F A Q
Q: 1. What is Grade 60 rebar?
A: Grade 60 is the strength rating of steel bars in the American standard (ASTM A615), which means that they have a minimum yield strength of 60,000 psi (about 414 MPa) and a tensile strength of not less than 90,000 psi (about 621 MPa).
Q:2. What is the difference between Grade 60 and other strength grades?
A:
| Strength Grade | Yield Strength (psi) | Tensile Strength (psi) | Typical Application Scenarios |
|---|---|---|---|
| Grade 40 | 40,000 (276 MPa) | 60,000 (414 MPa) | Small-scale buildings, non-load-bearing structures |
| Grade 60 | 60,000 (414 MPa) | 90,000 (621 MPa) | Load-bearing structures such as high-rise buildings, bridges, and highways |
| Grade 75 | 75,000 (517 MPa) | 100,000 (690 MPa) | Special projects like long-span bridges and nuclear power plants |
Q: 3. What standard does Grade 60 rebar follow?
A: The main implementation of ASTM A615 "Standard Specification for Deformed and Smooth Carbon Steel Bars for Concrete" may also involve:
ASTM A706 Standard Specification for Low-Alloy Deformed Steel Bars for Concrete (for Seismic Design).
ACI 318 Code for Concrete for Building Structures (Design Application Standard).
Q: 4. What are the common specifications for Grade 60 rebar?
A: Diameter (nominal size):
#3 (9.5 mm), #4 (12.7 mm), #5 (15.9 mm), #6 (19.1 mm), #7 (22.2 mm), #8 (25.4 mm), #9 (28.7 mm, equivalent to 1 inch), etc.
Length: Typically straight bars (20-60 feet, about 6-18 meters) or coils (for small diameters such as #3-#5).
Surface Morphology: Ribbed (deformed steel bar) with ribbed design to ASTM A615 for enhanced adhesion to concrete.
Q: 5. What is the material composition of Grade 60 rebar?
A: Main ingredients: low carbon steel (carbon content ≤ 0.25%), adding manganese (Mn, 0.8-1.6%), silicon (Si) and other elements to enhance strength, phosphorus (P) and sulfur (S) content ≤ 0.05% to ensure toughness.
Alloy type: Divided into ordinary carbon steel (ASTM A615) and low alloy steel (ASTM A706, containing chromium, nickel, etc., for seismic resistance).
Q: 6. What mechanical properties are tested for Grade 60 rebar?
A: Tensile test:
Yield Strength: ≥60,000 psi.
Tensile Strength: ≥90,000 psi.
Elongation: ≥8% at 20" gauge (#11 and below).
Flexure test: 180° bending around the mandrel of the specified diameter without cracks on the surface.
Weight deviation: The actual weight is ≤4% off the theoretical weight (ASTM A615 requirements).
Q: 7. How is Grade 60 rebar used in construction?
A: Civil buildings: beams and columns, floor slabs, and wall reinforcement of high-rise buildings.
Infrastructure: load-bearing structures such as bridges, tunnels, highways, dams, etc.
Industrial engineering: concrete frames for warehouses and workshops, equipment foundations.
Special Scenario: Seismic Design Structures (ASTM A706 Low Alloy Version Required).
Q: 8. What are the connection methods of Grade 60 rebar?
A: Lashing connections: for diameters ≤ #5 (15.9 mm) and lap lengths are determined according to design specifications (e.g. ACI 318).
Welding: Arc welding (to ensure that the weld does not reduce the yield strength) is only available for specific diameters and materials.
Mechanical connections: Use sleeves or extrusion joints, suitable for large diameter rebar (e.g. #6 and above) to improve connection strength and construction efficiency.
Q: 9. What are the anti-rust treatments for Grade 60 rebar?
A: Surface galvanizing: hot-dip galvanizing or electro-galvanizing, suitable for humid environments (such as coastal engineering).
Epoxy coating:
○ Chloride ions in steel bars and concrete are isolated by electrostatic spraying of epoxy resin, which is often used in bridges or parking lots.
○ Stainless steel composite layer: used in special scenarios, the cost is high.
Q: 10. What should I pay attention to when transporting and storing Grade 60 rebar?
A: Transport:
○ The straight bar steel bar needs to be fixed on the frame to avoid bumps and bending; The coiled steel bars are fixed with a special bracket to prevent loosening.
○ When shipping, it is necessary to prevent moisture and avoid sea erosion (can be covered with a tarp).
Storage:
○ Store in a dry, ventilated place with a ≥6" (15 cm) elevated bottom to avoid contact with moisture from the floor.
○ Stacked according to specifications and batches, with clear identification (indicating diameter, strength grade, furnace batch number).
Q: 11. How do I convert Grade 60 rebar to Chinese standard rebar?
A: Strength Benchmarking:
○ Grade 60 (414 MPa) ≈ China HRB400 (yield strength ≥ 400 MPa).
○ Grade 75 (517 MPa) ≈ HRB500 (yield strength ≥ 500 MPa).
Diameter Conversion:
○ #4 (12.7mm) ≈ China 12mm; #8 (25.4mm) ≈ China 25mm.
Q: 12. How can I test the quality of Grade 60 rebar?
A: Appearance inspection: the ribs are clear, no cracks, scars, and no serious rust on the surface (floating rust is acceptable).
Dimensional measurements: Diameter, rib height, spacing must meet ASTM A615 Table 3 requirements (e.g., #4 rebar diameter allowable deviation ±0.03 inches).
Certificate verification: Suppliers are required to provide material certificates, including chemical composition and mechanical property test data.
Third-party testing: Samples are sent to the laboratory for tensile and flexure tests to confirm whether they meet the standards.
Q: 13. What factors affect the price of Grade 60 rebar?
A: Raw material costs: Affected by fluctuations in iron ore and coke prices, U.S. steel production capacity will also affect local prices.
Specifications & Shapes: Large diameters (e.g. #9), coil forms (require additional winding process) are more expensive.
Surface treatment: Epoxy coated, galvanized steel bars are 15%-30% more expensive than ordinary steel bars.
Distance: Imported steel bars (e.g. from Canada, Mexico) need to consider customs duties and logistics costs.
Market demand: Prices typically rise during the peak infrastructure season (spring to autumn).
Q: 14. Do I need to remove rust before using Grade 60 rebar?
A: Slight floating rust: It can be removed by machinery (such as wire brushes, rust removers) or natural rust (which can be ignored when it does not affect performance).
Severe rust: Mechanical properties should be tested for rust scale or pits on the surface, and should not be used if the yield strength decreases by more than 5% (refer to ASTM A615 Clause 8.2).
