Alloy steels are iron-carbon steels enhanced with elements like chromium, nickel, molybdenum, and manganese (typically 1–50% by weight) to significantly improve strength, hardness, toughness, wear resistance, and corrosion resistance.
Alloy steel can be further classified based on the total content of alloying elements
Low alloy steel ：with a total alloying element content of no more than 5%.
Medium alloy steel ：with a total alloying element content of 5% to 10%.
High alloy steel :with a total alloying element content of more than 10%.
In addition, according to the types of major alloying elements contained in steel, it can also be classified as manganese steel, chromium steel, chromium-nickel steel, chromium-manganese-titanium steel, etc.
Alloy steels variously improve strength, hardness, toughness, wear resistance, corrosion resistance, hardenability, and hot hardness. To achieve these improved properties the metal may require specific heat treating, combined with strict cooling protocols
Related ：
Fastener Hardness
