Since 1981, semi-solid metal forming (SSM) in commercial use has been a well-established process in the automotive industry for the production of safety-critical aluminium components such as suspension parts, chassis components, fuel rails and brake cylinders. SSM uses material in a semi-solid state compared to most casting processes, which require a liquid metal.

In the classical SSM process, specially-prepared material, supplied in billet form, is reheated into the semi-solid region of the phase diagram through placing the precut billet into an induction-heating coil. The heated billet maintains its shape and can be handled manually or automatically, while the solid- liquid mixture displays good flowability when injected into a die. SSM has been researched in South Africa since 1996, initially at the University of Natal, Durban (UND), through sponsorship by industry, the CSIR and the Aluminium Federation of South Africa (Afsa). This research led to a Department of Arts, Culture, Science and Technology Innovation Fund project awarded to the CSIR, UND and Afsa in 1999 for three years. Under the guidance of Afsa, the Innovation Fund research is aimed at establishing a technical competence base in SSM-related technologies for South African industry, through the investigation of core technologies associated with the classical SSM approach as well as alternative cost-effective solutions for local industry.

The research follows a two-pronged approach, in which the CSIR is investigating and building competence on the industrial application of SSM, while UND is researching the fundamental characteristics of semi-solid material preparation and behaviour.

The CSIR has divided its research into the following categories: billet reheating characterisation, process modelling and simulation using Procast software, physical production of a component on an industrial scale and the development of an alternative method for creating the premium feedstock with globular structure. UND performs fundamental research on the materials characterisation, recycling and diecasting parameters.

During the characterisation of the reheating process, the CSIR used an induction-heating system that was produced locally. Reheating characterisation is well within the international industry norm, which specifies temperature gradients of about 5

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