Stainless Steel Sheets

General Properties

Alloy 17-4PH (UNS S17400), Type 630, is a chromium-nickel-copper precipitation-hardening martensitic stainless steel with an addition of niobium. 17-4PH combines high strength and hardness with good corrosion resistance.

The alloy is furnished in the solution annealed condition (Condition A). It should not be used at temperatures above 572 DegreeF (300 DegreeC) or for cryogenic service. Optimal mechanical properties can be obtained by subjecting the alloy to age hardening heat treatments. Heat treatment in the 900 DegreeF (482 DegreeC) range produces the highest strength.

The corrosion resistance of Alloy 17-4PH is comparable to 304 stainless steel in most environments, and is generally superior to the 400 series stainless steels. It is used in applications where the combination of moderate corrosion resistance and unusually high strength are required.

Alloy 17-4PH can be easily welded and processed by standard shop fabrication practices. It is magnetic.

Applications

• Aerospace - structural and parts
• Biomedical - hand tools
• Chemical Processing
• Food Process Equipment
• Gate Valves
• Mechanical Components
• Nuclear Waste Processing and Storage
• Oil and Gas Production - foils, helicopter deck platforms, etc.
• Pulp and Paper - paper mill
  equipment

Standards ASTM........A 693
ASME........SA 693
AMS..........5604

Corrosion Resistance

The corrosion resistance of Alloy 17-4PH is comparable to 304 stainless steel in most environments, and is generally superior to the 400 series stainless steels. It is used in applications where the combination of moderate corrosion resistance and unusually high strength are required. Alloy 17-4PH has corrosion resistance comparable to 304L in some chemical, dairy, food, paper and petroleum applications.

Alloy 17-4PH in the solution-annealed condition (Condition A) should not generally be put in service. The alloy is subject to brittle fractures and more sensitive to chloride stress corrosion cracking than the aged material.

If risks of chloride stress corrosion cracking are present the higher aging temperatures should be selected over 1022 DegreeF (550 DegreeC), preferably 1094 DegreeF (590 DegreeC). 1022 DegreeF (550 DegreeC) is the recommended tempering temperature in chloride service. 1094 DegreeF (590 DegreeC) is preferred in H2S media.

Alloy 17-4PH is subject to crevice corrosion and pitting attack when exposed to stagnant seawater for a duration of time.

Chemical Analysis

Weight % (all values are maximum unless a range is otherwise indicated)