18NiCrMo14-6 is a case hardening steel with high toughness used for bearing and transmission components. There are two different versions of the grade with high cleanliness requirements. The high hardenability ensures a through hardenability of large sections.
255G - Bearing quality (BQ) variant with low sulphur content and high cleanliness demands
255Q - Isotropic quality (IQ) with isotropic properties and improved fatigue strength due to higher cleanliness levels, and a finer size and distribution of non-metallic inclusions
BQ-steel® is a bearing quality clean steel optimized for fatigue strength and is also ideal for new design solutions outside the bearing industry.
IQ-Steel® is an isotropic quality ultra clean steel optimized for high fatigue strength under multi axial loading.
Other properties (typical values)
|Youngs module (GPa)||Poisson´s ratio (-)||Shear module (GPa)||Density (kg/m3)|
| Average CTE 20-300°C (µm/m°K)|| Specific heat capacity 50/100°C (J/kg°K)|| Thermal conductivity Ambient temperature (W/m°K)|| Electrical resistivityAmbient temperature (µΩm)|
|| 460 - 480
|| 40 - 45
|| 0.20 - 0.25
The information in this document is for illustrative purposes only. The data and examples are only general recommendations and not a warranty or a guarantee. The suitability of a product for a specific application can be confirmed only by Ovako once given the actual conditions.The purchaser of an Ovako product has the responsibility to ascertain and control the applicability of the products before using them. Continuous development may necessitate changes in technical data without notice. This document is only valid for Ovako material. Other material, covering the same international specifications, does not necessarily comply with the properties presented in this document.