ASTM A554 — Welded stainless steel mechanical pipe
Grades
TP304, TP304L, TP316, TP316L, TP409, TP430, TP439, TP441, TP444
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| TP304 | C≤0.08, Si≤0.75, Mn≤2.00, P≤0.045, S≤0.030, N≤0.10, Cr 18.00-20.00, Ni 8.00-11.00 | Rm ≥515 MPa, Rp0.2 ≥205 MPa, A≥40%, HB≤201, austenitic 304 |
| TP304L | C≤0.030, Si≤0.75, Mn≤2.00, P≤0.045, S≤0.030, N≤0.10, Cr 18.00-20.00, Ni 8.00-12.00 | Rm ≥485 MPa, Rp0.2 ≥170 MPa, A≥40%, HB≤201, austenitic ultra-low carbon 304L |
| TP316 | C≤0.08, Si≤0.75, Mn≤2.00, P≤0.045, S≤0.030, N≤0.10, Cr 16.00-18.00, Ni 10.00-14.00, Mo 2.00-3.00 | Rm ≥515 MPa, Rp0.2 ≥205 MPa, A≥40%, HB≤217, austenitic with Mo 316 |
Application scope
ASTM A554 specifies weldable stainless steel tubing for mechanical, decorative, and general purposes. Grades cover both austenitic and ferritic microstructures and are available in a variety of cross-sections and surface finishes. The standard emphasizes the appearance, dimensional accuracy, and formability and weldability of the tubing, while also considering corrosion resistance and aesthetics. Ferritic grades offer greater economic benefits and oxidation resistance, making them suitable for applications requiring both decorative appeal and light structural loads.
Typical applications
Widely used in architectural decoration, railings, door and window components, curtain wall components, as well as frames and exterior parts for furniture, kitchenware, and bathroom products. Austenitic varieties offer good appearance and corrosion resistance, while ferritic varieties are commonly used in heat- and corrosion-resistant components such as automotive exhaust systems. Due to their excellent polishing properties and formability, they are also used in light-duty machinery and decorative structural pipes such as display shelves and instrument supports.
