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Casting technology developmentshave led to a manufacturing process that allows the casting of thin wall (2-3mm) heat resistant ferritic stainless steel exhaust manifolds which can replace stamped and tubular weldments as well as iron castings where temperature requirements are increased. This casting process combines the thin wall and clean metal benefits of the counter gravity, vacuum-assist casting process using thin, light-weight bonded sand molds supported by vacuum-ridgidized sand. This combination is called the LSVAC (Loose Sand Vacuum Assisted Casting) process, a patented process. This process will significantly contribute to the growth of near-net shape steellstainless steel castings for automotive and allied industries. For exhaust manifolds, a modified grade of ferritic stainless steel with good oxidation resistance to 950°C in high dew point synthetic exhaust gas atmospheres was developed.

An analysis of the long range potential for improvement of aluminum castings for use in automotive applications was made. Comparisons of lost foam, semi-permanent (SPM), and sand casting were done using cylinder heads as the test configuration. The casting processes were compared on the basis of tensile properties, as well as their basic capabilities to provide the highest strength. It was found that, while all three processes are very useful, sand casting can be used to make the highest properties in a wide variety of alloys. Countergravity casting sand molds at low metal temperatures with controlled amounts of hydrogen yielded castings with excellent properties and required minimum risering. This same effect could not be obtained in heads cast in the semi-permanent mold process, due to segregation of hydrogen caused by the metal molds. Hot isostatic pressing (HIPping) was required to produce the optimum properties, and sand castings with controlled hydrogen HIPped very well.