ASTM A36 Round Bar Carbon Steel — Factory Direct Supplier | Huaxia-Steel
ASTM A36 round bar is the most widely specified carbon-steel bar in North American structural and fabrication codes. With a minimum 36 ksi (250 MPa) yield strength, good weldability and consistent mill supply, it is the default choice for general-purpose shafts, machinery parts, base plates, anchor bolts, supports and structural bracing. Huaxia Steel supplies hot-rolled A36 round bar direct from our Chinese mills in diameters from 10 mm to 300 mm (0.4" to 12"), with EN 10204 Type 3.1 mill certificate and optional third-party inspection by SGS, BV or TUV.
1. Product Overview
ASTM A36 is the U.S. standard for structural-quality carbon steel shapes, plates and bars. The standard covers hot-rolled round, square, hex and flat bars used in general construction, bridges, machinery frames, base plates and miscellaneous fabrication. Although A36 plate is the most familiar form, A36 round bar is widely used for bolts, studs, anchor rods, axles, pins, hinges and general machined parts where the chemistry of A36 delivers reliable weldability and predictable mechanical performance.
A36 round bar is produced by hot rolling billets through a continuous or reversing mill. The hot-rolled surface carries a characteristic mill scale (blue-black oxide), which is acceptable for most fabrication applications. Where a clean surface is required for machining or galvanizing, A36 bar can be shot-blasted, pickled or supplied as cold-finished bar (A36 cold drawn).
2. Chemical Composition
ASTM A36 permits a relatively wide carbon range and uses manganese as the primary strengthening element. Copper may be specified when enhanced atmospheric corrosion resistance is required (e.g. for outdoor structural applications).
| Element | ASTM A36 (%) |
|---|---|
| Carbon (C), max | 0.26 (plate); 0.27 (bar up to 20 mm); 0.28 (bar > 20–40 mm); 0.29 (bar > 40–100 mm) |
| Manganese (Mn) | 0.60 – 0.90 (no minimum for bar ≤ 20 mm); 0.60 – 1.20 (bar > 20 mm) |
| Phosphorus (P), max | 0.04 |
| Sulfur (S), max | 0.05 |
| Silicon (Si) | 0.15 – 0.40 (plates); 0.10 – 0.40 (shapes) |
| Copper (Cu), min (when specified) | 0.20 |
3. Mechanical Properties
| Property | ASTM A36 Requirement |
|---|---|
| Tensile strength | 58 – 80 ksi (400 – 550 MPa) |
| Yield strength, min | 36 ksi (250 MPa) |
| Elongation in 8 in. (200 mm), min | 20% |
| Elongation in 2 in. (50 mm), min | 23% |
4. Size Range and Dimensional Tolerances
Huaxia Steel supplies ASTM A36 round bar in the following standard size range. Mill tolerances comply with ASTM A6 / A6M for bars. Non-standard sizes can be produced to order.
| Nominal Diameter (mm) | Imperial Equivalent (in.) | Length Range | Weight per Meter (kg/m) |
|---|---|---|---|
| 10 | 0.394 | 6 – 12 m | 0.617 |
| 12 | 0.472 | 6 – 12 m | 0.888 |
| 16 | 0.630 | 6 – 12 m | 1.578 |
| 20 | 0.787 | 6 – 12 m | 2.466 |
| 25 | 0.984 | 6 – 12 m | 3.853 |
| 32 | 1.260 | 6 – 12 m | 6.313 |
| 40 | 1.575 | 6 – 12 m | 9.864 |
| 50 | 1.969 | 6 – 12 m | 15.413 |
| 65 | 2.559 | 6 – 12 m | 26.049 |
| 80 | 3.150 | 6 – 12 m | 39.456 |
| 100 | 3.937 | 6 – 12 m | 61.654 |
| 130 | 5.118 | 6 – 12 m | 104.195 |
| 160 | 6.299 | 6 – 12 m | 157.834 |
| 200 | 7.874 | 3 – 6 m | 246.615 |
| 250 | 9.843 | 3 – 6 m | 385.336 |
| 300 | 11.811 | 3 – 6 m | 554.883 |
5. Dimensional Tolerance
| Nominal Diameter | Tolerance per ASTM A6 |
|---|---|
| ≤ 25 mm | ± 0.30 mm |
| > 25 – 50 mm | ± 0.40 mm |
| > 50 – 75 mm | + 0.80 / − 0.40 mm |
| > 75 – 100 mm | + 1.20 / − 0.40 mm |
| > 100 – 200 mm | + 1.60 / − 0.80 mm |
| > 200 mm | + 2.00 / − 1.00 mm |
6. Equivalent Grades and Cross-Reference
ASTM A36 is interchangeable with several international structural-quality carbon-steel bar grades. The table below shows the most common equivalents.
| Region | Equivalent Standard / Grade |
|---|---|
| Europe (EN) | S235JR, S275JR (EN 10025-2) |
| China (GB/T) | Q235B, Q255B (GB/T 700) |
| Japan (JIS) | SS400 (JIS G3101) |
| Germany (DIN) | St37-2, St44-2 (DIN 17100, superseded by EN 10025) |
| UK (BS) | 40A, 43A (BS 4360, superseded by EN 10025) |
| India (IS) | IS 2062 E250 |
7. Common Applications
- Anchor bolts and foundation rods for towers, tanks and structural columns
- Machinery shafts, axles, pins and pivot points
- Base plates, gusset plates, stiffeners and structural bracing
- General fabrication — brackets, supports, frames and base frames
- Concrete reinforcement embed plates and embed anchors
- Handrails, ladder rungs, fence posts and guard rails
- Construction shoring, scaffolding and formwork
- Welded and bolted structural assemblies per AISC, CISC and similar codes
8. Manufacturing Standards
Huaxia Steel A36 round bar complies with the following manufacturing standards:
- ASTM A36 / A36M — Standard Specification for Carbon Structural Steel
- ASTM A6 / A6M — General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
- EN 10025-2 — Hot-rolled products of structural steels (for S235JR / S275JR equivalent supply)
- JIS G3101 — Rolled steel for general structure (for SS400 equivalent supply)
- GB/T 700 — Carbon structural steels (for Q235B equivalent supply)
9. Quality Assurance and Inspection
Every heat of A36 round bar is supplied with an EN 10204 Type 3.1 mill certificate including:
- Heat number and batch traceability
- Chemical composition (heat analysis + product analysis)
- Tensile test, yield strength, elongation
- Charpy V-notch test if specified (optional for A36)
- Hardness test (optional)
- Dimensional check report with actual diameter at multiple positions
- Surface finish and visual inspection record
For projects requiring witnessed inspection, we coordinate third-party verification by SGS, BV, TUV, Intertek or ABS. Inspection can cover production monitoring, mechanical testing, dimensional checks and pre-shipment verification.
10. Packaging and Shipping
Standard export Incoterms: FOB, CFR, CIF. Standard lead time: 15–30 days for stocked sizes, 25–50 days for non-standard sizes. Sample lot of 200–500 kg available for trial orders.
Need ASTM A36 round bar for a structural, fabrication or general-purpose project? Huaxia Steel ships mill-direct from China in diameters 10–300 mm, lengths 3–12 m, with EN 10204 3.1 certificate and SGS / BV / TUV third-party inspection available. Email [email protected] with your diameter, length, quantity, delivery port and any specification requirements, and we will respond with a quotation within 24 hours.
