Laser-Processed Piston Rings from Federal-Mogul Powertrain Could Offer Reduced Friction and Longer Time Between Engine Overhauls
Innovative coating process could enable large bore 2-stroke and 4-stroke engines to meet the challenges of increasing loads and temperatures
Southfield, Mich. August 30, 2018… Federal-Mogul Powertrain is developing laser processes to give future piston rings for large bore engines (LBE) unprecedented wear resistance. The techniques offer an environmentally friendly, long-term alternative to galvanic coatings and are the latest step in the company’s continuous research into new surface treatments that will meet the challenges of future engine and fuel developments in the marine and industrial sectors. Federal-Mogul Powertrain is showcasing its range of piston rings and other LBE products at the 2018 SMM in Hamburg, Germany (4–7 September, Booth 205/Hall A3), the Shipbuilding, Machinery and Marine technology trade show.
Trends to reduce operating costs and emissions are driving future engine designs, both 2-stroke and 4-stroke, and will result in heavier loads and increased temperatures for piston rings. Operators are requiring reduced friction, fuel and oil consumption, as well as increased time between overhauls, with ring lifetimes of 24,000 hours or more expected.
The worldwide introduction of low-sulphur fuels from 2020 and the increased market share of gas and dual-fuel engines will present additional tribological challenges for piston rings and cylinder liners. Meeting these challenges requires ring materials with high dimensional stability as well as coatings with low coefficients of friction, high scuff resistance and low piston ring and cylinder wear rates.
“We are constantly developing advanced new technologies, in order to stay ahead of emerging trends in the global marine market,” explained Peter Arndt, Director and General Manager for Large Bore Engine Rings, Federal-Mogul Powertrain. “Laser processes offer exciting possibilities for surface enhancement and can be applied to a wide range of base materials including both grey iron and SG iron.”
Federal-Mogul Powertrain is developing a number of laser processes, including laser structuring, laser re-melting, laser alloying and laser deposition welding. Laser deposition welding is already widely used as a coating process to replace hard chrome layers, using Ni- and Co-based alloys with dispersed hard materials. However, meeting future requirements for piston ring running faces will require new coating materials. Promising candidates are Fe- and Ni-based materials alloyed with hard phases and carbide forming elements.
The surface properties of grey cast iron materials can be drastically altered by laser re-melting to significantly increase abrasive wear resistance. A high-energy laser melts the iron, which is spontaneously quenched by movement of the laser focus to produce a white-solidified, ledeburitic material structure containing Fe3C with a hardness of approximately 800 HV.
Size and distribution of the Fe3C hard phases can be flexibly adjusted by the laser energy input. Both laser re-melting and laser deposition welding produce a metallurgical bond between the base material and the functional coating material.
Building on past experience
Federal-Mogul Powertrain has previously developed a number of highly successful innovative surface treatments for the piston rings of large bore engines, with laser-based processes set to become the latest addition to the range.
Galvanic hard chrome coatings such as CKS®, containing up to 10% embedded 2-5 µm aluminum oxide particles, significantly improve wear and scuff resistance on ring running surfaces and side faces. Higher hard phase contents (up to 60% by volume) can be produced by thermal spraying techniques.
Even greater wear resistance than CKS is achieved by diamond-reinforced hard chrome coatings (GDC®, Goetze Diamond Coating). Federal-Mogul Powertrain’s novel GDC60 coatings show extremely low friction coefficients under engine conditions, with greatly reduced running surface wear and significantly lower cylinder wear.
PVD (Physical Vapor Deposition) hard coatings of CrN or CrON provide high wear resistance and very high scuff resistance under high thermal loads. Coating thickness is limited to less than 50 µm by the application process, whereas the new laser re-melting method can achieve up to 1 mm, extending the service life.
“Initial engine tests of large bore rings with laser re-melted side faces so far show extremely positive results,” said Arndt. “This solution for surface reinforcement of the side faces, on one or both sides, can be combined with all common existing running face coatings to provide high load resistance with very long service life.”
Pre-series production using laser re-melting of piston ring side faces is scheduled for the end of 2018. Material development for laser deposition welding on the piston ring running surface is currently underway, with first engine tests expected in early 2019.
About Federal-Mogul
Federal-Mogul LLC 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 divisions, each with a chief executive officer reporting to Federal-Mogul’s Board of Directors.
Federal-Mogul Powertrain designs and manufactures original equipment powertrain components and systems protection products for automotive, heavy-duty, industrial and transport applications.
Federal-Mogul Motorparts 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, wipers and a range of chassis components. The company’s aftermarket brands include ANCO® wipers; Beck/Arnley® premium OE quality parts and fluids; BERU®* ignition systems; Champion® lighting, spark plugs, wipers and filters; Interfil® filters; AE®, Fel-Pro®, FP Diesel®, Goetze®, Glyco®, National®, Nüral®, Payen®, Sealed Power® and Speed-Pro® engine products; MOOG® chassis components; and Abex®, Ferodo®, Jurid® and Wagner® brake products and lighting.
Federal-Mogul was founded in Detroit in 1899 and maintains its worldwide headquarters in Southfield, Michigan. The company employs nearly 55,000 in 24 countries. For more information, please visit www.federalmogul.com.
*BERU is a registered trademark of BorgWarner
CONTACT:
Ursula HellsternFederal-Mogul Powertrain Communications+49 (611) 201 9190ursula.hellstern@federalmogul.com