A500C · Ø6–40 · 6–12 m · GOST 34028-2016
A500C rebar
Weldable grade 500 rebar to GOST 34028-2016, crescent rib pattern, Ø6–40 mm, from mills in China
A400 (A-III) · Ø6–40 · 25G2S, 35GS · GOST 5781-82
A400 (A-III) rebar
Hot-rolled grade A-III rebar to GOST 5781-82 from steel 25G2S and 35GS, herringbone rib pattern, Ø6–40 mm
GOST 5781-82GOST 34028-201625G2S35GS
Parameters
| Parameters | |
|---|---|
| Grade | A-III (A400) |
| Steel grade | 25G2S, 35GS |
| Diameter | 6–40 mm |
| Length | 6–12 m fixed length, 11.7 m; Ø6–8 mm in coils |
| Yield strength | from 390 N/mm² |
| Tensile strength | from 590 N/mm² |
| Rib pattern | two longitudinal ribs, transverse ribs on opposing helical lines — “herringbone” |
Sizes and weight
| Ø, mm | Weight, kg/m | Metres per tonne |
|---|---|---|
| 6 | 0.222 | 4 505 |
| 8 | 0.395 | 2 534 |
| 10 | 0.617 | 1 622 |
| 12 | 0.888 | 1 126 |
| 14 | 1.21 | 827.5 |
| 16 | 1.58 | 633.6 |
| 18 | 2 | 500.6 |
| 20 | 2.47 | 405.5 |
| 22 | 2.98 | 335.1 |
| 25 | 3.85 | 259.5 |
| 28 | 4.83 | 206.9 |
| 32 | 6.31 | 158.4 |
| 36 | 7.99 | 125.2 |
| 40 | 9.86 | 101.4 |
Theoretical weight at steel density 7.85 g/cm³. Actual batch weight is by scale and mill certificate.
Description
A400 is a rebar grade with a yield strength of 390 N/mm² or more, designated A-III in GOST 5781-82. Tensile strength is 590 N/mm² or more, elongation δ5 is 14 % or more, and the cold bend test is 90° around a mandrel of 3d diameter. The strength comes from alloying the steel rather than from heat treatment, so the mechanical properties are retained under heating and welding.
It is hot-rolled from low-alloy steel 25G2S or 35GS — manganese and silicon provide the strength, with carbon content of 0.20–0.29 % and 0.30–0.37 % respectively. The GOST 5781 pattern is two longitudinal ribs and transverse ribs running along helical lines towards each other — the herringbone pattern. Steel 25G2S is weldable by all methods, 35GS to a limited extent: by resistance welding, while arc welding is by a procedure agreed with the structural designer or with replacement by 25G2S.
During inspection at the mill the bureau checks the steel grade on the mill test certificate (MTC) against the order — for welded cages specifically 25G2S is confirmed — and the heat number against the bundle tag. The diameter is measured with a calliper over the longitudinal ribs and at the core, the height of the transverse ribs with a micrometer, and the weight of a one-metre sample on scales. Lengths, bundle strapping and the rolled-in marks on the bar are checked; the inspection report with photographs is attached to the shipping documents.
Applications
- precast concrete units and floor slabs
- cast-in-place foundations and columns
- structures with main reinforcement designed to GOST 5781
- tied cages and meshes
- structures exposed to heat in service
Packing and shipment
Bundles of 2–3 t strapped with steel band, mill tag with grade, steel grade, diameter, heat number and weight; Ø6–8 mm in coils.
Grade equivalents
| GOST | GB (China) | ASTM | EN | Note |
|---|---|---|---|---|
| A240 (GOST 34028), A-I (GOST 5781) | HPB300 (GB/T 1499.1) | Grade 40 [280] | — | Plain round bar. Yield strengths differ: 240, 300 and 280 N/mm². |
| A400 (GOST 34028) | HRB400 / HRB400E | Grade 60 [420] | — | Nearest equivalents by yield strength of 400–420 N/mm². Grade 60 under ASTM A615 is not intended for welding. |
| A-III / A400 (GOST 5781, 25G2S, 35GS) | HRB400 / HRB400E | Grade 60 [420] | — | Nearest equivalent. Steel 35GS has limited weldability; HRB400 is rolled from microalloyed steel with a carbon equivalent of up to 0.54 %. The GOST 5781 rib pattern is herringbone, the GB pattern is crescent. |
| A500C (GOST 34028) | HRB500 / HRB500E | Grade 75 [520] | B500B | B500B (BS 4449, DIN 488 within EN 10080) is the equivalent by yield strength of 500 N/mm²; HRB500E and Grade 75 are the nearest equivalents. A500C is weldable, carbon equivalent up to 0.52 %. |
| A500C (GOST 34028) | HRB400E | Grade 60 [420] | B500B | Replacing A500C with HRB400E lowers the design strength and requires the reinforcement to be recalculated — only with the structural designer's approval. |
| A600 (GOST 34028) | HRB600 | Grade 80 [550] | — | Nearest equivalents: yield strength 600, 600 and 550 N/mm². |
Equivalents are the closest match, not identical: chemistry and tolerances differ between standards. The exact grade and standard are written into the contract.
Related items
HRB400E · Ø6–50 · 9–12 m · GB/T 1499.2-2018
HRB400E rebar
Hot-rolled seismic grade 400 rebar to GB/T 1499.2-2018, Ø6–50 mm, the standard product of mills in China
Buyer questions
How to read a mill test certificate (MTC) for rebar
The certificate states the standard and grade, diameter, heat number, chemical composition of the heat with the carbon equivalent, tensile test results (yield strength, tensile strength, elongation) and bend test results, weight and number of bundles. The heat number on the certificate is checked against the tag on every bundle and the rolled-in marking on the bar — this is the link between the document and the metal. The bureau's inspector makes this check at the mill before shipment and attaches the certificate to the inspection report.
How A500C differs from A400 (A-III) and from HRB400E
By yield strength and by how the strength is obtained. A400 under GOST 5781 is hot-rolled from low-alloy steel 25G2S or 35GS, yield strength from 390 N/mm², herringbone rib pattern. A500C under GOST 34028 is as a rule thermomechanically strengthened low-carbon steel, yield strength from 500 N/mm², weldable, crescent rib pattern. HRB400E under GB/T 1499.2 is hot-rolled microalloyed steel, yield strength from 400 N/mm², with seismic ductility requirements. The grade for a project is set by the structural designer; the bureau selects a mill for the specified grade.
How the tonnage of a batch is calculated
A specification in metres is converted to tonnes by theoretical weight: the weight per metre equals 0.006165·d², where d is the nominal diameter in millimetres. The weight tables on the product pages are built on this formula at a steel density of 7.85 g/cm³. Shipment and acceptance are by actual weight as recorded on the mill's certificate and packing list; the deviation of actual weight from theoretical is limited by the tolerance of the standard.
What the bureau's inspector checks at the mill before shipment
That the batch matches the order by standard, grade and diameters; nominal diameter and rib height with a calliper and a micrometer, the weight of a one-metre sample on scales; the rolled-in marking on the bar and the tag on the bundle — grade, diameter, heat, mill; the mill test certificate for every heat; packing and strapping of bundles. The result is an inspection report with photographs. Rejects recorded in the report are replaced — the replacement is supplied by the mill under its contract with the bureau.
What the minimum batch is and whether several diameters can be combined in one shipment
The batch is sized to your volume — send a specification with grade, diameters, lengths and quantity for each item. Several diameters of one grade are collected at one mill into one shipment; where standards or grades differ, the bureau selects a mill that rolls all the required items or consolidates the shipment from two mills.
Price request
Send your specification and we will quote your batch
Steel pricing depends on grade, size, tonnage and delivery terms on the day of contract. A number on the page would be wrong by the time you read it.
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