AISI 4820H Alloy Steel Chemical Composition & Properties, Grades, Table and Pdf

AISI 4820H alloy steel is a multipurpose material known for its strong characteristics which among others makes it suitable for various machine and plant building field. Its chemical formula is principally made from carbon, manganese, chromium, molybdenum, and other alloying metals that guarantee metallic features. This grade offers good resistance to wear, overload fatigue, and toughness, all qualities, which are necessary for the components operating in highly fatigued and heavy-loaded conditions. The AISI 4820H advantage of being very balanced allows for great hardenability and machinability, which in turn, decreases the difficulty of forming and shaping. The engineers and manufacturers often use tables and chart or PDF documents that thoroughly present grades, features, and attributes in their applications which need a particular performance.

AISI 4820H Alloy Steel Chemical Composition And Grade Table

The alloy steel no longer contains trace amounts of carbon and features nickel as a major additive which is a synonym of its excellent hardenability and toughness. The chemical composition of ferrous alloys usually includes carbon, manganese, chromium, nickel, molybdenum and silicon as the elements. It has a tiny portion of carbon only 0.18%, as well as an amount of manganese 0.60-0.90%, chromium 0.70-0.90%, and nickel 1.45-1.80%. Due to these qualities, the alloy can as good mechanical properties, which makes it suitable for different applications. AISI 4820H is widely adopted in the manufacturers of teeth, shafts, as well as other parts of high stress where toughness, wear resistance and durability are primary requirements.

AISI 4820H Alloy Steel Composition Table
Elements Iron, Fe Nickel, Ni Manganese, Mn Molybdenum, Mo Carbon, C Silicon, Si Sulfur, S Phosphorous, P
Min (%) 94.495 3.2 0.4 0.2 0.17 0.15 - -
Max (%) 95.88 3.8 0.8 0.3 0.23 0.3 ≤ 0.0400 ≤ 0.0350

Advantages and Disadvantages of AISI 4820H Alloy Steel


  • High Strength: Offers high mechanical performance suitable for specific strenuous applications.

  • Good Toughness: Maintains high toughness even after heat treatment.

  • Wear Resistance: Exhibits excellent wear resistance when hardened.

  • Machinability: More easily machinable compared to other alloy steels.


  • Cost: Higher cost compared to basic carbon steels.

  • Complex Heat Treatment: Requires stringent heat treatment procedures.

  • Weldability: Moderately weldable, may require preheat and post-weld heat treatment.

  • Susceptibility to Decarburization: Sensitive to surface decarburization during heat treatment.

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