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Carbon Steel Round Bar: Q235 Hot Rolled Steel Rod Guide
O carbon steel round bar is the raw material of shafts, pins, fasteners, spindles and machined parts. This guide explains the Q235 hot rolled steel rod — its chemistry, mechanical properties, standard diameters and how to buy it. All sizes are available as Q235 carbon steel round bar from QIDAMT.
What Is a Carbon Steel Round Bar?
A round bar is a solid cylindrical steel section produced by hot rolling, with a circular cross-section. Chinese production follows GB/T 702 for hot-rolled round bars, with the base grade Q235 to GB/T 700. Round bars are the starting point for turning, threading, forging and machining, and they also serve directly as anchor bars, dowels and tie rods in construction.
Compoziție chimică (Q235)
| Element | C | Si | Mn | P | S |
|---|---|---|---|---|---|
| Max (%) | 0.22 | 0.35 | 1.40 | 0.045 | 0.045 |
Mechanical Properties
- Yield strength: ≥ 235 MPa
- Tensile strength: 370 – 500 MPa
- Elongation: ≥ 26 %
- Density: 7.85 g/cm³
Standard Round Bar Diameters
| Diameter (mm) | Weight (kg/m) | Typical Length (m) |
|---|---|---|
| 10 | 0.62 | 6 / 9 / 12 |
| 12 | 0.89 | 6 / 9 / 12 |
| 16 | 1.58 | 6 / 9 / 12 |
| 20 | 2.47 | 6 / 9 / 12 |
| 25 | 3.85 | 6 / 9 |
| 32 | 6.31 | 6 / 9 |
| 40 – 100 | 9.87 – 61.65 | 6 (custom) |
| 110 – 250 | 74.60 – 385.30 | on request |
Bars over 100 mm are often forged or rolled-to-order. Tolerances follow GB/T 702 Group 2 unless otherwise specified.
Applications
Round bars serve as shafts, pins, rollers, anchor bolts, tie rods, reinforcement of frames, and raw stock for turned and machined parts. For flat sections in the same projects, combine them with Q235B carbon steel flat bar; for hollow sections, use 20# carbon steel seamless pipe.
Buying Checklist
- Specify diameter × length and total tonnage or piece count.
- Confirm the surface condition: black, peeled, or bright drawn.
- Ask whether cutting-to-length is available for large diameters.
- Check if the mill certificate is included; third-party inspection on request.
- Combine round bars, flat bars and angles in one container to optimize freight.
Send diameters, lengths and quantity — we will confirm price, stock and delivery within 24 hours.
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