PREVENTION OF STARTING CRACKS IN AL-BILLETS: FEASIBLE METHODS FOR FLOAT AND SPOUT DC-CASTING

摘要

Hot crack formation especially starting crack formation in butts of DC cast extrusion billets often causes rejections, in particular while casting high-alloyed aluminum. The prevention of such starting cracks can reduce the rejection rate. Crack formation is well investigated in theory and many techniques for crack prevention are used in practice. Nevertheless starting cracks are a problem in DC casting. This paper presents an investigation of methods for prevention of starting cracks in Al-billets production using float and spout DC-casting. Starting with the results of former examinations and practical experience these methods are tested for their suitability for crack prevention. The main focus is on the application of all technologies to the float and spout DC-casting. The paper presents the research methods, the results of crack prevention and the real implementation in practice.