Project Manager, Ovako Steel AB, Göteborg,
Manager, Materials Technology, Ovako Steel AB, Hofors,
Pages: 12 Published: Jan 2002
Environmental issues are becoming increasingly important as the costs of waste disposal increase and global climate effects of petroleum product usage become more evident. A major problem in the manufacturing of bearing components today is the distortion generated in the heat treatment quenching operation. The quenching is difficult to control and is a polluting fire and health risk due to the quenching media used. The hardening distortion causes excessive grinding, and large efforts have been made to reduce distortion and the excessive grinding costs caused by this. Major efforts have been made to develop gas quenching, but as the standard steels used for component manufacturing today have very limited hardenability, only a minor share of the component range can be effectively gas quenched.
By utilizing modern tools for material development, a family of low-alloyed steel has been designed which combine environmental friendliness, minimum hardening distortion and improved product performance for industrial components. The steels also have been designed in such a way that standard, high volume production routes can be utilized, and -with the advances in hard machining — in many cases can be used to design new and very cost efficient ways of component production with a minimal environmental impact.
This paper presents a concept where components can be martensitically hardened in a simple air cooling, even directly on cooling from a hot forming operation. These steels significantly reduce hardening distortion, improve working environment and are environmentally friendly. They also offer the potential to change component production routes drastically and as well provide high performance components for large volume production.
bearing steel, heat treatment, quenching, distortion, environment, hard machining
Paper ID: STP10847S