Custom 630 (17-4 PH)

UNS #S17400

Custom 630 (17Cr-4Ni) is a martensitic precipitation/age-hardening stainless steel offering high strength and hardness along with excellent corrosion resistance. It has good fabricating characteristics and can be age hardened by a single-step, low temperature treatment. Available in a Project 70®+ modified version for improved machinability for applications that call for extensive machining.

Type Analysis

  • Carbon (Maximum) 0.07
  • Phosphorus (Maximum) 0.04
  • Silicon (Maximum) 1
  • Nickel (Nominal) 3.00-5.00
  • Manganese (Maximum) 1
  • Sulfur (Maximum) 0.03
  • Chromium (Nominal) 15.00-17.50
  • Iron (Nominal) Balance
  • Copper (Nominal) 3.00-5.00
  • Columbium + Tantalum0.15-0.45


Oil field valve parts, chemical process equipment, aircraft fittings, fasteners, pump shafts, nuclear reactor components, gears, paper mill equipment, missile fittings, and jet engine parts.

Applicable Specifications

  • AMS 5643
  • ASTM A564
  • ASTM A705
  • ASME SA564
  • ASTM A693 (Strip)






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