Acta Technica Corviniensis

1.REMUS BOBOESCU, 2. ION SPOREA, 3. ILARIE BORDEAŞU,4.ADRIANA TOKAR, 5 VICTOR BUJORTHE USAGE OF TYPE SILIUMINIU ALLOYSWITH MAGNESIUM FOR CASTINGA VERY LARGE USED PIECESAbstract:ATSi7Mg aluminum alloy is subjected to the processes of hardening and aging. The structuraltransformations are related mechanical properties of the alloy. The prezence of the Mg2Si phase isthe main cause of increasing resistance of alloys Al-Si-Mg, but with the presence of stable phase Mg 2 Sireduces refractivity of ternary alloys.Keywords:aluminum alloy, mechanical properties, magnesiumINTRODUCTIONAmong the advantages of alloys siluminiumATSi 12 ; ATSi 10 MnMg; ATSi 7 Mg; ATSi 7 MgTi is theused in humid atmosphere like maineatmosphere As the concentration of Si growththere is a decrease of the linear thermalexpansion coefficient, but to obtain a raftstructure raft in the cast [1] [2] [4] [5] [6] (thematerial is fragile and difficult to process).For finishing the structure, increase themechanical resistance and improve mechanicalmachining by cutting of type AAT siluminium(hipo and eutectic) is added to Na and Cl andsalts containing F and Na, S, P, etc.. in the alloy.The hypereutectic alloys have much Si I in thestructure and is difficult to be modified with saltscontaining Na. A greater effect in modifyingthese alloys siluminiu hypereutectic is obtainedwith substances containing S or P [6] [7] [8] [9].SYSTEM ALLOYS IN AL-SI + EA (ALLOYINGELEMENTS)System Al-Si alloys + Ea is one of most used inthe casting aluminum alloy of great importancepieces because it possess superior mechanicaland technological proprieties than other castaluminum alloys (AAT).The most typical alloy system Al-Si-Mg is widelyused in casting of ATSi 7 Mg (6-8% Si, 0.25-0.4% Mg,the rest). This alloy is used both in the hardeningstate (T4) and after partial aging (T5). Is is usedfor castings pieces with thin walls and complexshapes used in the condition of medium loadedforces (body pump, etc.). The advantages of alloyATSi7Mg are: good casting properties (highfluidity, minimum linear contractions) like asATSi 12 ; the tendency of formation of small crackshot high temperature; good mechanical strengthand satisfactory plasticity; compared withATSi10MnMg not require autoclaves to pressure© copyright FACULTY of ENGINEERING – HUNEDOARA, ROMANIA 41