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Material data sheet

Steel grade

Last revised: Tue, 07 Feb 2023 13:36:23 GMT

General Information

Ovako 825 is a through hardening bearing steel that is mainly used for medium sized bearing rings, but it can also be used for machine components that require high tensile strength, hardness and toughness.

  • Through hardenability corresponding to a ring with approximately 30mm wall thickness (≈Ø50mm bar), quenched in oil
  • Suitable for martensitic or banitic hardening
  • Good machinability in soft annealed condition
  • Good dimensional stability 

825B - Standard BQ variant

825T - BQ variant with a controlled low sulphur content to minimize the number of sulphide inclusions. Reduced carbon content and tighter chemical composition ranges  

825Q - Isotropic properties (IQ) and better fatigue strength due to higher cleanliness levels, and a finer size and distribution of non-metallic inclusions  


IQ-Steel® is an isotropic quality ultra clean steel optimized for high fatigue strength under multi axial loading.

BQ-Steel® is a bearing quality clean steel optimized for fatigue strength and is also ideal for new design solutions outside the bearing industry.

Similar designations

ASTM A485 grade B6, 1.3536



Tempering response

Steel cleanliness

Micro inclusions - Ovako 825B   Macro inclusions - 825B
Applied standard ASTM E45 Applied standard

ISO 3763

(Blue fracture)

Sampling ASTM A295 Sampling Statistical testing on billets.


average limits

A B C D Limits < 2,5 mm/dm2
Th He Th He Th He Th He
2,0 1,5 0,8 0,1 0 0 0,5 0,3
Micro inclusions - IQ   Macro inclusions - IQ
Applied standard DIN 50602  K1 Applied standard

ISO 3763

(Blue fracture)

10 M Hz UST

(Ovako internal procedure)

Sampling Six random samples from final product dimension Sampling Statistical testing on billets

The limit is dimension dependent. The average rating of six samples should not exceed the

limits given in the graph

Limits < 1 mm/dm2

< 5 defects/dm3 

> 0,2 mm FBH 


Other properties (typical values)

Youngs module (GPa)Poisson´s ratio (-)Shear module (GPa)Density (kg/m3)
210 0.3 80 7800
 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)
 12  460 - 480  40 - 45  0.20 - 0.25

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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.