What is A500 GRD made of?
A500 GR.D (or written GRD) is the highest strength grade of carbon steel square/rectangular tube material for structural use in the ASTM A500 standard, designed for heavy-duty and severe service conditions, with the following core properties:
1. Material Properties
Standard attributes: Meets the requirements of ASTM A500 Grade D for cold formed welded/seamless structural steel tubing.
Chemical Composition: Based on low carbon steel with carbon content ≤0.27% and manganese content ≤1.40%, with enhanced alloying elements to improve overall performance.
Mechanical properties:
Tensile strength ≥483 MPa, yield strength ≥345 MPa (significantly higher than GR.B and GR.C grades);
Elongation ≥18%, combining high strength and toughness.
2. Technology and product form
Manufacturing process: High-frequency welding (ERW) or seamless production, cold roll forming needs to be normalised to eliminate residual stresses;
Typical specifications: square/rectangular section side length 20-500mm, wall thickness 2-20mm, length 6-12 metres.
3. Areas of application
Building structure: steel frame of super high-rise building, large-span bridge support;
Heavy machinery: crane jib, mining equipment load-bearing parts;
Marine engineering: deep-sea platform structural tubes, high-strength connectors for ships.
4. Comparison with other grades
Comparison of GR.B/GR.C: GR.D has higher tensile strength (≥483 MPa) and yield strength (≥345 MPa) than GR.B (≥400/290 MPa) and GR.C (≥455/345 MPa), and is suitable for extreme loading scenarios C (≥455/345 MPa) for extreme loading scenarios;
Comparison of alloy steel: GR.D is made of carbon steel, which is less costly than high-alloy steel, but it should be noted that the corrosion resistance is weaker.
5. Market information (2025 reference)
Price range: about RMB 4300-5330/tonne (subject to specifications, process and regional supply and demand);
Suggestions for selection: It is necessary to verify the material certificate (MTC) provided by the supplier to confirm that the mechanical properties and chemical composition are up to standard.
Note: If corrosive environments are involved, it is recommended to galvanise or coat GR.D steel pipes for anti-corrosion treatment
