żeliwa wysokochromowego

Siekaniec D., Szczęsny A., Kopyciński D.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 4 spec.

109--112

PL

Żeliwo wysokochromowe jest powszechnie stosowanym materiałem w przemyśle górniczym i mineralnym, gdzie wymagana jest duża odporność na zużycie ścierne. Swoje dobre właściwości zawdzięcza obecności w mikrostrukturze twardych węglików. Żeliwo chromowe poddawane hartowaniu ma w praktyce osnowę austenityczną, austenityczno-perlityczną lub perlityczną. Istotnym procesem w czasie obróbki cieplnej jest tzw. destabilizacja austenitu, jest on ważny ponieważ dopiero po jego zajściu może nastąpić przemiana martenzytyczna. W zależności od szybkości chłodzenia, które następuje po procesie destabilizacji austenitu, może powstać perlit, bainit i martenzyt. Przeprowadzone badania dotyczyły określenia wpływu szybkości chłodzenia odlewów z żeliwa wysokochromowego po obróbce cieplnej, na mikrostrukturę i twardość. Badaniu zostało poddane żeliwo wysokochromowe o zawartości 27%Cr i 2,7%C. Przeprowadzono zabieg hartowania z temperatury 950 °C w czasie 4h, następnie odlewy poddano trzem wariantom chłodzenia – w wodzie, w kąpieli solnej i na powietrzu. Zbadano i porównano mikrostrukturę oraz twardość odlewów dla różnych wariantów chłodzenia.

EN

High Chromium Cast Iron (HCCI) is widely use in mining and mineral industry, where abrasive resistance is a principal requirement. Its good properties thanks to the hard eutectic carbides occurring in the microstructure. The effect of heat treatment on HCCI was a subject of many research. High Chromium Cast Iron have an austenitic, austenitic-pearlitic or pearlitic matrix. An important process during the heat treatment is austenite destabilization, thus until after it conduct the martensitic transformation can occur. Depending on the cooling rate that follows the process of destabilization of austenite, perlite, bainite and martensite may form. The present work, aimed at studying the influence of cooling rate after heat treatment, on the microstructure and hardness. The study were carry out on samples of High Chromium Cast Iron containing 27%Cr i 2,7%C. Samples were subjected to the tempering treatment at the temperature of 950°C for 4 hours and three variants of cooling – in water, in a salt bath and on air. Examined and compared the microstructure and hardness of castings for different variants of cooling.

2

Effect of T6 Treatment Parameters of AlZn10Si7MgCu Alloy on Change of its Hardness and Impact Strength

Pezda J.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 1 spec.

143--146

EN

Among alloys of non-ferrous metals, aluminum alloys have found the widest application in foundry industry as a competitive alternative of ferroalloys. One from methods to improve mechanical properties of aluminum alloys is a heat treatment consisting in heating a material to solutioning temperature, keeping the material in such temperature, and subsequent rapid cooling and natural or artificial ageing. In the paper are presented test results concerning effects of the T6 heat treatment, comprising solutioning and artificial ageing, on hardness and impact strength of the AlZn10Si7MgCu alloy poured into metal moulds. Temperature ranges of solutioning and ageing treatments were selected on the base of recorded curves from the ATD method. Basing on three-stage plan of the investigations with four variables one determined range of the heat treatment parameters, what is a condition of obtainment of required HB hardness of the investigated alloy. Further investigations shall concern correction of obtained results with respect to the HB hardness and impact strength, obtained for selected castings of machinery components.

3

Heat treatment of EN AC-AlSi13Cu2Fe silumin and its effect on change of hardness of the alloy

Pezda J.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

131--134

EN

Wide application of aluminum casting alloys is connected with their very good physical and technical properties. Within such group of alloys, silumins play important role in automotive and aviation industry, as well as in another branches of technique, because the silumins enable casting of complicated shapes. The most important parameters which predetermine mechanical properties of a material in aspects of suitability for castings of machinery components are: tensile strength (Rm), elongation and hardness. Alloys based on equilibrium system of Al-Si comprise additional constituents (e.g.: Mg, Cu) enabling, except modification, improvement of mechanical properties, obtained in result of heat treatment. In the paper are presented results of investigations concerning effect of the heat treatment on change of hardness (HB) of the EN AC-AlSi12Cu2Fe alloy. Investigated alloy was melted in an electric resistance furnace. Run of the crystallization was presented with use of the thermal-derivative method (ATD). This method was also implemented to determination of heat treatments temperature range of the alloy. Performed heat treatment gave effect in change of the hardness. Performed investigations have enabled determination of heat treatment parameters range, which conditions suitable hardness of the investigated alloy.

4

Wpływ dodatku tytanu na mikrostrukturę i twardość stopu AlSi11

Mola R., Konieczny M., Depczyński W.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Techniczne

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2009

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Z. 13

288--294

PL

W prezentowanym artykule badano wpływ dodatku tytanu na mikrostrukturę i twardość stopu AlSi11. Wykonano stopy o zawartości 0,4%Ti i 1%Ti, które odlewano do metalowej formy. Z uzyskanych stopów wycięto próbki do badań strukturalnych, które prowadzono na mikroskopie optycznym i mikroskopie skaningowym. Wykonano pomiar twardości stopów AlSi11 z dodatkiem tytanu. Stwierdzono wzrost twardości stopów wraz ze wzrostem zawartości tytanu.

EN

In this study, the influence of titanium addition on the microstructure and hardness has been investigated. The AlSi11 alloys with 0,4%Ti and 1%Ti were prepared. This alloys were casting in the metal mold. Metallographic observations have been made by the optical microscopy and scanning electron microscopy. The addition of the Ti to AlSi11 alloys leads to an increase in hardness values.

5

Wpływ twardości i mikrostruktury stopów aluminium na udarność

Gorockiewicz R.

Archiwum Odlewnictwa

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2003

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R. 3, nr 8

279--286

PL

Na przykładzie stopów aluminium (bez obróbki cieplnej i obrobionych cieplnie) zbadano wpływ twardości i mikrostruktury na udarność.

EN

On the example of alloys the aluminium (without the heat-treatment and of worked thermally) one examined the influence of the hardness and microstructures on their impact resistance.