Papers by Author: John L. Jorstad

Abstract: This paper considers the industrial viability of SSM in comparison to other casting processes and the products each process is best able to produce; in such a perspective, SSM has much to offer especially in terms of cost effectiveness for thinner-walled and higher-integrity cast product lines. The ultimate success of SSM will rely on lessons learned from all past thixocacting and rheoocasting developments and experiences. Proposed is new thinking with regard to adaptation of rheocasting to conventional casting equipment; changing the semi-solid processing paramigm is key to ultimate SSM competitiveness and to opening vast new markets for for semi-solid cast products.

Abstract: Aluminium Rheinfelden has improved the competitiveness of semi solid processing by developing a casting process & alloy combination that is capable of ultra thin, ultra light parts having attractive engineering properties without need for full heat treatment. The THINCASTTM rheocasting process, together with Rheinfeldens Magsimal-59 alloy has been demonstrated capable of producing moderate sized castings with only 1-2 mm wall sections, thus providing a 30-50% reduction in traditional-process part weight. THINCASTTM can be adapted to a variety of die casting machines and will enable competitively improving the quality of conventional high pressure die castings as well as creating entirely new applications.

Abstract: The objective of this presentation is to show and explain why semisolid slurries can fill thin sections at seemingly unlimited flow velocity; the suitability of SSM parts with very thin sections is a characteristic of the process that is often overlooked by the industry. This fact provides a unique opportunity for new advanced applications of the process, not possible by any of the existing metal-mold casting methods.

Abstract: Semi solid metal processing has numerous technical and economic advantages, such as viscous, non-turbulent flow (thus no air entrapment during casting), ability to fill ultra-thin sections (thus reduced part weight), little solidification shrinkage in the die (thus little or no porosity), minimum heat imparted to tooling (thus long tool life) and good response to T-5 aging (thus reduced heat treating costs). Still, SSM has never achieved a prominent position in the field of light metals casting Why Perhaps the reason was largely the down economy of recent years and SSM will yet emerge with the prominence once expected of it.

Abstract: By 2050 the world population will reach over nine billion and “flattening of the world” will be an understatement. We anticipate burgeoning needs regarding energy resources, transportation, housing, food distribution/packaging for the masses, recycling, and health care/ health care delivery, not to mention climate change and environmental issues. World population is increasing at an average rate of 1.4%, and in contrast world energy consumption is increasing at an average rate of 1.7%. Such an imbalance is not sustainable. From a societal perspective, engineers have played a major role to enhance the quality of life in our world. Sustainable development in the 21st Century is perhaps the most critical issue we face. This keynote will address the solutions that light metals technologies bring to the table to meet these challenges. The opportunities for processing and component manufacture to address these challenges will be reviewed and discussed.

Abstract: The globular microstructure required for semi solid metal (SSM) processing was initially developed by agitating melt to fragment dendrites during alpha-phase solidification. More recently, it was learned that a suitable structure was also achievable through copious nucleation of fine grains at a temperature close to the liquidus coupled with controlled cooling to prevent dendrite growth; a technique that can be applied to liquid casting processes but that is especially useful for semi solid Rheocasting (the slurry version of SSM). Rheocasting experiments were conducted to test the interactions of microstructure developed by the copious nucleation route, fractions of solid up to 0.5 during casting and slurry flow velocities up to 5 meters per second. Their combined effects on casting defects and tensile properties will be presented and discussed.