GB521824A - Improvements in or relating to the centrifugal casting of metals - Google Patents

Abstract

521,824. Mould materials. DEUTSCHE EISENWERKE AKT.-GES. Nov. 29, 1938, No. 3,4724. Convention date, Jan. 10. Addition to 441,335. [Class 83 (i)] A lining for centrifugal moulds comprises, in addition to the small bars or flakes, as in the parent Specification, metallic or non-metallic grains. When casting steel or other metals having a high melting point the grains consist of refractories such as quartzite, magnesite, aluminium nitride, or calcined alumina and should be between 0.5 and 2 mm. in size. Smaller grains are used when casting brass. If the grains are disposed near the mould wall a slower speed of rotation is sufficient than is necessary when a mixture is used and if they form the inner face a higher speed. Permeability to gas is increased by uniformity of grain size and thermal insulation by increase in size. Binders may be used if they do not fill the interstices and practically cease to bind after the casting operation, e.g., silica gel, alkyde resin in acetone, or sulphuric acid and sulphite lye with sand or ceramic grains. The lined mould may be heated from the inside to remove volatile constituents and reduce the loss of heat when casting steel &c. In another modification mixed or granular material free from binder may be applied to a mould lined with mixed material including a binder, this layer remaining in the mould when the casting is drawn.