Observations of Fill Behavior, Surface Quality, Weldability and Performance of SSM Aluminum Structural Parts Produced On Real-Time and Three-Phase Machines

摘要

Recently, several new developments in semi-solid metal (SSM) processing have suggested that injection power, rather than real-time control, is by far the dominant factor in achieving high quality structural aluminum alloy parts. Coupled with new concepts in raw material preparation, these developments suggest that SSM processing may achieve a significant upsurge in applications in the coming years as implementation on the factory floor becomes simpler. In addition to the above, well-designed thermal management systems and application of high vacuum also present opportunities to produce thin-wall, high quality parts from premium alloys, which can be fully heat treated to offer attractive physical and mechanical properties. This paper presents a comparison of benchmark parts produced under a variety of conditions and on both real-time and three-phase machines. The advantages of high vacuum systems for the production of SSM parts are analyzed, as are the benefits of adequate oil heating/cooling design. Practical guidelines for runner design, venting, overflows and lubrication are discussed. The paper provides data from both T5 and full T6 heat treated parts as well as welding studies, polishing and chrome plating. SSM processing is shown to be an effective approach not only for structural parts, but also for surface critical applications. High vacuum is a tool allowing very thin section sizes to be cast without loss of part integrity.