17-4 PH stainless steels is a martensitic precipitation-hardenable stainless steel comprised of 15-17.5% chromium, 3-5% nickel, and 3-5% copper, with 17% chromium and 4% nickel giving it its name.
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.
17-4PH Chemical Composition
|Weight%||C||Si||Mn||ph||S||Cr||Ni||Cb + Ta||Cu|
17-4PH Typical Physical Properties
|Density||Modulus of Elasticity||Thermal Conductivity||Specific Heat||Melting Range|
|7.75 g/cm³||196 GPa||18.3 W/m.K||460 J/kg-°C||1404 – 1440°C|
17-4PH Mechanical Properties
|Condition||Tensile Strength (MPa)||Yield Strength 0.2% Proof (MPa)||Elongation (% in 50mm)||Hardness Brinell (HB)|
|Solution Treated||1105 typ||1000 typ||15 typ||363 max|
|Condition 900||1310 min||1170 min||10 min||388 min|
|Condition 1150||930 min||724 min||16 min||277 min|
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.
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.
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:
|Cond.||Temp (°C)||Time (h)||Typical Hardness Rockwell C||Tensile Strength (MPa)|
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.
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.
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.
Thermal cutting operations such as plasma cutting should be avoided. Mechanical cutting operations such as bandsaw, abrasive waterjet, shearing and machining are preferred.
Alloy 17-4PH can be readily welded by most standard processes including SMAW, GTAW, PAW and GMAW.
- Bars & Rods & Foring Ring /Flanges
- Sheet & Plate
- Strip & Coil
- Welding Wire &Spring wire
- Seamless Tube & Welded Pipe
»Round Bar & Square Bar & Hexagon Bar
● Diameter : φ8～φ300mm Length:10mm-6000mm
● Hot forging, Hot Rolling, Cold Drawing
● Bright Surface, Polished Surface, Black Surface
»Tube & Pipe:Seamless Tube& Welded Pipe
● Cold Drawing Seamless Pipe： φ1.0～φ220mm
● Hot Extrusion pipe: φ50～φ250mm
● Others : U Blend Tube and Elbow
»Hot Rolled Plate & Cold Rolled Sheet
● Cold Rolling Sheet Thickness: ≦2.0mm Width:≦1500m
● Hot rolling Plate Thickness: ≧4.0mm Width: ≦2500m
»Strip & Tape Ribbon
● Thickness: ≧ 0.01mm Width: 15mm-300mm
● Cold rolling BA Strip, Hard & Soft Condition
»Straight Length Wire & Spool Wire
● Welding Wire: φ 0.1mm～6.0mm Cut length Rod: φ1.0～φ8.0mm
● Package : 5-25kg/Spool or Box
- Chemical Processing
- Food Process Equipment
- Gate Valves
- Mechanical Components
- Nuclear Waste Processing and Storage
- Oil and Gas Production
- Pulp and Paper