USA: Steel Will Continue as Material of Choice in Powertrain and Chassis Applications, Reports American Iron and Steel Institute
The use of steel bar stock in automotive powertrain and chassis applications will grow by at least six percent over the next 10 years because the material has the potential to improve performance, reduce weight and save cost, according to a recent study by the American Iron and Steel Institute, (AISI).
The study, "State of the Industry on Steel Bars and Rods in Automotive Applications," identifies opportunities for mass and cost savings along with a promising forecast for increasing the advance use of steel in powertrain and suspension systems. Components examined by the study include connecting rods, crankshafts, valves, transmission gear sets, drive shafts, CV joints, rack and pinion steering systems, coil springs, torsion bars, bearings and fasteners.
The report also discusses challenges steel faces if it is to achieve the growth rate the study predicts. Among those challenges is the need for developing new steels and coatings to meet tougher durability requirements, as well as furthering advancements in corrosion protection. As engines, transmissions and other systems continue to become more compact and powerful, the corresponding decrease in component size is impacting requirements for wear resistance, durability and performance, which steel is uniquely suited to deliver.
Engines are prime targets for improving performance and boosting efficiency through the use of steel connecting rods, crankshafts and valves. Although U.S. vehicle makers historically have favored cast iron crankshafts primarily for cost reasons, their European counterparts have long used drop- forged, steel crankshafts because of their lower mass, greater stiffness and better performance in smaller, higher revving engines. By using lighter weight drop-forged steel crankshafts, vehicle makers correspondingly can reduce mass in other major components such as flywheels and clutches, which will further reduce weight, boost fuel economy and improve performance. As vehicle makers around the world continue to rationalize the number of engines they offer globally, there is an excellent likelihood that steel crankshafts will gain in popularity, even among U.S. makers.
Steel engine valves, whether standard design or sodium-filled for additional cooling, ought to maintain their preeminence well into the future, the study predicts, because of their ability to dissipate heat and withstand high loads. Additionally, the study forecasts that the number of valves per cylinder will increase, as vehicle makers strive to improve the "breathing" efficiency of their engines. These factors should contribute to continued growth for steel in these applications.
As is the case with engines, transmission development seeks to reduce package size and mass, while improving power and/or torque output. To further improve efficiency, performance and fuel economy, vehicle makers are adding additional forward gears. Steel gear sets provide the strength, durability, performance and low cost engineers are looking for to design and build the next generation transmissions that will be smaller in size, generate greater loads, and create more risk for wear and tear.
Steel is also the mainstay for driveshaft components, and the study predicts it will remain so for the foreseeable future. While engineers have tested numerous variations and alternative materials to manufacture lighter driveshafts, difficulties in joining tube ends and substantial cost penalties limit their viability for use in production vehicles. Steel tube will remain the most cost-effective approach for rear, all-wheel and four-wheel drive systems.
Another steel mainstay is the "rack and pinion" system, composed of a steel rack, ball joints, and steering arm. Providing durability and reliable performance at low cost, steel rack and pinion steering systems are virtually standard, even in racing, where light weight and high performance are paramount concerns.
The study discusses steel's growth potential in these various applications within an approximate ten-year horizon and takes into account the emergence of alternate propulsion systems, such as fuel cells. Because widespread use of fuel cells is at least ten years off, "steel will continue as the material of choice" well into the future because of its superior ability to provide durability and high performance at an affordable cost.
Under the auspices of the American Iron and Steel Institute, the Bar and Rod Market Development Group strives to grow the market for value-added steel bar and rod products. With 13 member companies, the group pursues this goal through two task forces committed to developing innovative solutions to the challenges facing their clients and the steel industry. These task forces are:
* Automotive/Heavy Equipment
Bar and Rod Market Development Group member companies:
Ispat Inland Bar Company
Ispat Sidbec, Inc.
North Star Steel Company
Republic Technologies International
Slater Steels, Inc.
The Timken Company