17-4PH Stainless Steels

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 . It should not be used at temperatures above 572°F (300°C) or for cryogenic service. Optimal mechanical properties can be obtained by subjecting the alloy to age hardening heat treatments. Heat treatment in the 900°F (482°C) 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.

Common Trade Names:

Type 630 ;17-4PH ; 17-4 Stainless Steel ; UNS S17400 ; X5CrNiCuNb16-4

Specifications：

AMS 5604 / AMS 5622 / AMS 5642 / AMS 5643 / AMS 7012 / MIL-S-25043 / ASTM A564 / ASTM A484 / ASME SA484 / ASTM A564 / ASME SA564 / ASTM A693/ ASME SA693

17-4PH Chemical Composition

17-4PH Typical Physical Properties

17-4PH Mechanical Properties

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 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°F (550°C), preferably 1094°F (590°C). 1022°F (550°C) is the recommended tempering temperature in chloride service. 1094°F (590°C) 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.

Heat Resistance

Grade 630 stainless steels have good corrosion resistance in many environments. They exhibit improved resistance against stress corrosion cracking, if aged at 550°C or more. However, grade 630 steels are less resistant to solution treated Condition A, and hence these steels, even with considerable hardness, should not be used in this condition.

Fabrication Data

Heat Treatment

Solution treatment - Grade 630 stainless steels are heated at 1040°C for 0.5 h, then air-cooled to 30°C. Small sections of these grades can be oil quenched.

Hardening - Grade 630 stainless steels are age-hardened at low temperatures to achieve the required mechanical properties. During the process, superficial discoloration occurs followed by shrinkage at 0.10% for condition H1150, and 0.05% for condition H900.

The table below shows the typical mechanical properties of grade 630 steels after solution treatment and age hardening:

Cold Forming

Alloy 17-4PH has limited cold forming properties. Cold forming can only be undertaken on plates in the fully annealed condition. Stress corrosion resistance is enhanced by re-aging at the precipitation hardening temperature after cold working.

Hot Forming

Heat uniformly at 1742 – 2192°F (950 – 1200°C). A full solution anneal, cooling lower than 76°F (25°C) and aging at the required temperature must occur after hot forming. The post forming heat treatment should be a function of the desired mechanical properties.

Machining

Alloy 17-4PH can be machined in both the solution treated and precipitation hardened conditions. Machining characteristics may vary according to the hardness of the metal. High speed tools are acceptable, but carbide tools are preferred. Standard lubrication should be used. Dimensional changes as a result heat treatment should be taken into account if very stringent tolerances are required.

Cutting

Thermal cutting operations such as plasma cutting should be avoided. Mechanical cutting operations such as bandsaw, abrasive waterjet, shearing and machining are preferred.

Welding

Alloy 17-4PH can be readily welded by most standard processes including SMAW, GTAW, PAW and GMAW.

FAQ

Q: What are your company's main products ?
A: Our main products are stainless steel plate/sheet, coil, round/square pipe, bar, nickel alloys, etc.
Q: How do you control quality ?
A: Mill Test Certification is supplied with shipment, Third Party Inspection is available. and we also get ISO,SGS,Alibaba Verified.
Q: What are the advantages of your company ?
A: We have many professionals, technical personnel, more competitive prices and best after-dales service than other stainless steel companies.
Q: Can you provide sample ?
A: Yes. We can provide the small samples in stock for free, as long as you contact us.Customized samples will take about 5-7 days.