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Technical Standards are essential for the expanded use of any engineering material. The Society of Automotive Engineers (SAE) Iron and Steel Castings Committee has been reworking existing, (and issuing new), standards for automotive iron and steel castings. This paper will review the status of the SAE standards for Ductile Iron, Austempered Ductile Iron (ADI), Compacted Graphite Iron (CGI) and high Silicon-Molybdenum (Si-Mo) Ductile Iron, Gray Iron and Steel Castings. The SAE Standards, (and draft standards), will be critically compared to those for ASTM and ISO. Salient differences in the standards will be discussed and implications to design engineers will be addressed. Comparisons to other, competitive materials (and their standards) will be made.

The Carbo-Austempering™ process is a high performance steel heat treatment that combines a high carbon bainitic case with either a bainitic or tempered Martensite core to produce a component with an exceptional combination of strength and toughness. This paper will review the Carbo-Austempering™ process and its commercial applications. The properties of Carbo-Austempered™ steel along with the benefits and limitations of the process will also be discussed.

In the increasingly competitive trucking industry, operators are continually seeking ways to haul higher volume and/or heavier loads to maintain profitability. Cross-continent shipments in Australia offer unique performance challenges to the box, frame, axles and suspension. Independent suspensions on large over-the-road box trailers can allow flat floors and increased cargo space. This paper chronicles the development of a unique suspension system that utilizes a complex ADI casting to survive the rigors of the Australian Outback. The suspension uses a short “stub” axle mounted and suspended at each wheel thus eliminating the need for a full axle running under the box and frame. This “axle-less” suspension allows the trailer box to have a flat floor and an additional 20 cubic meters of cargo space. The ADI suspension successfully replaced an earlier system constructed of steel weldments that failed in service.

Austempered cast irons have a unique microstructure (ausferrite) that provides for excellent wear properties. This paper will examine the available data in the literature on wear in several modes: abrasive wear, adhesive wear (frictional or sliding and rolling), and erosive wear. Additional wear data, including that from competitive materials as well as from private communications, will be presented along with examples of applications of austempered ductile cast irons where wear properties are of concern

Austempered Ductile Iron was first commercially applied in 1972. By the mid 1970's it had found its way into Chinese Military trucks and into commercial truck applications in Europe. By 1978, austempered ductile iron had been applied to light cars and trucks in the US. Today, it is estimated that over 50,000 tons per year of austempered ductile iron components are installed in cars and trucks world-wide. That production appears to be growing at a rate of exceeding 10% per year. As a family of materials, austempered ductile iron capably addresses the issues of weight, strength, stiffness, noise, cost and recyclability. From the first differential gear sets installed by General Motors in 1978, to light-weight truck-trailer wheel hubs, to high performance automobile suspensions, austempered ductile iron has found itself in many unique applications. This paper will review those applications, the reason(s) for the conversions, and the performance of those components.

The Austempering process is a high performance heat treatment that, when applied to ferrous materials, produces components that, in many cases, have properties superior to those processed by conventional means. The Austempering processes include: Austempered Ductile Iron Austempered Gray Iron Austempered Steels and Powdered Metals Carbo-Austempered™ Steels Austempered Ductile Iron (ADI) has an exceptionally high strength-to-weight ratio with good fatigue strength and fracture toughness. In fact, with strength three times greater than that of aluminum with only two and a half times the density, ADI can replace aluminum at equal weight for a substantial cost savings. Austempered Gray Iron (AGI) has an excellent combination of noise damping, wear resistance and thermal conductivity. It has received a great deal of attention as diesel engine manufacturers increase cylinder pressures to meet ever more stringent exhaust requirements.