GB 1499.1-2024 governs hot-rolled plain round bars (HRB) used to reinforce concrete, with stringent requirements to ensure structural integrity:
Dimensions: Diameters 6–22mm, with tolerance ±0.3mm to guarantee consistent concrete coverage and load distribution.
Chemical composition: C ≤0.22%, Mn 0.30–1.20%, P ≤0.045%, S ≤0.045%-minimizing corrosion risk and ensuring weldability for prefabricated structures.
Mechanical properties: Yield strength ≥300 MPa, tensile strength ≥420 MPa, and elongation ≥17% to resist seismic forces and prevent brittle failure.
Testing protocols: Mandatory tensile, bend, and chemical analysis for each production batch. Bars ≥16mm require ultrasonic testing to detect internal defects like cracks or inclusions.
These bars are marked with "GB 1499.1" and grade (e.g., HRB400) for traceability. They compete globally with ASTM A615 (USA) and EN 10080 (EU), with GB 1499.1-2024 updating corrosion resistance clauses to match international standards. Made-in-China listings often highlight these bars as "GB 1499.1 Concrete Reinforcement Round Bar-High Strength."