I. Overview of BS 6323 Hot-Rolled Steel Tubes
BS 6323 hot-rolled steel tubes are high-quality carbon or low-alloy steel tubes manufactured in accordance with the British Standard BS 6323, specifically designed for pressure-bearing, structural, and boiler applications.
These tubes are formed through a hot-rolling process, featuring uniform wall thickness, robust mechanical properties, and excellent durability.
They are commonly utilized in applications such as high-pressure boiler piping, heat exchangers, oil and gas transmission pipelines, and structural supports in construction.
II. Material and Steel Grades of BS 6323 Hot Finished Steel Tubes
| Category | Common Steel Grades / Designations | Chemical Composition Characteristics | Application Range |
|---|---|---|---|
| Carbon Steel | C22, C25, C30 | Low to medium carbon content, suitable for general structures and low-pressure applications | General structural piping, non-high-pressure boiler tubes |
| Low Alloy Steel | S275, S355 | Contains small amounts of alloying elements (such as Cr, Mo, Ni, V) to enhance strength and toughness | High-pressure boiler piping, oil & gas transmission, pressure vessels |
| Special Alloy Steel | Heat-resistant or special steels specified in BS 6323 | Designed for high temperature, high pressure, and corrosion resistance | High-temperature steam boilers, chemical pressure pipelines |
III. BS 6323 Mechanical Properties of Hot-Rolled Steel Tubes
| Steel Grade | Yield Strength σy (MPa) | Tensile Strength σu (MPa) | Elongation A5 (%) | Remarks |
|---|---|---|---|---|
| C22 | 210 – 280 | 340 – 430 | ≥24 | Carbon steel, suitable for low-pressure structural pipes |
| C25 | 240 – 300 | 360 – 460 | ≥22 | Carbon steel, suitable for general structural pipes |
| C30 | 250 – 310 | 400 – 500 | ≥20 | Carbon steel, higher strength structural pipes |
| S275 | 275 – 325 | 430 – 560 | ≥20 | Low alloy steel, suitable for medium-pressure pipelines |
| S355 | 355 – 510 | 470 – 630 | ≥20 | Low alloy steel, for high-pressure boiler pipes and structural pipes |
| Other Heat-Resistant / Special Steels | As specified by the relevant grade standard | As specified by the relevant grade standard | ≥16 – 20 | For high-temperature, high-pressure, and chemical application pipelines |
IV. BS 6323 Chemical Composition of Hot-Rolled Steel Tubes
| Steel Grade | C (Carbon) | Mn (Manganese) | P (Phosphorus) | S (Sulfur) | Si (Silicon) | Other Alloying Elements |
|---|---|---|---|---|---|---|
| C22 | ≤0.22% | ≤1.40% | ≤0.035% | ≤0.035% | ≤0.40% | — |
| C25 | ≤0.25% | ≤1.40% | ≤0.035% | ≤0.035% | ≤0.40% | — |
| C30 | ≤0.30% | ≤1.40% | ≤0.035% | ≤0.035% | ≤0.40% | — |
| S275 | ≤0.25% | ≤1.60% | ≤0.035% | ≤0.035% | ≤0.55% | May contain small amounts of Ni, Cr, Mo |
| S355 | ≤0.27% | ≤1.60% | ≤0.035% | ≤0.035% | ≤0.55% | May contain small amounts of Ni, Cr, Mo |
| Special Heat-Resistant / Alloy Steel | As specified by the relevant grade standard | — | — | — | — | Cr, Ni, Mo, V, etc. |
V. BS 6323 Hot Finished Steel Tube: Quick Selection Table + Flowchart
i. Quick Selection Table
| Selection Factors | Parameter Selection / Recommendation | Remarks |
|---|---|---|
| Application Environment | Low-pressure structures / High-pressure boilers / Oil & gas pipelines / High-temperature steam pipelines | Select steel grade based on pressure and temperature |
| Steel Grade / Material | Carbon steel: C22, C25, C30Low alloy steel: S275, S355Special alloy steel | For high-pressure and high-temperature conditions, choose low alloy or heat-resistant steel |
| Outer Diameter | 21.3 mm – 323.9 mm | Select based on flow rate or design requirements |
| Wall Thickness | 2.0 mm – 25.4 mm | Calculated according to working pressure; thicker walls provide higher pressure resistance |
| Length | 5.8 m – 12 m | Custom cut lengths available; consider transportation and installation |
| Surface Treatment | Anti-rust oil / Painting / Hot-dip galvanizing / Polishing | Choose based on storage conditions or project requirements |
| Tolerance | Outer diameter: ±1% or ±0.5 mmWall thickness: ±10%Length: ±5 mm | Ensures installation accuracy |
| Quality Certification | Mill Test Certificate (MTC), inspection reports | Ensures compliance with BS 6323 standard |
| Notes | Confirm grade matches pressure requirements; consider surface protection; ensure suitable cut length for transport | Avoid safety risks and material loss |
ii. Selection Process Flowchart
Application Environment → Steel Grade Selection → Dimension Selection → Wall Thickness Calculation → Surface Treatment → Tolerance Confirmation → Quality Certification → Order Placement
Step-by-Step Guide:
- Application Environment: Define the intended use, pressure, temperature, and corrosive conditions of the pipeline.
- Steel Grade Selection: Choose from C22/C25/C30, S275/S355, or special alloys.
- Outer Diameter Selection: Determine based on flow rate requirements or structural design specifications.
- Wall Thickness Calculation: Calculate the minimum required wall thickness based on the operating pressure and safety factor.
- Surface Treatment: Specify requirements for rust prevention, corrosion protection, or aesthetic finish.
- Tolerance Verification: Ensure that dimensions comply with design and installation requirements.
- Quality Certification: Confirm that the supplier provides Material Test Certificates (MTC) and inspection reports.
- Order Placement: Place the purchase order based on the specified grade, quantity, and length.
