Structural Seamless Pipe
Standards:
GB/T8162 —— China national standards
ASTM A53 —— American Materials and Testing institution standards
ASME SA53 —— American Boiler and Pressure Vessel norms
Uses:
For the seamless steel pipes for containers, equipment, pipe,
mechanical structures
No. of main production:
10,20,35,45,Q345,15CrMo,12Cr1MoV,A53A,A53B,SA53A,SA53B ect.
Dimensional tolerance:
| Pipe types | Outer-caliber(D) | Thickness(S) |
| Pipe outer-caliber(mm) | Allowable warp(mm) | Pipe thickness(mm) | Allowable warp(mm) |
| Hot-rolled pipes | ＞219 | ±1.0％ | ＞20 | ±10％ |
Mechanical Properties:
| Standards | Steel pipes No. | Tensile strength(MPa) | Bend strength(MPa) | Elongation(％) |
| GB/T8162 | 10 | ≥335 | ≥205 | ≥24 |
| 20 | ≥390 | ≥245 | ≥20 |
| 35 | ≥510 | ≥305 | ≥17 |
| 45 | ≥590 | ≥335 | ≥14 |
| Q345 | ≥490 | ≥325 | ≥21 |
| 15CrMo | ≥440 | ≥295 | ≥22 |
| 12Cr1MoV | ≥490 | ≥245 | ≥22 |
ASTM A53 ASME SA53 | A | ≥330 | ≥205 | Table View ASTM A53 Table View ASTM SA53 |
| B | ≥415 | ≥240 |
Chemical composition:
| Standards | Steel pipes No. | Chemical composition(％) |
| C | Si | Mn | P | S | Cu | Ni | Mo | Cr | V |
| GB/T8162 | 10 | 0.07～0.14 | 0.17～0.37 | 0.35～0.65 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.25 | / | ≤0.15 | / |
| 20 | 0.17～0.24 | 0.17～0.37 | 0.35～0.65 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.25 | / | ≤0.25 | / |
| 35 | 0.32～0.40 | 0.17～0.37 | 0.50～0.80 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.25 | / | ≤0.25 | / |
| 45 | 0.42～0.50 | 0.17～0.37 | 0.50～0.80 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.25 | / | ≤0.25 | / |
| Q345 | 0.12～0.20 | 0.20～0.55 | 1.20～1.60 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.25 | / | ≤0.25 | / |
| 15CrMo | 0.12～0.18 | 0.17～0.37 | 0.40～0.70 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.30 | 0.40～0.55 | 0.80～1.10 | / |
| 12Cr1MoV | 0.08～0.15 | 0.17～0.37 | 0.40～0.70 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.30 | 0.25～0.35 | 0.90～1.20 | 0.15～0.30 |
ASTMA53 ASMESA53 | A | ≤0.25 | / | ≤0.95 | ≤0.05 | ≤0.06 | ≤0.40 | ≤0.40 | ≤0.15 | ≤0.40 | ≤0.08 |
| B | ≤0.30 | / | ≤1.20 | ≤0.05 | ≤0.06 | ≤0.40 | ≤0.40 | ≤0.15 | ≤0.40 | ≤0.08 |
Structural tubing is a category of hollow steel sections (HSS)
manufactured to specific sizes, shapes, and mechanical properties
for use in load-bearing applications within construction and
various industries. Unlike solid bars, its tubular design offers an
exceptional strength-to-weight ratio, making it a fundamental and
efficient material for building frameworks, supports, and
architectural elements. It is designed to withstand high loads,
including tension, compression, and torsional forces.
Materials and Grades
Structural tubing is primarily made from carbon steel, known for
its high strength and durability. Common grades include:
ASTM A500: The most prevalent standard for structural tubing in
North America, available in Grades A, B, C, and D, with increasing
yield strength.
ASTM A1085: A newer standard that offers higher strength and
tighter tolerances than A500, promoting more efficient and
economical designs.
ASTM A53: A standard for both pressure and structural applications,
though more common for piping.
Alloy Steel & Stainless Steel: Used for specialized applications
requiring higher corrosion resistance or strength in extreme
environments.
These materials can be further enhanced with protective coatings
like galvanization (zinc coating) or paint to improve corrosion
resistance.
Manufacturing Processes
There are two primary methods for manufacturing structural tubing:
Welded Tube (ERW): Electric Resistance Welded (ERW) tube is formed
by rolling steel strip (skelp) into a cylindrical shape and then
welding the seam using an electric current. This is a highly
efficient process suitable for a wide range of sizes and is the
most common type for structural
Applications:
Seamless Tube: Made by piercing a solid billet of steel to form a
hollow shell, which is then elongated and rolled to achieve the
desired size and wall thickness. Seamless tubing offers superior
uniformity in strength around its circumference and is used for
highly critical applications but is generally more expensive.
