Ovako 355B is a quench and tempering steel with high toughness and cleanliness. Oil hardening steel for quench and tempering. Used for large axles, machine componenets etc. that require high tensile strength and high toughness. The grade is inside the SAE 4340 specification but is slightly enhanced with Vanadium for improved tempering resistance. The grade has a low controlled sulphur content to ensure machinability yet with a high sulphidic cleanliness. Oxygen content is kept low for high oxidic cleanliness. The steel is of Bearing Quality cleanliness (BQ).
Can be flame or induction hardened
Through hardenability corresponding to a bar with approx. Ø100mm (oil quenching)
Available as hot rolled bars, tubes and rings
Delivered in as-rolled, soft annealed, normalized or quench and tempered condition
(Bearing Quality) is a bearing quality clean steel optimized for fatigue strength by a strict control of steel cleanliness. BQ-steel is also ideal for new design solutions in a wide array of demanding applications outside the bearing industry that require longer performance and higher loads. The BQ-steel offer is the result of the Ovako clean steel program. Purity of production means that the material has significantly smaller inclusions compared to conventional steel and, as a result, the fatigue strength of the steel is increased dramatically. Use of the material allows components to be manufactured in smaller sizes. The BQ-steel has for decades been the problem-solver.
* Designation followed by "*" is not an official EN standard grade but named according to the rules in EN 10027.