INFLUENCE OF MOLD ROTATION SPEED DURING CENTRIFUGAL CASTING ON THE STRUCTURE AND MECHANICAL PROPERTIES OF HOLLOW CASTINGS

Deformable Al-Mg system alloys are the most widely used among others, applied for pressed and rolled products manufacturing, particularly for aerospace and cryogenic technology (up to -253 ºС). Increasing thermal stability and strength up to σ0,2 > 400-450 МPа became one of the main tasks that may be solved by additional alloying with refractory, transition metals (TM) and rare earth metals (REM), as well as in influence of specific crystallization processes like centrifugal casting. The significant parameter in the process of centrifugal casting is the rotational speed of the mold. The presents research of the centrifugal casting technological parameters influence on the structure and mechanical properties of hollow castings made of aluminum alloy AlMg5, which is doped by small additions of transition and rare earth metals. By using numerical simulation, it was determined that the installation of a foam ceramic filter in the pouring cup of a centrifugal casting machine contributes to the laminarization of the melt flow at the mold entrance. With an increase of the mold rotation speed from 1100 to 2000 rpm, the thickness of the loose inner layer and its delamination decreases, microstructure refines and the mechanical properties of hollow castings increase. Compared to stationary mold casting, the mechanical properties of centrifugal castings increase: at 1500 rpm σ0,2 - by 10%, σВ - by 25%, δ - by 3 times, at 2000 rpm σ0,2- by 18%, σВ – by 31%, δ – by 4 times. The results of the work indicate the expediency of using centrifugal casting method to improve the operational characteristics of products made of Al-Mg systems alloys.