Improving Quality of the EN AC-43300 (AlSi9Mg) Alloy Destined for Castings of a Pump Casings

Among non-ferrous alloys, the aluminum alloys have found the most widespread applications within foundry industry. Hypoeutectic silumin of the AlSi9Mg grade is commonly used for large, heavy duty machinery castings with complicated shape and high strength. From technical point of view, tendency to creation of coarse structure can be considered as a drawback of such alloy, what can have adverse effect on properties of the alloy. To obtain optimal structure of the castings and to assure improvement of their mechanical properties, the most effective treatment to perform is modification. Quality of performed modification treatment depends on proper dosing of inoculant and maintaining suitable temperature and time of keeping the alloy before pouring. In the paper are presented test results of crystallization course of refined and modified silumin of the EN AC–43300 (AlSi9Mg) grade, used in castings of pump casings. It has been determined an effect of performed processes of refining and modification on the mechanical properties (R_m, A₅, HB and KCV), additionally, metallurgical tests of the alloy have been performed. Basing on analysis of obtained results, the most advantageous modification variant, which is suitable for castings of pump casings and complying with requirements of customers, has been selected.