AQ 8620 steel is a low-alloy steel that is commonly used in applications requiring high strength and toughness, as well as good wear resistance. Here are some key characteristics and applications of AQ 8620 steel:

Characteristics of AQ 8620 Steel:

  1. Composition:

    • AQ 8620 is composed primarily of iron, with the addition of elements like nickel, chromium, and molybdenum. These elements enhance the steel's hardenability and strength.
    • Typical composition includes:
      • Carbon (C): 0.18-0.23%
      • Manganese (Mn): 0.70-0.90%
      • Chromium (Cr): 0.40-0.60%
      • Nickel (Ni): 0.40-0.70%
      • Molybdenum (Mo): 0.15-0.25%
      • Silicon (Si): 0.15-0.35%

  2. Mechanical Properties:

    • Tensile Strength: Approximately 120-130 ksi (kilopounds per square inch) when heat-treated.
    • Yield Strength: Approximately 60-70 ksi.
    • Elongation: Typically around 10-15% in 2 inches.
    • Hardness: Can achieve high hardness levels (Rockwell C 58-62) after appropriate heat treatment processes like carburizing and quenching.

  3. Heat Treatment:

    • AQ 8620 steel is often carburized, which involves adding carbon to the surface layer to improve hardness and wear resistance while maintaining a tough, ductile core.
    • The steel can also be quenched and tempered to achieve a balance between hardness and toughness.

  4. Machinability:

    • AQ 8620 has good machinability, allowing it to be readily machined into complex shapes and components.

  5. Weldability:

    • This steel can be welded, but preheating and post-weld heat treatment may be necessary to avoid cracking and ensure the integrity of the weld.

Applications of AQ 8620 Steel:

  1. Gears and Pinions:

    • Commonly used in the manufacture of gears and pinions due to its excellent wear resistance and toughness.

  2. Automotive Components:

    • Utilized in various automotive parts such as transmission components, shafts, and crankshafts.

  3. Heavy Equipment:

    • Suitable for components in heavy machinery and equipment that require high strength and durability.

  4. Tooling and Fixtures:

    • Used in the production of tooling and fixtures that need to withstand high stress and wear.

  5. Aerospace:

    • Employed in certain aerospace applications where high strength and wear resistance are critical.

Summary:

AQ 8620 steel is a versatile low-alloy steel known for its excellent hardenability, strength, and toughness. Its ability to be heat-treated for enhanced surface hardness while maintaining a ductile core makes it ideal for high-wear applications such as gears and automotive components. With good machinability and weldability, AQ 8620 is a popular choice in various industries requiring reliable, high-performance steel.