Steel alloy, article of manufacture and method

A steel alloy consisting of:

• 0.65-0.9 mass % carbon;
• 0.1-0.5 mass % vanadium and 0.01-0.1 mass % niobium;
• 0.5-1.2 mass % manganese;
• 0.1-0.6 mass % silicon;
• 0-0.5 mass % molybdenum;
• 0-0.5 mass % chromium;
• 0-1 mass % nickel;
• 0-0.4 mass % copper;
• 0-0.05 mass % aluminum;
• a balance being iron and impurities.

A method of making an article of manufacture, comprising

• providing a semi-finished product comprising a steel alloy consisting of
• 0.65-0.9 mass % carbon,
• 0.1-0.5 mass % vanadium and 0.01-0.1 mass % niobium,
• 0.5-1.2 mass % manganese,
• 0.1-0.6 mass % silicon,
• 0-0.5 mass % molybdenum,
• 0-0.5 mass % chromium,
• 0-1 mass % nickel,
• 0-0.4 mass % copper,
• 0-0.05 mass % aluminum,
• a balance being iron and impurities,
• in a first heat treatment, heat treating the semi-finished product at 550° C.-725° C. for at least 4 hours, immediately followed by a first cooling,
• forming or cold-forming the semi-finished product to provide the article of manufacture,
• in a second heat treatment following the first heat treatment, heat treating the article of manufacture at 730° C.-1150° C., immediately followed by a second cooling more rapid than the first cooling, wherein the article of manufacture is hardened to a Rockwell hardness of more than 57 HRC during the second heat treatment.