Precipitation Hardening (PH) stainless steels are classified as martensitic or semi-austenitic.
They develop their high strength and hardness through a variety of heat treatments resulting in a very
high strength-to-weight ratio. Semi-austenitic grades are 17-7 PH and PH 15-7 Mo.
They are austenitic in the annealed state, and martensitic in the hardened condition.
Martensitic grades include 17-4 PH and 15-5 PH.
The PH grades achieve high tensile properties in heat treated conditions.
Applications for PH steels include aerospace components, flat springs, and retaining rings.
17-4 PH STAINLESS STEEL is the most widely used of all the precipitation-hardening stainless steels.
Its valuable combination of properties gives designers opportunities to add reliability to their products
while simplifying fabrication and often reducing costs. This valuable alloy is widely used in the aerospace, chemical,
petrochemical, food processing, paper and general metalworking industries.
17-4 PH Stainless Steel is a martensitic precipitationhardening steel that provides an outstanding
combination of high strength, corrosion resistance, good mechanical properties at temperatures
up to 600 °F (316 °C), toughness in both base metal and welds, and short-time,
low-temperature heat treatments that minimize warpage and scaling.
|Chemical composition %
C 0.07 max, Cr 15.00~17.50,
Ni 3.00~5.00, Cu 3.00~5.00, Nb 0.15~0.45
17-4 PH Stainless Steel is produced in sheet and strip.
In these forms, the alloy is supplied in Condition A, ready for fabrication and subsequent hardening by the user.
Since the material transforms to martensite on cooling to room temperature, flatness requirements
should be considered and discussed as part of the order.
The following specifications are listed without revision indications.
Contact ASTM Headquarters for latest ASTM revision. For AMS revision,
contact AMS Division of SAE.
AMS 5604 Sheet, Strip and Plate
ASTM A693 Plate, Sheet and Strip
(Listed as Grade 630 - UNS S17400)
Contact Person: Mr. Paul