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BAOSTEEL METAL / BRITISH STANDARD REINFORCING STEEL

BS 4449 B500B Rebar

BS 4449:2005+A3:2016 · WELDABLE RIBBED BAR · DUCTILITY CLASS B

500 MPa Yield ClassRm/Re ≥ 1.08Agt ≥ 5.0%Mill Test Documentation
Project reinforcementDiameter-by-diameter quotations
B500B / PROJECT-READY SPECIFICATIONS

Specify the correct British rebar grade for every bar schedule.

Source weldable B500B reinforcing steel for concrete structures and reinforcement fabrication. Check the BS 4449 edition, tensile and ductility criteria, nominal weights, rib identification and required test documentation before placing a bulk order.

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Explore B500B Technical Properties ↓
Bundled hot rolled ribbed B500B reinforcing steel bars in a real industrial yard; clean photograph with no text

Nominal sizes and supply forms are standards-related information, not a confirmation of live B500B inventory. The exact size, mill, certification status and lead time are verified for each enquiry.

8 Million MTActual annual steel output across product categories
1 Million MTCombined regular inventory across product categories
500,000 m²Factory area
1,000+Employees across the company
MATERIAL OVERVIEW

What Is BS 4449 B500B Rebar?

Class B reinforcement combines a characteristic 500 MPa yield strength with defined ductility and weldability controls.

British-Standard Ribbed Reinforcement

BS 4449 B500B is weldable, deformed reinforcing steel specified for concrete reinforcement. Its current British specification is BS 4449:2005+A3:2016, covering bar, coil and decoiled product. The standard defines B500A, B500B and B500C as separate ductility classes with the same 500 MPa characteristic yield strength.

Specification first: Confirm the exact BS 4449 edition shown on the approved structural drawings. Bar sizes, intended fabrication route, lot testing and third-party certification requirements should be stated in the purchase order.

Three Essential B500B Values

Choose B500B by its specified strength and ductility properties, not only its nominal diameter or the generic phrase “Grade 500 rebar.”

500 MPaCharacteristic yield strength
≥1.08Characteristic tensile/yield ratio
≥5.0%Total elongation at maximum force, Agt
Need B500B for a specific bar-bending schedule?

Send the schedule and inspection requirements with diameter, length and tonnage on separate lines.

ORDERING SPECIFICATIONS

BS 4449 B500B Rebar Specifications

Use the full grade, British Standard edition and traceable inspection requirements when preparing a purchase order.

Procurement fieldBS 4449 B500B specification
ProductWeldable ribbed reinforcing steel for concrete reinforcement
British standardBS 4449:2005+A3:2016
Steel gradeB500B — characteristic yield 500 MPa, ductility class B
Characteristic tensile ratioRm/Re ≥ 1.08
Characteristic total elongationAgt ≥ 5.0%
Yield-strength upper limitAbsolute permissible maximum 650 MPa; conformity assessment follows BS 4449
Product formsStraight ribbed bars, coils and decoiled product as applicable
Example nominal sizesØ6, 8, 10, 12, 16, 20, 25, 32, 40 and 50 mm; verify ordered sizes
Length optionsAgreed commercial lengths or cut lengths; actual availability is confirmed
SurfaceHot-rolled ribbed geometry meeting the declared grade and bonding requirements
Chemical controlsHeat/product analysis limits including C, P, S, Cu, N and CEV
TestsTensile strength, strength ratio, Agt, rebend, nominal mass, rib geometry
DocumentsMill test certificate, heat/batch traceability, optional third-party certification if verified
Fabrication referenceBS 8666:2020 where project bar scheduling, cutting and bending are required
Quote basisGrade, diameter, lengths, tonnage, project documentation, destination and trade terms

What to Include in Your RFQ

  • State B500B to BS 4449:2005+A3:2016 and confirm the project acceptance basis.
  • List nominal diameter, straight or decoiled form, exact lengths and total pieces or metric tons.
  • Provide the bending schedule or BS 8666 shape codes if fabrication is required.
  • Specify MTC, heat identification, any approved supplier scheme, and third-party inspection where required.
  • Provide destination port, Incoterms, target delivery and packing restrictions.
Project approval: Procurement to an applicable material standard does not establish acceptance by every project or authority. Confirm any required CARES or other certification for the specific producer and shipment before ordering.
Close-up of B500B reinforcing bar longitudinal and transverse ribs for British Standard steel grade identification
DIMENSIONS & NOMINAL MASS

B500B Rebar Size & Weight Chart

Metric diameter-to-weight references support bill-of-material checks, packing calculations and quantity-based enquiries.

Nominal diameter (mm)Nominal cross-section (mm²)Nominal mass (kg/m)12 m bar (kg)*Availability
Ø628.30.2222.664Confirm per-size supply
Ø850.30.3954.740Confirm per-size supply
Ø1078.50.6177.404Confirm per-size supply
Ø12113.10.88810.656Confirm per-size supply
Ø16201.11.57918.948Confirm per-size supply
Ø20314.22.46629.592Confirm per-size supply
Ø25490.93.85446.248Confirm per-size supply
Ø32804.26.31375.756Confirm per-size supply
Ø401,256.69.864118.368Confirm per-size supply
Ø501,963.515.413184.956Confirm per-size supply
Nominal mass: Values are rounded from the nominal bar area using 7,850 kg/m³ and published BS reinforcing-bar weight references. A 12 m mass is an arithmetic example, not a stocked length. Actual accepted mass and dimensional tolerances follow the contract and applicable BS 4449 tables.
Buying several diameters in one shipment?

Provide a size-by-size schedule so bar counts, nominal tonnage and bundle quantities can be checked.

GRADE 500 / DUCTILITY CLASS B

B500B Mechanical Properties & Ductility

The characteristic yield strength is the same as B500C, but the specified ratio and elongation requirements differ.

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Mechanical propertySymbolB500B requirementTest and procurement note
Characteristic yield strengthRe500 MPaCharacteristic strength; test result evaluation follows the statistical conformity scheme in BS 4449.
Absolute maximum yield strengthRe650 MPaLimit stated in BS 4449; do not present 500–650 MPa as a guaranteed test range for every bar.
Tensile / yield strength ratioRm / Re≥1.08Characteristic ratio; calculate from corresponding actual tensile and yield test values.
Total elongation at maximum forceAgt≥5.0%Characteristic ductility requirement for B500B.
Absolute individual-test thresholdsConformity assessmentPer standard tablesBS 4449 distinguishes characteristic requirements from limits used in individual-test acceptance.
Test basisTensile testingBS EN ISO 15630-1Include applicable test method, sample identification and lot/heat traceability on quality records.
How to read these values: Characteristic values are used for long-term conformity and are not necessarily identical to every individual specimen acceptance threshold. Actual tested strengths and elongation should be checked on the supplied lot record.
500 MPa

Characteristic yield

650 MPa

Absolute yield upper limit

≥1.08

Tensile / yield ratio

≥5%

Total elongation Agt

Need mechanical-property verification?

Include the lot certificate and required sampling or independent inspection in the quotation scope.

WELDABILITY & CHEMISTRY

B500B Chemical Composition & Carbon Equivalent

BS 4449 sets composition limits for cast analysis and product analysis, including carbon equivalent to support weldability control.

Maximum Chemical Contents (% by Mass)

ElementCast analysis max.Product analysis max.
Carbon (C)0.22%0.24%
Phosphorus (P)0.050%0.055%
Sulphur (S)0.050%0.055%
Copper (Cu)0.80%0.85%
Nitrogen (N)0.012%0.014%
Carbon equivalent (Ceq)0.50%0.52%
The standard includes limited compositional exceptions, such as conditional carbon adjustments and allowances for nitrogen-binding elements. Use the complete contractual standard for acceptance, rather than applying this summary table alone.

Carbon Equivalent & Welding Planning

Carbon equivalent helps assess the influence of alloying elements on weldability. For B500B, the cast-analysis limit is 0.50%, while product-analysis limit is 0.52%, subject to the standard provisions.

Ceq = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15
  • Request cast and product analysis as specified for the contract.
  • Confirm the weld type, joint design and fabrication plan with the project engineer.
  • Follow a qualified welding procedure and relevant requirements such as BS EN ISO 17660 where applicable.
  • Check any mandated third-party approval rather than assuming all B500B shipments have the same certificate.
RIB GEOMETRY, BENDING & ID

B500B Rib Pattern, Rebend Test & Identification

Inspect rolled ribs, the grade-identification arrangement and the required bending or rebending performance.

Rib Geometry & Traceable Marking

BS 4449 differentiates reinforcing grades through rib arrangements. B500B typically uses opposing transverse-rib inclination in the relevant rib series. The manufacturer identification is provided using the standard identification scheme; reconcile the bar markings with bundle tags and certificates.

B500C distinction: B500C has an additional alternating rib-angle pattern in each rib series. Do not use generic embossed numbers or appearance alone to identify the exact grade.
Naturally photographed ribbed rebar with B500B-type opposing transverse rib geometry, no printed overlays

Bend and Rebend Verification

Rebend performance is tested using the appropriate British Standard and product-specific mandrel size; the commonly cited BS 4449 setup includes bending to 90° then rebending by at least 20°, with nominal mandrel diameter linked to bar size.

  • Check the actual contracted edition and diameter-dependent mandrel requirement.
  • Match the rebend test record to the same heat or test lot.
  • Confirm bar scheduling, bending radii and cut tolerances separately against BS 8666:2020 when fabrication is requested.
Require marked bars and test records?

Add rib marking, heat traceability and rebend acceptance to your material inspection checklist.

SUPPLY FORMATS

Straight, Coiled & Decoiled B500B Steel Rebar

Material form, straightening route and length tolerance affect final acceptance and handling requirements.

Full-length bundles of B500B-type ribbed reinforcement stored in an industrial steel yard

Straight Deformed Bars

For construction sites and stockists ordering full commercial lengths, straight ribbed bars can be quoted by diameter and bundle size.

Real industrial coils of ribbed reinforcing steel for automated handling

Coiled Reinforcement

Coils may be suitable for eligible nominal sizes and processing lines. State the grade, diameter, coil unit and processing requirements.

Straightened and cut ribbed steel reinforcing bars arranged by length for processing

Decoiled / Cut-to-Length

Where available, decoiled and cut bars can match fabrication schedules. Confirm residual strength and bend-test acceptance after processing.

Format availability is grade-, diameter-, mill- and destination-dependent. Any fabrication plan must preserve the agreed B500B mechanical performance and traceability.
Calculate Theoretical Mass ↗Check Documentation ↗
CONSTRUCTION APPLICATIONS

Where B500B Reinforcing Steel Is Used

B500B is selected by the engineer’s specification, ductility class, bending schedule and required certification—not by strength alone.

Authentic reinforced concrete site with tied ribbed steel reinforcement cages for beam and slab construction
FOUNDATIONS

Footings & Raft Slabs

Used as specified reinforcement where drawings call for B500B.

FLOOR SYSTEMS

Reinforced Concrete Slabs

Bars and shaped components for suspended and ground-supported slab reinforcement.

FRAMES

Beams & Columns

Main and supplementary reinforcement in designed concrete frames.

CIVIL WORKS

Retaining Structures

Specified reinforcing bars for walls and ground-retaining concrete.

FABRICATION

Cut & Bent Reinforcement

Bending-schedule items for approved fabricators and distribution.

DISTRIBUTION

Project & Merchant Stock

Repeat-diameter supply for qualified procurement channels.

BRITISH STANDARD GRADES

B500B vs B500C vs B500A Rebar

All three British Standard grades have 500 MPa characteristic yield strength, but the ductility classes are not interchangeable.

GradeCharacteristic yieldRm/ReAgtSelection note
B500A500 MPa≥1.05≥2.5%Lower ductility class; small-diameter exceptions apply.
B500B500 MPa≥1.08≥5.0%Class B, the focus of this page.
B500C500 MPa≥1.15 and <1.35≥7.5%Higher ductility class; different acceptance and rib identification.
Design check: A demand for B500C cannot automatically be satisfied with B500B. Confirm the permitted reinforcement class under the structural design and any national annex.
NEXT PRODUCT

BS 4449 B500C Rebar

Class C ductility: stronger deformation capacity controls and a separate grade-identification rib pattern.

View B500C Rebar ↗
ALTERNATIVE STANDARDS

ASTM & GB Rebar

Different standards use different grading, sampling and acceptance rules; substitutions require technical review.

Explore ASTM Rebar ↗
WHY BAOSTEEL METAL

Factory-Based Rebar Procurement Support

Supplier evaluation begins with the right grade and test documentation, followed by commercial and delivery terms.

01

Production at Scale

8 million metric tons of annual steel output across categories support factory-based steel supply.

02

Inventory Coordination

1 million metric tons of combined regular inventory across categories enables specification-led stock checks.

03

Material Verification

Confirm heat identification, chemical composition, tensile results, rebend and certificates for the order.

04

Export Preparation

Clarify bundle marks, packing, port routing, shipment documents and contractual delivery terms.

Factory area: 500,000 m²; workforce: 1,000+ employees. Company-scale figures describe total operations and do not imply B500B-specific inventory or immediate shipment.
THEORETICAL TONNAGE

B500B Rebar Weight Calculator

Estimate shipment tonnage using the published nominal mass per metre for each British Standard rebar diameter.

Enter Your Steel Bar Schedule

2.959 MTEstimated total theoretical weight
29.592 kgEstimated mass per bar
100 barsPieces entered

Calculation Basis

Calculate theoretical steel mass from the bar's nominal kg/m, length and number of pieces. Using nominal mass avoids treating the rib-to-rib outside diameter as a smooth round bar.

Total MT = nominal kg/m × length (m) × quantity ÷ 1,000

For Ø20 mm rebar at 2.466 kg/m, 12 m length and 100 bars, the estimated weight is 2.9592 metric tons (displayed as 2.959 MT).

This is a procurement estimate. Final billed mass may be determined by actual weighed mass, contractual tolerance and agreed basis of sale.

View Diameter Weight Table ↗
MANUFACTURING & HANDLING

B500B Rebar Production and Supply Control

Procurement checks cover steelmaking traceability, bar rolling, rib formation and the agreed material testing route.

Authentic steel rolling mill producing ribbed reinforcing bars with steel machinery and industrial lighting
ROLLING & PROCESS CONTROL

From nominated grade to traceable finished bundles.

For B500B orders, confirm which mill and process route are proposed, how the manufacturer controls product grade and dimensions, and which acceptance test records will accompany the consignment.

  • Review the ordered standard and ductility class.
  • Confirm heat and lot identification from rolling through dispatch.
  • Check tensile ratio, Agt, rebend, rib geometry and nominal mass.
  • Verify certification and inspection status against destination requirements.
AVAILABILITY BY DIAMETER

Check B500B Rebar Sizes and Lead Time

Stock and production are checked against the actual diameter-by-diameter requirement; company inventory is not specific to B500B.

ORDER-SPECIFIC AVAILABILITY

Match supply to your construction schedule.

Share a single purchase schedule with bar diameters, planned lengths, total weight, packaging units and destination. We can then assess available mill supply, suitable fabrication routes and quality document requirements for the requested material.

  • Straight or coil form and any decoiling/straightening requirements.
  • Combined shipment quantities for several diameters.
  • Target handover date, port and trade terms.
  • Certificate and project approval prerequisites.
Ribbed steel reinforcement organized by diameter and tagged bundles in an industrial warehouse
CHEMISTRY · MECHANICAL TESTING · TRACEABILITY

B500B Quality Control & Mill Test Certificates

Every project enquiry should identify the required material standard, acceptance method and documentary evidence.

What to Inspect

  • Material identity: BS 4449 B500B, producer and test lot.
  • Cast/product analysis and carbon equivalent with order-linked values.
  • Yield and tensile results, ratio, Agt and any relevant statistical acceptance record.
  • Rebend result and diameter-related mandrel setting.
  • Nominal mass, rib layout, diameter and marking.
  • Bundle/heat traceability and approved certification where explicitly requested.
An EN 10204 type 3.1 inspection certificate or other requested document format must be agreed for the order; certification by CARES or any similar body must be checked for the actual producer and product scope.

Testing & Documentation

For B500B, the buyer should verify the declared British Standard edition and actual inspection evidence. Third-party inspection and test witnessing can be scoped in the contract, rather than treated as automatically included.

Industrial quality engineer measuring ribbed steel reinforcing bar dimensions and reviewing tensile-test report, no logos
CUTTING & BAR BENDING

Optional Cut Lengths and Fabrication Scheduling

Provide the approved bending schedule when prefabricated reinforcing components are required.

01 / STRAIGHT LENGTHS

Saw or Shear Cutting

Confirm cut lengths, tolerances, end conditions and bundle marking before production.

02 / SHAPED COMPONENTS

BS 8666 Bar Schedules

Where arranged, specify project shape codes, bending dimensions and bend radii to BS 8666:2020.

03 / PROJECT CONTROL

Fabrication Quality

Agree bend-test relevance, grade traceability and packing of cut-and-bent components.

Cutting or bending services are optional and subject to the mill, contractor, selected size and confirmed fabrication capability. Structural bending and welding always follow engineer-approved procedures and relevant project requirements.
Have a BS 8666 bar bending schedule?

Send it with the relevant material grade and documentary requirements so feasibility can be checked.

BUNDLING & EXPORT DELIVERY

Packaging B500B Rebar for Shipment

Prepare bar bundles and supporting documents so diameter, grade, quantity and traceability remain clear through transport.

Neatly strapped steel reinforcing bar bundles ready for export loading with realistic plain identification tags
PACKING & DISPATCH

Simple, traceable packing for bulk steel.

Common arrangements include secured rebar bundles with batch/grade and diameter identification, together with packing records and shipping documents as agreed in the contract.

  • Confirm bundle weight and lifting constraints.
  • Align markings and mill test documents to the shipping list.
  • Specify handling or corrosion protection needs for the route.
  • Confirm FOB, CFR or CIF and agreed loading/discharge conditions.
PROCUREMENT FAQ

BS 4449 B500B Rebar Questions

Answers for structural contractors, rebar fabricators, distributors and international sourcing teams.

What is BS 4449 B500B rebar?

B500B is weldable ribbed steel for concrete reinforcement to BS 4449:2005+A3:2016, with 500 MPa characteristic yield strength and class B ductility.

Which version of BS 4449 is current?

BS 4449:2005+A3:2016 is the current published British Standard amendment version identified by BSI. Contracts should cite the exact edition.

Is B500B the same as B500C?

No. B500B requires characteristic Rm/Re ≥1.08 and Agt ≥5%; B500C requires Rm/Re ≥1.15 and below 1.35 and Agt ≥7.5%. A design specifying class C needs separate approval before substitution.

Is the minimum tensile strength of B500B always 540 MPa?

The key standard performance is a characteristic tensile-to-yield ratio ≥1.08 with characteristic yield 500 MPa. Multiplying them gives 540 MPa as a nominal design comparison, but conformity depends on measured paired test values and the relevant evaluation rules.

What is B500B maximum yield strength?

BS 4449 specifies an absolute maximum permissible yield strength of 650 MPa; characteristic and individual acceptance values must be interpreted under the standard.

What are the BS 4449 rebar sizes?

Common metric nominal diameters include 6, 8, 10, 12, 16, 20, 25, 32, 40 and 50 mm. Confirm the selected size and supply form for the mill and order.

How heavy is a 20 mm B500B bar?

The typical nominal weight is about 2.466 kg/m. A 12 m bar is about 29.592 kg; 100 such bars are approximately 2.9592 metric tons before contractual weighing or tolerance.

Can B500B be supplied as coil or decoiled bars?

BS 4449 covers straight bar, coil and decoiled products. Coil eligibility, actual diameter, and post-decoiling performance must be confirmed for the order.

Which chemical limits affect B500B weldability?

Typical cast-analysis maxima include C 0.22%, P 0.05%, S 0.05%, Cu 0.80%, N 0.012% and Ceq 0.50%, subject to the complete standard exceptions.

Does B500B automatically come with UK CARES approval?

No. Any required certification or approved-mill status must be verified for the actual manufacturer, product scope, mill and shipment; an MTC alone does not prove third-party certification.

What standard governs cut and bent reinforcement?

BS 8666:2020 covers scheduling, dimensioning, bending and cutting of reinforcement. The steel material remains subject to its specified product standard.

How can we request a B500B quotation?

Send BS 4449:2005+A3:2016, ductility class B500B, bar diameters and lengths, weight or piece counts, any fabrication schedule, document requirements, destination and Incoterms.

BAOSTEEL METAL / BRITISH STANDARD REBAR

Request a BS 4449 B500B Rebar Quote

Send the BS 4449 edition, B500B grade, nominal diameters, individual lengths and quantities, fabrication schedule and certification needs. We will assess the order-specific supply and delivery basis.

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