Bearing Steels - BG42 - AMS5749

BG42 - AMS5749

BG42 is a double vacuum melted martensitic stainless steel designed for aerospace structural components and high performance bearings. The steel is vacuum induction melted (VIM) and vacuum arc remelted (VAR). This provides a high cleanliness level necessary for fatigue-critical applications. BG42 has proven to be an excellent knife steel when produced in sheet form. It offers excellent wear and corrosion resistance. The molybdenum enhances the corrosion resistance provided by the high chromium content.

Chemical Composition

Spec: AMS 5749

Chemical Element % Present
Carbon (C) 1.15 max
Manganese (Mn) 0.0 - 0.50
Silicon (Si) 0.0 - 0.30
Molybdenum (Mo) 0.0 - 4.00
Vanadium (V) 0.0 - 1.20
Chromium (Cr) Balance




Mechanical PropertyValue
Hardness Rockwell C 59.0-62.5 HRC

Supplied Forms

  • Bar
  • Sheet


Download PDF Version

Datasheet Search

Last Datasheet Revision

18 July 2019


This Data is indicative only and as such is not to be relied upon in place of the full specification. In particular, mechanical property requirements vary widely with temper, product and product dimensions. All information is based on our present knowledge and is given in good faith. No liability will be accepted by the Company in respect of any action taken by any third party in reliance thereon.

Please note that the 'Datasheet Update' date shown above is no guarantee of accuracy or whether the datasheet is up to date.

The information provided in this datasheet has been drawn from various recognised sources, including EN Standards, recognised industry references (printed & online) and manufacturers’ data. No guarantee is given that the information is from the latest issue of those sources or about the accuracy of those sources.

Material supplied by the Company may vary significantly from this data, but will conform to all relevant and applicable standards.

As the products detailed may be used for a wide variety of purposes and as the Company has no control over their use; the Company specifically excludes all conditions or warranties expressed or implied by statute or otherwise as to dimensions, properties and/or fitness for any particular purpose, whether expressed or implied.

Advice given by the Company to any third party is given for that party’s assistance only and without liability on the part of the Company. All transactions are subject to the Company’s current Conditions of Sale. The extent of the Company’s liabilities to any customer is clearly set out in those Conditions; a copy of which is available on request.