GB 1499.2: Hot Rolled Ribbed Steel Bars HRB400, HRB500, HRB600 — Full Specification

Quick Answer

GB 1499.2 (current edition: 2018, replacing the 2007 edition) is a mandatory national standard (强制性国家标准, GB as opposed to GB/T) issued by the Standardization Administration of China. It governs hot-rolled ribbed steel bars — known in China as 螺纹钢 (luówén gāng, threaded steel) or 带肋钢筋 (dài lèi gāngjīn, ribbed rebar) — for use as reinforcement in concrete structures.

The 2018 revision strengthened carbon equivalent (CEV) controls, added the HRB600 and HRB600E grades, tightened chemical limits for E-grades, and increased the minimum total elongation requirement for E-grades from Agt ≥ 7.5% to Agt ≥ 9%.

Grade designation: HRB = Hot-Rolled Ribbed Bar; the number = minimum yield strength in MPa; E suffix = seismic/ductile grade (抗震).

---

Scope and Applicability

GB 1499.2 applies to:

• Deformed (ribbed) reinforcing bars for reinforced and prestressed concrete structures
• Nominal diameters from 6 mm to 50 mm (standard sizes: 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 32, 36, 40, 50 mm)
• Supplied in straight lengths (typically 9 m, 12 m) or coil (wire rod form for smaller diameters)

The standard does not cover:

• Plain (smooth) reinforcing bars — see GB 1499.1 (HPB300)
• Prestressed strand or wire — see GB/T 5223
• Cold-worked or cold-rolled bars
• Stainless steel rebar

E-grade mandatory scope: According to GB 50011 (Code for Seismic Design of Buildings) and GB 50010 (Code for Design of Concrete Structures), E-grade bars are required for frame columns, shear walls, and coupling beams in seismic design categories II, III, and IV in China.

---

Grade Coverage

E-grades carry the same strength requirements as the base grade but impose additional constraints on strength ratio (Rm/ReH) and uniform elongation (Agt) to ensure seismic ductility.

---

Chemical Composition Requirements

Ladle (heat) analysis. All values wt% maximum unless noted. CEV formula: CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15.

Standard Grades (HRB400, HRB500, HRB600)

Seismic Grades (HRB400E, HRB500E, HRB600E)

Note: The 2018 edition requires that the product analysis (取样分析) for P and S shall not exceed the ladle analysis limits by more than 0.005% each. For bars supplied in coil, the same chemistry limits apply.

Microalloying: Vanadium (V), niobium (Nb), or titanium (Ti) may be used singly or in combination. When V is used, the V content shall not exceed 0.12%; when Nb is used, Nb ≤ 0.06%; when Ti is used, Ti ≤ 0.05%. Total V + Nb + Ti ≤ 0.20%.

Nitrogen: If nitrogen (N) exceeds 0.012%, Vanadium content shall be ≥ 4 × N (V/N ≥ 4) to fix nitrogen as VN.

---

Mechanical Properties

Tensile tests per GB/T 228.1 on bar specimens (full cross-section, gauge length = 5d or 10d). Bend tests per GB/T 232.

Standard Grades

E-Grades (Seismic / Ductile)

Definitions:

• ReH = upper yield strength (or proof strength Rp0.2 if no clear yield point)
• Rm = ultimate tensile strength
• A = percentage elongation after fracture (gauge length L₀ = 5d)
• Agt = total elongation at maximum force (uniform elongation); measured over 100 mm gauge

Additional E-grade requirement: The actual yield strength (ReH, measured) must not exceed ReH min × 1.30 (i.e., ReH,actual ≤ 520 MPa for HRB400E, ≤ 650 MPa for HRB500E, ≤ 780 MPa for HRB600E). This upper-bound yield control prevents over-strong bars from shifting plastic hinges away from intended locations in seismic frames.

---

Bend Test Requirements

Bend test per GB/T 232. The bar is bent 180° around a mandrel. No cracks or delamination permitted on the outer surface after bending.

Reverse bend test (反向弯曲试验): Required for E-grade bars when specified on the purchase order (per seismic design code GB 50011 Appendix). The bar is bent 90° around the mandrel, then reverse-bent 20° in the opposite direction after aging at 100 °C for 60 minutes. No cracks permitted.

---

Rib Geometry Requirements

GB 1499.2 specifies minimum transverse rib dimensions for adequate bond with concrete. All deformed bars must carry the grade mark rolled into the rib pattern.

The grade and E marks on the physical bar must match the MTC. Counterfeit or mislabelled bars are a significant quality-control concern for Chinese rebar.

---

Testing and Inspection Requirements

Per GB 1499.2 Clause 8, the following tests are required for each inspection lot (检验批):

1. Chemical analysis — one per heat (ladle analysis); product analysis permitted for dispute
2. Tensile test (ReH, Rm, A) — two specimens per lot
3. Agt measurement — two specimens per lot (E-grade mandatory, standard grade on request)
4. Bend test — two specimens per lot
5. Reverse bend test — two specimens (E-grade, if specified)
6. Weight per metre — four specimens per lot
7. Rib geometry — visual and dimensional check per lot

Lot size: ≤ 60 tonnes of the same grade, same nominal diameter, and same heat.

CNAS accreditation: Testing laboratories verifying GB 1499.2 compliance should hold CNAS (China National Accreditation Service for Conformity Assessment) accreditation — the Chinese equivalent of NABL (India) or UKAS (UK). CNAS-accredited laboratory test reports carry higher evidentiary weight than in-house mill certificates.

---

Cross-Standard Equivalents

Key difference from ASTM A615: A615 Grade 60 specifies Rm ≥ 620 MPa vs. HRB400's Rm ≥ 540 MPa. A615 does not mandate a minimum Rm/ReH ratio or Agt for standard grade; ASTM A706 is the seismic-equivalent (Rm/ReH ≥ 1.25, Agt ≥ 14%). The Chinese E-grade (Agt ≥ 9%) has a lower elongation floor than ASTM A706 (Agt ≥ 14%) but adds the upper-bound yield control (ReH,actual ≤ 1.30 × ReH,min).

---

MTC Verification Checklist

A 质量证明书 for GB 1499.2 rebar must include:

• Standard number: GB 1499.2 (and edition year — 2018 or 2007)
• Grade designation with or without E suffix (e.g., HRB400E)
• Heat number (炉号) and batch number (批号)
• Nominal diameter and nominal weight per metre
• Ladle chemistry: C, Si, Mn, P, S, and CEV (all within limits above)
• Microalloying elements: V, Nb, or Ti content as applicable
• Mechanical test results: ReH, Rm, A (and Agt for E-grades)
• For E-grades: Rm/ReH ratio (must be ≥ 1.25) and confirmation ReH ≤ 1.30 × ReH,min
• Bend test pass/fail result
• Reverse bend test result (if E-grade with seismic spec on PO)
• CNAS laboratory accreditation number for independent test reports
• Mill signature, stamp, and quality inspector name

Critical flags:

• E-grade bars with Rm/ReH < 1.25 or Agt < 9% — non-conforming, reject
• Actual yield (ReH,actual) > 1.30 × nominal (e.g., > 520 MPa for HRB400E) — seismic ductility concern
• CEV exceeding the permitted maximum for the grade — weldability concern
• Grade mark on physical bar does not match MTC grade

---

Frequently Asked Questions