Vliv indexu hustoty na pozezitu slévárenských slitin Al-Si

Influence of the Density-Index on the Porosity in Al-Si Casting Alloys

conference paper

en

The principle of this experiment was in an analysis of the influence of the Density Index and different cooling rate on the porosity according to metallurgical changes of molten metal (gassing, degassing). Simple castings made from AlSi9Cu3 alloy were poured into permanent mould and sand moulds to get a different cooling rates. Porosity was measured on the microstructure of each sample. For this experiment "the reduced pressure test" was used. Significant values were shape factor, size and distribution of the bubbles. The mechanical properties such as tensile strength (Rm) and yield strength (Rp0,2), were measure on these samples. The tensile strength is seriously decreased as the hydrogen concentration increases. The yield strength is only very slightly affected.

Princip experimentu spočívá v analýze vlivu indexu hustoty a rozdílné rychlosti ochlazování na porezitu v závislosti na metalurgické změny tekutého kovu. Aby se dosáhlo rozdílných rychlostí ochlazování, byl jednoduchý odlitek ze slitiny AlSi9Cu3 odlit do kovové a do pískové formy. Porezita byla měřena na metalografických vzorcích. Rozhodující hodnotou je množství a tvar vyloučených bublin. Na zkušebních vzorcích byly zjišťovány mechanické vlastnosti. S rostoucím obsahem vodíku se strmě snižuje pevnost v tahu, mez kluzu je ovlivněna jen nevýznamně.

The principle of this experiment was in an analysis of the influence of the Density Index and different cooling rate on the porosity according to metallurgical changes of molten metal (gassing, degassing). Simple castings made from AlSi9Cu3 alloy were poured into permanent mould and sand moulds to get a different cooling rates. Porosity was measured on the microstructure of each sample. For this experiment "the reduced pressure test" was used. Significant values were shape factor, size and distribution of the bubbles. The mechanical properties such as tensile strength (Rm) and yield strength (Rp0,2), were measure on these samples. The tensile strength is seriously decreased as the hydrogen concentration increases. The yield strength is only very slightly affected.

Density Index, porosity, cooling rate, shape factor, reduced pressure test

01.04.2004

Fachschaft Metallurgie und Werkstofftechnik der RWTH Aachen

Aachen

11. Internationaler Studententag der Metalurgie

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270–274

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