Casting, Semi-Solid Forming and Hot Metal Forming

s a common process for formingwith low melting points. It is particularly suited for the high-volume production of comparatively complex near-net shape parts. Thixocasting via the HPDC route is currently being commercially used by V-Forge (92) and SAG (93) while the rheocasting route is being pursued by a number of research centers and to a lesser extent commercially significant solid fraction use the behavior of the slurry to achieve laminar filling and hence produce high-integrity castings. The high-pressure die casting oflurries can be achieved using cold chamber HPDC machines with horizontal injection and horizontal clamping, vertical injection with vertical clamping, and vertical injection with vertical clamping.

More recently, the slurarticular low solid fraction slurries, has been used in the in-sand castings as well

High-pressure die casting

High-pressur(HPDC) is a very commonly used process for creating structural components, especially in Mg. In this process, a metal die having a cavity with the negative geometry of the part is created; simple dies usually consist of two matching halves, while more complex dies can add sliding features that create holes and undercut areas. The die is mounted onto a machine capable of injectiat high velocities. The die cavity is closed, molten metal is poured into a shot sleeve, the sleeve opening is closed, and a ram moves forward to force the metal into the die in a very short time (10–100 ms), generating high levels of applied pressure. Following this, the ram pressure is maintained for a short time; often, active cooling occurs as internal water passages in the die are activated. Then, the pressure is released and the ram is withdrawn; the die opens and ejector pins push out part. The process cycle for the HPDC process is usually very rapid; for example, a current 110 lb HPDC V6 engine block has

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