ASTM A252 — Welded and seamless steel pipe piles
Grades
Gr.1, Gr.2, Gr.3
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| Gr.1 | C≤0.30, Mn 0.40-1.06, P≤0.025, S≤0.025 | Rm ≥380 MPa, Rp0.2 ≥205 MPa, A≥30% (longitudinal), Akv≥18J at -45℃ |
| Gr.2 | C≤0.21, Mn 0.55-0.80, P≤0.025, S≤0.025, Si 0.15-0.40, Cr 0.50-0.80, Mo 0.45-0.60 | Rm 380-550 MPa, Rp0.2 ≥230 MPa, A≥18%, Normalizing + Tempering |
| Gr.3 | C≤0.19, Mn≤0.70, P≤0.025, S≤0.025, Ni 3.18-3.82 | Rm ≥450 MPa, Rp0.2 ≥240 MPa, A≥30% (longitudinal), Akv≥18J at -100℃, normalizing |
Application scope
ASTM A252 specifies welded (and seamless) steel pipe piles for bridge, building, and other structural foundations, categorized into three strength grades: 1, 2, and 3. The standard specifies chemical composition, tensile properties, and weld requirements, emphasizing the pile's load-bearing capacity, driving force, and bending resistance. Grade 3 has higher strength. Pipe piles can be extended and cast in place, making them suitable for deep foundations and support works bearing axial and lateral loads.
Typical applications
Widely used in deep foundation engineering such as bridge and building pile foundations, wharf and trestle pile foundations, foundation pit support, and offshore platform piles, steel pipe piles can be used as end-bearing piles or friction piles, and are often filled with concrete to form composite piles. With their excellent bearing capacity, bending resistance, and ease of driving and extending, steel pipe piles are suitable for foundation engineering with large loads, complex geology, or construction in water areas, making them an important type of pipe for structural foundations.
