Highly automated process, optimized using new simulation technique, produces improved ring material
Southfield, Michigan, November 14, 2013. Federal-Mogul Corporation's (NASDAQ:FDML) Powertrain Segment has developed an innovative, highly optimized casting process for piston rings that will provide to engine manufacturers higher quality and stronger, more wear-resistant piston rings. The process uses a highly automated vertical molding process that delivers enhanced material integrity and improved manufacturing process control. Additionally, Federal-Mogul has developed a new casting simulation process that provides more precise data in order to optimize the material flow, pressure and filling of the piston ring casting molds.
"As engine manufacturers continue to pursue strong engine downsizing and more advanced injection strategies to reduce fuel consumption and CO2 emissions, the thermal, mechanical and tribological demands on components around the combustion chamber - particularly piston rings - increases. While engine friction can be reduced through the use of thinner piston rings, a stronger ring material is necessary in order to maintain the proper bending strength," explained Dr. Steffen Hoppe, director of technology, Rings and Liners, Federal-Mogul Powertrain. "To achieve these requirements, we have developed new materials, casting and simulation processes."
New Casting Process
Federal-Mogul's extensive expertise in stack casting over the past 80 years has helped the company achieve consistently high quality within the constraints of a manual or semi-automated casting process. However, with stack casting, horizontal arrangements of multiple molds are stacked above each other in layers, so the design of the runner system is compromised because the pressure and flow velocity of the molten metal varies across the different levels in the stack. The one-piece molds used in the stack casting process also reduce the range of piston ring design options.
To overcome these limitations, Federal-Mogul's new, highly automated, vertical casting process uses a special mold design which provides new opportunities to optimize the design of the blanks and gating systems, improving control of material flow. The new casting form allows the feeding around the complete circumference of the casting, which improves the uniformity of the graphite formation of the grey cast iron significantly. Fully automatic molding and casting, with extensive monitoring and in-process documentation of all relevant parameters ensures more reproducible molten material flow rates and more thorough mold filling, resulting in greater consistency in ring quality.
New Casting Simulation
In order to perfect the vertical casting process, Federal-Mogul also developed an entirely new casting simulation method using high-speed camera technology that overcomes the limitations of conventional finite element (FE) modeling. "FE simulation has one major drawback," explained Hoppe. "No matter how fine a network is selected, the 'macro process' is still simulated. How close the simulation is to reality always depends on how well the simulation parameters are chosen and set."
Called Slow-Motion Casting Simulation (SMCS), the new Federal-Mogul technique provides a much more detailed analysis of the filling of molds, enabling more precise optimization of the complex gating and feeder systems controlling molten material flow. Using SMCS, the flow behavior of the melt at different temperatures and casting speeds can be tracked more effectively, leading to greater understanding and control of pressure fluctuations and the explosive reactions of casting gases.
New Casting Material
The optimized casting process provided the opportunity to simultaneously develop a more highly refined cast steel material. Traditionally, a high strength martensitic grey cast iron containing nodular graphite would be used for diesel engine rings, with good ductility and strength up to around 1200MPa. Federal-Mogul's new cast steel material, GOE70, is characterized by a martensitic matrix structure with embedded chromium carbides and strength of at least 1800MPa. This formulation can be further improved for extremely high wear resistance by adding nitriding, providing a surface hardness of up to 1300 HV.
Piston rings made from GOE70 were subjected to a high number of endurance tests on heavy-duty diesel engines and showed exceptionally low side face wear and high robustness, enabling reduced exhaust gas blow-by and lower oil consumption. Series production of rings made from GOE70 began in 2012, with the first application on a highly loaded heavy-duty engine meeting EU6 emissions standards.
"Through the development of innovative casting, molding and simulation technologies that provide enhanced control of key process parameters, we have achieved improved product quality and increased strength and wear resistance," said Hoppe. "We believe this new ring process technology will further strengthen Federal-Mogul's leading position in the light and commercial vehicle piston ring market."
Federal-Mogul Corporation (NASDAQ:FDML) is a leading global supplier of products and services to the world's manufacturers and servicers of vehicles and equipment in the automotive, light, medium and heavy-duty commercial, marine, rail, aerospace, power generation and industrial markets. The company's products and services enable improved fuel economy, reduced emissions and enhanced vehicle safety.
Federal-Mogul operates two independent business segments, each with a chief executive officer reporting to Federal-Mogul's Board of Directors. Federal-Mogul's Powertrain segment designs and manufactures original equipment powertrain components and systems protection products for automotive, heavy-duty, industrial and transport applications. Federal-Mogul's Vehicle Components segment sells and distributes a broad portfolio of products through more than 20 of the world's most recognized brands in the global vehicle aftermarket, while also serving original equipment vehicle manufacturers with products including braking, chassis, wipers and other vehicle components. The company's aftermarket brands include ANCO® wiper blades; Champion® spark plugs, wipers and filters; AE®, Fel-Pro®, FP Diesel® Goetze®, Glyco®, Nüral®, Payen® and Sealed Power® engine products; MOOG® steering and suspension parts; and Ferodo® and Wagner® brake products.
Federal-Mogul was founded in Detroit in 1899. The company employs 44,500 people in 34 countries, and its worldwide headquarters is in Southfield, Michigan, United States. For more information, please visit www.federalmogul.com.
Federal-Mogul Corporate Communications