ASTM A778/A778M — Welded unannealed austenitic stainless steel pipe
Grades
TP304, TP304L, TP316, TP316L, TP321, TP347
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
Austenitic stainless steel tubes supplied in the weld condition, without solution annealing, according to ASTM A778/A778M specifications, are suitable for applications with low corrosion and low pressure. The grades include standard and ultra-low carbon, stabilized austenitic varieties, retaining good basic corrosion resistance and forming and welding properties. The standard emphasizes the dimensions and general mechanical requirements of larger diameter, thin-walled tubes, balancing economy and practicality.
Typical applications
Widely used in low-pressure pipelines with mild corrosion, ventilation and drainage pipes, as well as structural and decorative pipes. Lower in cost due to the elimination of solution annealing, it is suitable for water treatment, general industrial transportation, and building water supply and drainage. It is also used as a light-load structural component such as railings, supports, and frames. Due to its economy and sufficient corrosion resistance, it is commonly found in general-purpose pipelines with moderate performance requirements.
