METHOD FOR MAKING THICK-WALL TUBE CASTINGS OF REFRACTORY ALLOYS Russian patent published in 2000 - IPC

FIELD: foundry. SUBSTANCE: method comprises steps of making casting mold of tubular blank with use of investment pattern from refractory oxide materials with ethylsilicate binder; placing mold on layer of high heat conductance filler in flask; molding inner part of casting mold with high heat conductance filler; molding space between outer portion of casting mold and flask with low heat conductance filler; calcining prepared mold; placing hot casting mold with flask on flask bottom and molding space between flask and flask bottom with high heat conductance filler. Relation of thickness values of low heat conductance and high heat conductance fillers is equal to 1: 1 in lower part of mold and it is equal to 1.5:2.1 in upper part of mold. Flask bottom with flask is placed in melting-pouring apparatus and it is poured in vacuum with nickel or cobalt base alloy. Crystallization of thin-wall tube castings in axial and radial directions is realized at constant heat removal. EFFECT: possibility of making castings without shrinkage defects and without liquation of easy-to-melt components of alloys. 1 dwg, 2 tbl, 1 ex