BS 6744 Grade 1.4404 Stainless Steel Rebar
The Globally Trusted Low-Carbon Solution for Welded Coastal Infrastructure
As a leading global manufacturer and exporter, Hunan Fushun Metal Co., Ltd. presents our superior stainless steel reinforcing bars, manufactured to meet the stringent requirements of BS 6744. Our Grade 1.4404 rebar is the low-carbon evolution of the classic 1.4401, delivering exceptional corrosion resistance, best-in-class weldability, and long-term structural integrity. As the world’s most widely specified molybdenum-bearing austenitic stainless steel for concrete reinforcement, 1.4404 is the proven choice for critical infrastructure in coastal, marine, and chemical exposure conditions.
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 1.4404 (commonly known as 316L), 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 1.4404 bar is fully traceable with a documented metallurgical history, a critical requirement of the standard.
1. Chemical Composition (Cast Analysis)
Grade 1.4404 is an extra-low-carbon (max 0.03%) austenitic stainless steel with a deliberate Molybdenum (Mo) addition, specifically engineered to resist pitting corrosion in chloride-rich environments. The ultra-low carbon content minimizes the risk of intergranular corrosion after welding, making it the ideal choice for fabricated reinforcement cages. According to BS 6744 Table 5, 1.4404 is listed among the “Alloys used for corrosion resistance to chloride ingress in concrete.” 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) | 2.0 |
| Sulphur (S) | 0.030 |
| Chromium (Cr) | 16.5 – 18.5 |
| Nickel (Ni) | 10.0 – 13.0 |
| Molybdenum (Mo) | 2.0 – 2.5 |
| Phosphorus (P) | 0.045 |
| Nitrogen (N) | ≤ 0.11 |
Note: This composition is in strict adherence to BS 6744, Table 5 for the 1.4404 designation. The 2.0–2.5% molybdenum addition provides a significant upgrade in chloride pitting resistance compared to standard austenitic grades.
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
The carefully controlled manufacturing process guarantees that the product is free from detrimental phases and intergranular corrosion, as verified by our rigorous testing protocol.
3. Dimensions, Mass, and Tolerances
We manufacture the Grade 1.4404 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 with Mo addition” steels, as listed in Table 3. For example, a 20 mm bar has a nominal mass of 2.514 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 continuously achieve the mechanical properties for Ductility Class B as defined in BS 6744, Table 8.
| Property | Requirement |
|---|---|
| Designation | BS 6744 – 1.4404, 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 excellent dynamic load performance |
The austenitic structure of 1.4404 provides outstanding ductility, making it ideal for applications in seismic zones or structures subject to high dynamic loading.
Ready to specify the world’s most trusted low-carbon stainless steel rebar for your coastal 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 (1.4404)
- 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.
- Intergranular corrosion test results (one test per batch), in accordance with BS EN ISO 3651-2.
- Confirmation of durability class and the manufacturer’s rolled-on mark.
- A statement of conformity to BS 6744.
Note: As an austenitic grade, 1.4404 is not subject to the mandatory Charpy impact testing required for duplex designations under Clause 12.12.1.
Frequently Asked Questions
What is the key advantage of 1.4404 over 1.4401, and why is it the preferred grade for welded reinforcement?
The critical difference is the carbon content. Grade 1.4404 has a maximum carbon of 0.03%, compared to 0.07% for 1.4401. According to BS 6744 Table 5, this extra-low-carbon composition minimizes the risk of chromium carbide precipitation during welding, which can lead to intergranular corrosion. This makes 1.4404 the material of choice when reinforcement cages or assemblies require on-site or factory welding.
Why is Molybdenum so important in this grade?
Molybdenum is the key alloying element that dramatically improves a stainless steel’s resistance to pitting and crevice corrosion, particularly in the presence of chlorides. The 2.0–2.5% Molybdenum content in 1.4404, as specified in BS 6744 Table 5, places it significantly above standard austenitic grades like 1.4301 or 1.4311 for use in coastal structures, bridge decks in cold regions where de-icing salts are used, and marine environments.
Is 1.4404 magnetic?
No. Like all standard austenitic stainless steels, 1.4404 has a very low magnetic permeability in the annealed condition. While it is not explicitly listed under “Alloys used for low magnetic permeability” in BS 6744 Table 5, its austenitic microstructure means it remains practically non-magnetic, which can be a critical requirement for certain applications such as near sensitive scientific instruments.
What are the typical applications for 1.4404 rebar?
Grade 1.4404 is the global workhorse for durable concrete structures. Its primary market is coastal and marine infrastructure, including sea walls, quay decks, bridge support columns in tidal zones, and ferry terminals. It is also extensively used in structures exposed to de-icing salts, such as bridge parapets and highway infrastructure, and in industrial facilities like chemical and water treatment plants.
Can FUSHUN METAL supply 1.4404 rebar in complex fabricated shapes?
Yes, absolutely. Per BS 6744, Clause 11, our ribbed stainless steel bars can be supplied straight, in coils, or fabricated in accordance with BS 8666. The excellent formability and weldability of the low-carbon 1.4404 grade make it an ideal material for prefabricated cages, complex bent shapes, and custom assemblies, all delivered to your site with full traceability from cast to final component.
Extend the Service Life of Your Coastal Infrastructure
Contact FUSHUN METAL today to discover how our BS 6744 Grade 1.4404 stainless steel reinforcement can provide a trusted, cost-effective solution for the extended service life of your coastal or industrial infrastructure projects.
Specify the global standard. Low-carbon 316L rebar with full mill certification, weldability assurance, and worldwide logistics.
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