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Stainless Steel Alloy 630 Pipe

Stainless steel alloy 630 pipe (UNS S17400) is a martensitic precipitation hardening stainless steel pipe, also known as 17-4PH. Through solution treatment and aging heat treatment, a copper-rich phase is precipitated in the martensitic matrix to achieve a composite performance of high strength and corrosion resistance. The tensile strength can reach more than 1000MPa. At the same time, it has a pitting resistance close to that of 316L stainless steel. It can be used in chloride ion environments and is widely used in aerospace (such as landing gear tubes), medical equipment (surgical instruments), marine engineering (corrosion-resistant pipelines) and other fields.
Product Description

630 Stainless Steel Pipe for Aerospace can achieve a tensile strength exceeding 1310 MPa through aging heat treatment (e.g., aging at 480°C), in accordance with ASTM A564. Its hardness can reach HRC 40–44, significantly higher than that of 304 stainless steel (tensile strength ≤700 MPa). Surface hardness can be further enhanced to HV 1000+ through nitriding or PVD coating, reducing wear and extending the service life of moving components such as pump shafts and piston rods. This makes it ideal for high-load structural parts such as aerospace fasteners and high-pressure valve stems.

In addition, Alloy 630 seamless pipe, after solution annealing and aging, exhibits uniform precipitation at grain boundaries. This microstructure provides a higher stress corrosion cracking (SCC) threshold in chloride-containing environments compared to 304, making it well-suited for chemical pressure vessels, nuclear steam piping, and other critical high-stress applications.

Stainless Steel 630 Precision Pipe Applications

Stainless Steel 630 Precision Pipe Applications

Data table

AISI 630 SS Tubes specification

Grade Stainless Steel Alloy 630 / 17-4PH / UNS S17400
Standards ASTM A564 / A705, AMS 5568 (for pipe/tube)
Pipe Type Seamless / Welded / Cold Drawn
OD Range 6 mm – 219 mm
Wall Thickness 0.5 mm – 20 mm
Delivery Condition Solution Annealed + Aged (H900 / H1025 / H1150)

Chemical Composition Of 630 Pipe

Grade

C

Mn

Si

P

S

Cr

Ni

Cu

Nb+Ta

630

min.

max

-

0.07

-

1

-

1

-

0.04

-

0.030

15

17.5

3

5

3

5

0.15

0.45

Mechanical Properties Of 630 Stainless Pipe

Condition

Tensile Strength (MPa)

Yield Strength 0.2% Proof (MPa)

Elongation (% in 50mm)

Hardness

Rockwell C (HR C)

Brinell (HB)

Solution Treated

1105 typ

1000 typ

15 typ

38 max

363 max

Condition 900

1310 min

1170 min

10 min

40 min

388 min

Condition 1150

930 min

724 min

16 min

28 min

277 min

company advantage

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FAQ

Q.What are the standard specifications and implementation standards for 630 stainless steel pipes?
A.Specifications: The outer diameter range is usually 6-610mm, the wall thickness is 0.5-40mm, and it can be customized;
Implementation standards: ASTM A564 (seamless pipe), ASTM A731 (welded pipe), JIS G4305 (Japanese standard), etc.

Q.Is 630 stainless steel pipe magnetic?
A.Yes. After aging treatment, 630 is mainly martensitic structure and has obvious magnetism, which is different from the non-magnetic 304/316 austenitic stainless steel.

Q.How much higher is the price of 630 stainless steel pipe than 304?
A.Due to the complex composition (including copper and niobium) and heat treatment process, the price of 630 is usually 30%-50% higher than 304, depending on the specifications and purchase volume.

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