To make the corner castings parts smooth transfer, prevent the thick sections to thin sections of a sharp transition, to reduce the metal flow in the Angle shaped by the vortex of slag, iron beans and bubble. Especially not because of the Angle of stress concentration and the Angle in shell overheat, die material and liquid metal in the slow cooling and make the casting and the casting defects such as cracks, scarring.
On the corner castings, whether parallel or intersecting two walls, and no matter whether the thickness, the joint (except parting surface) should be done with rounded corner castings.
Corner castings the rounded smooth transfer is not too small. But the rounded too big and will increase because of the new hot section and cause shrinkage cavity, shrinkage defects. According to production practice, therefore, for investment casting foundry radius (R) generally take corner castings through two wall thickness (A, B) (1/3 ~ 1/5) of the sum of The Times, Namely R=1/3-1/5（A+B）
Parts of flange, flange outer edge and parting surface, if no special requirements, should not make a rounded corners, to simplify the structure and reduce the amount of modified corner castings.