HP 9-4-20

UNS #K91472

HP 9-4-20 VAC-ARC steel is a low alloy, high-strength steel with a high nickel and cobalt content to promote toughness. The alloy has been designed to have high hardenability, good weldability, and excellent fracture toughness. It is typically used in the 200/205,000 psi (1374/1408 MPa) yield strength range. HP 9-4-20 steel is produced by the consumable electrode vacuum arc remelting process to provide optimum cleanliness and preferred ingot structure.

Type Analysis

  • Carbon (Nominal) 0.2
  • Phosphorus (Maximum) 0.01
  • Silicon (Nominal) 0.1
  • Nickel (Nominal) 9
  • Manganese (Nominal) 0.3
  • Chromium (Nominal) 0.75
  • Cobalt (Nominal) 4.5
  • Molybdenum (Nominal) 1
  • Iron (Nominal) Balance
  • Vanadium (Nominal) 0.09


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Applicable Specifications

  • AMS 6525
  • AMS 6468
  • AMS 6523



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