Stainless, Duplex, Super Duplex

Grade 17-4 PH

UNS S17400 : ASTM A564 Grade 630 (VO1.03)

General scope

17-4 PH is a precipitation hardening martensitic stainless steel, containing Copper. In the solution treated and doubled aged condition it has become the preferred alloy for Stems and Shafts and is used extensively in valve internals. High strength, including good properties up to 315°C (600°F) and excellent corrosion resistance (comparable to 304 austenitic stainless in many environments) makes this alloy extremely versatile.

In addition to limiting the hardness, NACE MR0175 restricts the age hardening cycles that can be applied to the alloy to two of the several available. NACE MR0175 only permits solution treatment, followed by double aging to either the H1150M condition 760°C (1400°F) / 620°C (1150°F) or the DH1150 condition 620°C (1150 °F) / 620°C (1150°F).

ASTM A564 lists several alternative supply conditions.

Until 2003 this alloy was approved by NACE MR0175 for general use. However, it is now restricted to "special components" and restricted well environments.

Chemical composition

C Si Mn P S Cr Ni Mo Cu NbCbTa Fe
Min 15.00 3.00 3.00 0.15 0.00
Max 0.07 1.00 1.00 0.040 0.030 17.50 5.00 5.00 0.45 0.00

Mechanical properties

Condition: Solution Treated and Double Aged (DH1150)

NACE MR0175 limits the supply hardness to 33 HRC max.
U.T.S 125 KSI Min (862 N/mm2)
0.2% Proof Stress 105 KSI Min (724 N/mm2)
Elongation 18 %
Red of Area 50 %
CVN Impacts @ -29°C (-20°F) 40 Joules (30 ft-lbf)
Size range: 1”∅ - 16”∅

Primarily manufactured in:

  • Dubai, UAE
  • Edmonton, Canada
  • Houston, Texas
  • Sheffield, England
  • Singapore
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