Abstract: In order to solve the problem of expensive aluminium-type thermite currently used for ingot casting at Pangang's Steelmaking Plant, a new and cheap substitutional thermal insulation agent is developed. The heat transfer-process of ingot head, mechanism of shrinkage-proof action and property of shrinkage-proof agent are disscussed. A few years' production practice show that the covering agent performance is equal to that of aluminium-type thermite, and the quality of steel comforms to current standards.