JIS G3455 — Carbon steel pipes for high-pressure pipelines
Grades
STS370, STS410, STS480
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| STS370 | C≤0.25, Mn 0.30-1.10, P≤0.035, S≤0.035, Si 0.10-0.35 | Rm ≥370 MPa, Rp0.2 ≥215 MPa, A≥30% |
| STS410 | C≤0.30, Mn 0.30-1.10, P≤0.035, S≤0.035, Si 0.10-0.35 | Rm ≥410 MPa, Rp0.2 ≥245 MPa, A≥25% |
| STS480 | C≤0.33, Mn 0.30-1.10, P≤0.035, S≤0.035, Si 0.10-0.35 | Rm ≥480 MPa, Rp0.2 ≥275 MPa, A≥22% |
Application scope
JIS G3455 specifies carbon steel pipes for high-pressure pipelines, with three grades: STS370, STS410, and STS480, designed for high-pressure pipeline systems. The standard imposes stricter requirements on chemical composition, tensile properties, and process testing, with more stringent impurity control. Strength increases with each grade, providing good pressure resistance and weldability, making it suitable for welded connections in power and process pipelines under high-pressure conditions.
Typical applications
Commonly used in high-pressure boiler piping, high-pressure process piping, high-pressure feedwater and steam pipelines, and other systems subjected to high pressure, with strength increasing sequentially among the grades, selectable according to pressure rating. With stricter control over composition and impurities, as well as excellent high-pressure bearing and weldability, it can operate safely under higher pressures, making it suitable for medium- and high-pressure pipeline projects in the power, petrochemical, and chemical industries where pressure-bearing safety requirements are high.
