1. Manufacturing Process
Applies to steel pipe (round cross-section) used for pipelines and mechanical applications.
Can be produced in two ways:
Seamless: Drawn/extruded from solid billets (no weld seam).
Welded: Made from flat sheets rolled into a cylinder and welded (e.g., ERW or SAW).
Welded A53 pipe requires testing (e.g., hydrostatic or ultrasonic) to ensure weld integrity.
Applies to structural tubing (round, square, rectangular cross-sections) used for structural supports (e.g., buildings, bridges, machinery).
Only produced as welded tubing:
Flat sheets are rolled and welded along the seam (no seamless option in this standard).
The focus is on dimensional accuracy and structural stability, not pressure/corrosion resistance.
2. Grades and Mechanical Properties
Grade A: Low-strength carbon steel (minimum yield strength ~21 ksi / 145 MPa).
Grade B: Higher-strength carbon steel (minimum yield strength ~30 ksi / 207 MPa).
Designed for pressure applications (e.g., conveying fluids, gas) or mechanical use (e.g., shafts).
Requires compliance with tensile strength, elongation, and chemical composition (e.g., carbon, manganese limits).
Divided into four grades based on manufacturing process and strength:
Grade A: Lowest strength (yield strength ~33 ksi / 228 MPa), hot-formed.
Grade B: Moderate strength (yield strength ~42 ksi / 290 MPa), hot-formed.
Grade C: Higher strength (yield strength ~50 ksi / 345 MPa), cold-formed.
Grade D: Highest strength (yield strength ~50 ksi / 345 MPa), cold-formed and stress-relieved.
Prioritizes structural integrity (e.g., bending, compression, tension) over pressure resistance.
Chemical composition requirements are less strict compared to A53.
3. Applications
Primary uses:
Pressure pipelines (water, gas, oil in non-critical systems).
Mechanical applications (e.g., boiler tubes, structural supports in low-pressure environments).
Not typically used for complex structural loads (leave that to A500).
Primary uses:
Structural framing (buildings, bridges, towers).
Mechanical components (e.g., crane booms, vehicle frames, railings).
Tubing with non-round shapes (square, rectangular) are common in this standard.
Rarely used for fluid/gas conveyance (use A53 instead).
4. Dimensional Standards
Specifies pipe dimensions by nominal pipe size (NPS) (e.g., 1", 2", up to large diameters).
Focuses on wall thickness (schedule numbers) and pressure ratings.
Specifies tubing dimensions by outer dimensions (e.g., 外径 for round tubing, side length for square/rectangular tubing).
Focuses on shape tolerance (e.g., corner radius, flatness of sides) and wall thickness consistency for structural stability.
