Abstract

The effects of vacuum centrifugal casting in manufacturing 80mm diameter Ti-48Al-2Cr-2Nb turbocharger turbine wheel have been studied using centrifugal caster and surface analysis technique. Based on the good compatibility to high temperature environment, Ti-48Al-2Cr-2Nb is used for high speed materials of military equipment. Recently, centrifugal casting method is noticed to manufacture cost effective high temperature materials. In this paper, the effects of the vacuum centrifugal casting and optimum conditions are discussed based on surface analysis. According to the results, the diameter of the gate needs to be 30mm and RPM should be 260. The mode of vacuum centrifugal casting is deeply related to the gate size, RPM, and cooling method. Therefore, it is considered that pouring temperature, preheating temperature, RPM, and cooling method play important roles in manufacturing of Ti-48Al-2Cr- 2Nb turbocharger turbine wheel. In this study, by using a ceramic mold in which Ti powder is mixed with Al2O3, it was confirmed that the alpha-case layer was formed in the hardness elevation area in the area less than 50μm on the surface.

Keywords: Vacuum centrifugal casting; Ti-48Al-2Cr-2Nb;Turbocharger;Turbine wheel