Environmentally-friendly heat treatment for the automotive industry – from Europe to China

Current developments in the automotive market, for example engine downsizing for greater efficiency, the increasing use of dual-clutch gearboxes, state-of-the-art turbochargers or the start-stop function, strengthen the importance of specialized surface solutions for many components. Today more than ever, the automotive industry has a growing need for cost-efficient and high mechanical load components that are of consistent quality even outside of Europe.    

Oerlikon Metaplas, as part of Oerlikon Metco, meets these demands and expands its global presence for nitriding technologies. The IONIT treatment service is now offered to customers in China. With roughly a half century of heat treatment technology experience Oerlikon Metaplas is the technology leader. The plasma-supported IONIT process, combining plasma nitriding and plasma nitrocarburizing, is environmentally friendly and already used for many automotive components. In China, the international operating automotive industry can benefit from the exact same processes as in Europe.
   
IONIT: Increasing demands for future automobiles
Current and future developments of state-of-the-art engines and gearboxes will increase the need for heat-treated components. The most common applications are automotive gear transmission components, like synchronizing disks and bodies, disk carriers, clutch disks, differential pinion shafts and selector shafts. Gearboxes convert engine speed and torque along the drivetrain, thus putting the available engine performance literally on the road. The latest engine developments, for example, work with more powerful or multiple turbochargers. The goal is to combine the demand for more torque and power, once considered complementary, with reduced fuel consumption and emissions. Due to this reason, a surface solutions partner outside of Europe is required to guarantee the same component quality and reliability.

The growing number of hybrid drives and dual-clutch gearboxes increased the number of installed clutches and disk carriers enormously. An IONIT treatment reduces wear and increases the lifetime of such components.         

Highly stressed automotive components are subject to critical loads, especially on their surfaces and boundary layers. It is necessary to protect these areas against corrosion and wear, like the IONIT process does. At the same time the IONIT process increases hardness, fatigue strength and improves friction and sliding properties of metal components while ensuring dimensional stability. In addition, cost savings are possible through the substitution of expensive materials with less costly choices. For example, significantly cheaper tempering steels may be used instead of stainless steels. An IONIT treatment is applicable for alloyed steels, cast, sintered and specialized materials. It especially meets the requirements for reproducible tolerances and a distortion-free process.

Plasma nitriding and plasma nitro carburizing
Plasma nitriding as a classic thermo chemical surface heat treatment is a long-proven process for many different automotive components. During the heat treatment process nitrogen, and also carbon when the additional nitro carburizing process is used, diffuses under vacuum into the surface of the treated iron substrate. The process operates with low-energy plasma. The nitrogen and carbon absorption is effected by an ionized gas mixture consisting of nitrogen, hydrogen and the addition of a carbon-containing gas. Nitration can thereby be carried out at temperatures well below those needed for other nitriding processes. It is possible to optimize the component strength and toughness regardless of the respective surface hardness and the surface chemistry of the base material.  

The surface layers of these nitrided materials consist of two layers: A white layer forms directly on the surface. It is usually 2 to 20 μm thick, hard and chemical stable. Below this the diffusion zone is generated with a thickness of 0.1 to 0.8 mm.

The environmentally-friendly plasma nitriding offers many benefits compared to traditional nitriding processes like salt bath and gas: plasma Nitriding. It allows for targeted adjustment of coating structure, hardness change in depth and homogeneity of the built surface layers independently of one another. Additionally this process is the most environmentally-friendly solution.

One June 3, 2014, Oerlikon completed the acquisition of all outstanding equity interests of the Metco Division from the Sulzer Group. As a result of the transaction, a global market and technology leader has been created. The new Oerlikon Segment Surface Solutions employs approximately 6,000 people worldwide, operates 110 coating centers and achieves a turnover of more than CHF 1 Bn. For decades both business units Oerlikon Balzers and Oerlikon Metco showed the leading edge in pioneering developments for coating technologies.

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