BS 6744 Grade 1.4501 Stainless Steel Rebar
Ultimate Corrosion Resistance for the World’s Most Aggressive Environments
As a leading global manufacturer and exporter, Hunan Fushun Metal Co., Ltd. presents our flagship super duplex stainless steel reinforcing bars, manufactured to meet the stringent requirements of BS 6744. Our Grade 1.4501 rebar represents the pinnacle of corrosion-resistant concrete reinforcement, delivering unmatched resistance to pitting, crevice corrosion, and stress corrosion cracking in the most extreme chloride-laden and chemically aggressive environments. When only the ultimate protection will suffice for a multi-generational design life, FUSHUN METAL provides the definitive solution.
With deep expertise across specialty steel products, including alloy structural steel, nickel-based alloys, and tool steel, and full compliance with international benchmarks like ASTM, EN, DIN, and JIS, we guarantee that our BS 6744-compliant reinforcement bars offer unparalleled quality and performance. This introduction focuses on our ribbed stainless steel bar, steel designation 1.4501 (super duplex), in strength grade 500.
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Technical Specifications & Compliance
Our reinforcement bars are produced and tested strictly in accordance with BS 6744, which specifies the requirements for solid stainless steel bars used for concrete reinforcement. This standard is applicable to ribbed bars in grade 500, where ribs are formed by cold working or hot rolling processes. FUSHUN METAL’s Grade 1.4501 bar is fully traceable with a documented metallurgical history, a critical requirement of the standard.
1. Chemical Composition (Cast Analysis)
Grade 1.4501 is a super duplex stainless steel with a highly engineered composition designed for maximum resistance to the most aggressive corrosion challenges. Featuring significantly elevated levels of Chromium, Nickel, Molybdenum, and Nitrogen, this alloy far exceeds the performance of standard duplex grades. According to BS 6744 Table 5, 1.4501 is listed under the “Alloys used for special applications” category, where specialist corrosion advice might be required to specify. The precise cast analysis is tightly controlled within the following limits:
| Element | Requirement (% by mass, max unless range given) |
|---|---|
| Carbon (C) | 0.03 |
| Silicon (Si) | 1.0 |
| Manganese (Mn) | 1.0 |
| Sulphur (S) | 0.015 |
| Chromium (Cr) | 24.0 – 26.0 |
| Nickel (Ni) | 6.0 – 8.0 |
| Molybdenum (Mo) | 3.0 – 4.0 |
| Phosphorus (P) | 0.035 |
| Nitrogen (N) | 0.20 – 0.30 |
Note: This composition is in strict adherence to BS 6744, Table 5 for the 1.4501 designation. The exceptionally high chromium (24.0–26.0%) and molybdenum (3.0–4.0%) content, combined with a substantial nitrogen addition (0.20–0.30%), provides the highest level of pitting and crevice corrosion resistance of any grade listed in the standard.
2. Heat Treatment Condition
Our ribbed stainless steel bars are supplied in one of the following conditions as per BS 6744, Clause 11, ensuring optimal mechanical properties and surface finish:
- Hot rolled and descaled
- Hot rolled, descaled, and decooled
Per BS 6744, Clause 12.12.1, the 1.4501 super duplex grade undergoes additional rigorous testing to verify the absence of detrimental metallurgical phases in the finished condition. The results are quoted directly on the test certificate, providing complete assurance of microstructural integrity for this highly alloyed material.
3. Dimensions, Mass, and Tolerances
We manufacture the Grade 1.4501 rebar in a wide range of standard diameters, from 6 mm to 50 mm, in full compliance with the standard. The dimensional characteristics are precisely controlled to ensure a perfect bond with concrete.
Standard Diameters
The following nominal diameters are available as standard for the 500 strength grade, as specified in BS 6744, Clause 5 and Table 2:
| Grade | Nominal Diameters (mm) |
|---|---|
| 500 | 6, 7, 8, 10, 12, 14, 16, 20, 25, 32, 40, 50 |
Note: Non-standard diameters may also be available upon request.
- Nominal Length
- Agreed upon at the time of order, with a standard permissible deviation of +100/0 mm or as per BS 8666.
- Nominal Mass per Meter Run
- Calculated according to BS EN ISO 15630, our bars strictly conform to the specified nominal mass per meter for austenitic-ferritic (duplex) steels. For example, a 20 mm bar has a nominal mass of 2.451 kg/m.
- Tolerances on Mass
- Stringent tolerances are applied, ranging from ±9.0% for a 6 mm bar to ±4.5% for bars over 12 mm in diameter.
4. Grade & Mechanical Properties (Strength Level 500, Ductility Class B)
Our reinforcing bars are designated as strength grade 500 and consistently surpass the mechanical properties for Ductility Class B as defined in BS 6744, Table 8.
| Property | Requirement |
|---|---|
| Designation | BS 6744 – 1.4501, B500B |
| Characteristic Yield Strength (fyk) | 500 MPa |
| 0.2% Proof Strength (Rp0.2) | 500 MPa minimum |
| Tensile Strength (Rm) | Meets the minimum value for the stress ratio |
| Stress Ratio (Rm/Rp0.2) | ≥ 1.08 |
| Total Elongation at Max Force (Agt) | ≥ 5.0% |
| Elongation After Fracture (A5) | ≥ 14% |
| Bendability | Passes 180° bend test around a former of max diameter specified (e.g., 4d for d≤16 mm, 7d for d>16 mm) |
| Fatigue Strength | Withstands 5 × 106 cycles of stress at a stress ratio of 0.2 without fracture, ensuring superior dynamic load performance |
Note: While the 500 MPa minimum requirement applies, the super duplex microstructure of 1.4501 typically delivers significantly higher yield strength, offering designers an exceptional margin of safety for the most critical structural applications.
Ready to specify the ultimate corrosion-resistant super duplex rebar for your most demanding project?
Request a Quote5. Surface Geometry & Bonding
Ensuring a strong mechanical interlock with concrete is paramount. Our bars feature rows of crescent-shaped transverse ribs that meet the geometric criteria of BS 6744, Clause 10:
- Relative Rib Area (fR): Exceeds the minimum relative rib area (fRmin) specified in Table 6, which is the ruling criterion for bond performance.
- Rib Flank Inclination (α): Measured at ≥ 45°, ensuring effective load transfer without splitting the concrete cover.
- Transverse Rib Projection: Extends over at least 80% of the bar’s periphery.
These geometric properties are measured and verified in accordance with BS EN ISO 15630-1.
6. Packaging and Product Identification
Every product from FUSHUN METAL is meticulously packaged and labelled to guarantee complete traceability and compliance.
- Product Marking
- Each bar is identified by rolled-on legible marks on the surface at intervals not greater than 1.5 meters, identifying the manufacturer as specified by the standard.
- Bundle / Coil Labelling
- Each bundle or coil is firmly attached with a durable label containing all the mandatory information per BS 6744, Clause 13.2:
- Standard Reference (BS 6744)
- Steel Designation (1.4501)
- Nominal Diameter
- Strength Grade (500)
- Ductility Class (B)
- Durability Class
- Cast Number and Batch Reference
- Manufacturer’s Name (FUSHUN METAL)
7. Inspection & Test Report
Quality assurance is non-negotiable. Our products are tested at a frequency of one test per ten tonnes from each production batch. Every shipment is accompanied by a detailed test certificate as per Clause 12.3, which includes:
- The complete cast analysis for all specified elements.
- Results of the tensile test (including effective cross-sectional area), confirming 0.2% proof strength, stress ratio, and elongation properties.
- Results of the bend test.
- Charpy impact test results (three tests per batch, for diameters 16 mm and above), in accordance with BS EN ISO 148-1.
- Intergranular corrosion test results (one test per batch), in accordance with BS EN ISO 3651-2, confirming the absence of detrimental metallurgical phases.
- Confirmation of durability class and the manufacturer’s rolled-on mark.
- A statement of conformity to BS 6744.
Frequently Asked Questions
What makes Grade 1.4501 the ultimate choice within BS 6744 for corrosion resistance?
Grade 1.4501 is classified by BS 6744 Table 5 as an “Alloy used for special applications,” and its chemical composition justifies this designation. It features 24.0–26.0% Chromium, 3.0–4.0% Molybdenum, and 0.20–0.30% Nitrogen—the highest alloy content of any grade in the standard. This composition delivers a PREN typically exceeding 40, making it suitable for the most aggressive environments where even 1.4462 would be insufficient, such as warm, high-salinity seawater or hot chemical process streams.
What are the mandatory supplementary tests for 1.4501, and why are they critical?
In accordance with BS 6744, Clause 12.12.1, the 1.4501 super duplex designation is explicitly listed as requiring additional testing to “ensure the absence of detrimental metallurgical phases in the finished condition.” For every batch, FUSHUN METAL performs and certifies both the Charpy V-notch impact test (per BS EN ISO 148-1) and the intergranular corrosion test (per BS EN ISO 3651-2). These tests are vital for highly alloyed duplex materials to confirm that manufacturing processes have not created harmful phases like sigma or chi phase, which could severely compromise both toughness and corrosion resistance.
When would I specify 1.4501 over a premium austenitic grade like 1.4429?
You would select 1.4501 when the project demands both the absolute highest level of corrosion resistance and significantly higher mechanical strength. While 1.4429 is an excellent high-end austenitic, 1.4501’s super duplex microstructure delivers a much greater yield strength, allowing for either higher load capacity or potential material optimization. It is the definitive choice for structures in exceptionally aggressive environments such as warm seawater outfalls, hot brine containment, and offshore wind turbine foundations.
Is 1.4501 rebar magnetic?
Yes. As a super duplex stainless steel with a mixed austenitic-ferritic microstructure, 1.4501 is ferromagnetic. This differentiates it from fully austenitic grades. The magnetic characteristic can be a practical advantage on construction sites for handling and lifting, but it must be considered during design if non-magnetic properties are a required specification, as per guidance in BS 6744 Annex C.
Can FUSHUN METAL supply 1.4501 fabricated to BS 8666, given its high strength?
Yes, absolutely. Per BS 6744, Clause 11, our stainless steel bars can be supplied fabricated in accordance with BS 8666. Our advanced processing facilities are fully equipped to handle super duplex materials, managing the higher bending forces required to produce precise reinforcing cages and complex bent shapes. We deliver these ready-to-install components with full traceability from the original cast through to the final fabricated assembly, ensuring quality compliance at every step.
Protect Your Most Critical Assets with Super Duplex Reinforcement
Contact FUSHUN METAL today to discuss how our BS 6744 Grade 1.4501 super duplex stainless steel reinforcement can provide the ultimate lifetime protection for your most critical assets in the world’s most corrosive environments.
Specify the flagship. Super duplex 1.4501 rebar with highest alloy content, full supplementary testing, and dedicated global project logistics.
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