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API 5L Grade B Threaded Flange Supplier, Stockist & Exporter in Mumbai, India

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Other API 5L Grade B Products

Threaded Flange in Other Grades

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ISO 9001:2015 • PED 2014/68/EU
NACE MR0175 • EN 10204 3.1 MTC

Table of Contents

  1. Introduction
  2. Chemical Composition
  3. Mechanical Properties
  4. Physical & Thermal Properties
  5. Equivalent Grades
  6. Threaded Flange Details
  7. Manufacturing Process
  8. Sizes & Dimensions
  9. Types Available
  10. Applications
  11. Industries Served
  12. Grade Comparison
  13. Why BB Infras?
  14. Certifications & QC
  15. Export & Packaging
  16. Threaded Flange Marking
  17. Coating Options
  18. Testing Procedure
  19. Storage Guidelines
  20. Downloads
  21. Cities We Supply
  22. Countries We Export
  23. FAQ
  24. People Also Ask
  25. Related Products
Verified by BB Infras Technical Team  •  Regularly reviewed & updated
API 5L Grade B Threaded Flange – Threaded Flange Supplier India, BB Infras Mumbai
API 5L Grade B Threaded Flange – Threaded Flange Supplier India, BB Infras Mumbai API 5L Grade B Threaded Flange – Flange Close-up Detail Weld Neck Flange – Ready Stock BB Infras Blind Flange – Ready Stock BB Infras Steel Flanges & Pipes – BB Infras Mumbai
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MaterialLine Pipe Steel
GradeAPI 5L Grade B / API 5L Gr.B / ISO 3183
StandardAPI 5L Gr.B / ISO 3183
TypeThreaded Flange
Size RangeOD 21.3 mm – 1219 mm; WT SCH 10 to SCH 160
Pressure Class150# – 2500# (ASME B16.5)
FacingRF / FF / RTJ
Dimensional StdASME B16.5 / B16.47
Tensile Strength415 MPa min
Yield Strength245 MPa min
MTCEN 10204 3.1 Mill Test Certificate
MOQ100 kg (standard sizes)

Quick Answers

What is API 5L Grade B Threaded Flange?
A threaded flange manufactured to API 5L Gr.B / ISO 3183. API 5L Grade B is the baseline carbon steel for oil & gas transmission line pipes. It balances weldability with adequate strength for onshore and offshore pipeline systems in moderate-pressure service.
What sizes does BB Infras stock?
BB Infras stocks API 5L Grade B Threaded Flange in sizes OD 21.3 mm – 1219 mm; WT SCH 10 to SCH 160. Same-day quotation from our Mumbai stockyard.
What is the MOQ and delivery time?
MOQ is 100 kg or 1 piece for standard sizes. Standard sizes dispatched within 3–5 business days from our Mumbai stockyard.

API 5L Grade B Threaded Flange – Overview

API 5L Grade B is the baseline carbon steel for oil & gas transmission line pipes. It balances weldability with adequate strength for onshore and offshore pipeline systems in moderate-pressure service.

BB Infras is an established API 5L Grade B Threaded Flange supplier to EPC contractors and pipeline operators across India and the Gulf region. We stock both PSL1 and PSL2 grades; sour-service documentation including HIC and SSC test reports is available on request for critical pipeline applications. API 5L Grade B Threaded Flange is available in pressure classes 150# to 2500# per ASME B16.5 / B16.47, with raised face (RF), flat face (FF) or ring type joint (RTJ) facing options. Custom bore and custom OD flanges are available on order.

API 5L Gr.B / ISO 3183 Line Pipe Steel Sizes: OD 21.3 mm – 1219 mm; WT SCH 10 to SCH 160 EN 10204 3.1 MTC Export Ready

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Chemical Composition of API 5L Grade B

The following table shows the chemical composition per API 5L Gr.B / ISO 3183.

CMnPSSiVNbTi
≤ 0.28≤ 1.20≤ 0.030≤ 0.030≤ 0.45≤ 0.05≤ 0.05≤ 0.04

Mechanical Properties of API 5L Grade B

PropertyValue
Tensile Strength415 MPa min
Yield Strength245 MPa min
Elongation21% min
SMYS35,500 psi / 245 MPa

Physical & Thermal Properties

PropertyValue
Density7.85 g/cm³
Melting Point1420–1530 °C
Thermal Conductivity50 W/m·K
Thermal Expansion11.9 × 10⁻⁶ /°C
Elastic Modulus200 GPa
Specific Heat480 J/kg·K
Electrical Resistivity0.172 μΩ·m

Equivalent Grades of API 5L Grade B

Standard BodyEquivalent Grade
API5L Gr.B
EN ISO 3183L245
ASTMA53 Gr.B / A106 Gr.B
IS1978 Gr.B

Threaded Flange – Product Details

Threaded flanges use NPT or BSP internal threads to connect to threaded pipe ends without welding. Used where welding is impractical (explosive atmospheres, retrofit work) or where the pipe must be removable without cutting.

Applicable Standards: ASME B16.5, ASME B1.20.1 (NPT), BS 21 (BSP)

Manufacturing Process: Forged; bore threaded to ANSI NPT or BSP; face finished RF or FF.

Heat Treatment: Normalise or thermo-mechanical controlled rolling (TMCP).

API 5L Grade B Threaded Flange – Manufacturing Process

Threaded Flange is produced using a controlled sequence of operations to achieve the dimensional and mechanical requirements of API 5L Gr.B / ISO 3183.

Steel Billet
Heating
1050–1200 °C
Die Forging
Heat Treatment
Normalise / Q&T
CNC Machining
Face & bore
Dimensional Inspection
Per ASME B16.5
NDT & Chemical
MTC & Marking
Packing & Dispatch

API 5L Grade B Threaded Flange – Sizes & Dimensions

Size range: OD 21.3 mm – 1219 mm; WT SCH 10 to SCH 160. The following dimensional data covers standard sizes. Non-standard sizes available on request.

NPSThread TypeFlange OD (mm)Bolt Circle (mm)No. Bolts
½"½" NPT9566.54
¾"¾" NPT11382.54
1"1" NPT12585.74
1½"1½" NPT160114.34
2"2" NPT1651274
3"3" NPT210168.34
4"4" NPT2542008

Types of API 5L Grade B Threaded Flange

  • 150# Threaded Flange
  • 300# Threaded Flange
  • 600# Threaded Flange
  • NPT / BSP variants

Applications of API 5L Grade B Threaded Flange

Hazardous area piping (no hot work)
Galvanised piping systems
Compressed air & water service
Temporary process connections
Retrofit and modification work

Industries We Serve

Oil & Gas
Petrochemical
Power Generation
Chemical
Marine & Offshore
Construction
Water & Sewage
Pharmaceutical
Food & Beverage
Automotive
Fertiliser
Cryogenic / LNG

Ready to order API 5L Grade B Threaded Flange?

Stock available in Mumbai. Same-day quotation. Export documentation included.

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API 5L Grade B – Grade Specification

StandardCategory Tensile StrengthYield StrengthElongation
API 5L Gr.B / ISO 3183 ✓ Line Pipe Steel 415 MPa min245 MPa min21% min
API (5L Gr.B) Equivalent See equivalent grades table above
EN ISO 3183 (L245) Equivalent See equivalent grades table above
ASTM (A53 Gr.B / A106 Gr.B) Equivalent See equivalent grades table above
IS (1978 Gr.B) Equivalent See equivalent grades table above

* All values are minimum guaranteed per API 5L Gr.B / ISO 3183. Actual mill certificates may show higher values.

Why Buy API 5L Grade B Threaded Flange from BB Infras?

Ready Stock Large inventory of API 5L Grade B Threaded Flange in popular sizes maintained in our Mumbai warehouse for immediate dispatch.
Certified Material All material supplied with EN 10204 3.1 Mill Test Certificates from NABL-accredited labs. TPI by SGS, BV, TUV on request.
Worldwide Export We export API 5L Grade B Threaded Flange to 80+ countries with complete export documentation — COO, packing list, B/L, fumigation certificates.
Competitive Pricing Direct mill sourcing and bulk buying ensures competitive prices. No middlemen. Transparent pricing with no hidden charges.
Fast Delivery Standard sizes dispatched within 3–5 business days. Custom sizes within 3–4 weeks. Urgent orders accommodated.
Value-Added Services Cut-to-length, bevelling, threading, galvanising, painting, marking & stencilling available in-house.
Technical Support Our metallurgical team assists with grade selection, standard interpretation, and material substitution queries.
MSME Registered Registered MSME supplier. Eligible for GeM portal procurement and government tenders.

Certifications & Quality Inspection

Every API 5L Grade B Threaded Flange supplied by BB Infras undergoes the following quality controls:

ISO 9001:2015 EN 10204 3.1 MTC PED 2014/68/EU NACE MR0175 BIS / IS Marked NABL Lab Reports TPI Available

Quality Inspection Checklist

  • Chemical composition analysis (OES / wet analysis)
  • Mechanical testing: tensile, yield, elongation, impact
  • Dimensional inspection per applicable ASME standard
  • Visual and surface finish inspection
  • Hydrostatic or pneumatic pressure testing
  • Non-Destructive Testing: UT, RT, MT, PT on request
  • Positive Material Identification (PMI) on request

Export Packaging & MOQ

  • Minimum Order Quantity (MOQ): 100 kg or 1 piece (standard sizes); 500 kg for custom sizes
  • Packing for Pipes/Tubes: Bundled with steel strapping, plastic end caps, moisture-proof wrapping
  • Packing for Fittings/Flanges: Wooden box / wooden pallet, plywood case for heavy items
  • Sea Freight: FCL / LCL container, fumigation certificate provided
  • Air Freight: Available for urgent requirements
  • Documents: Commercial Invoice, Packing List, Certificate of Origin, MTC, Bill of Lading, Insurance Certificate
  • Marking: Heat number, grade, size, schedule, standard per ASTM A5.40 / ASME marking requirements

Threaded Flange Marking & Identification

Every API 5L Grade B Threaded Flange supplied by BB Infras is marked per API 5L Gr.B / ISO 3183 and ASME marking requirements. Standard marking sequence:

BB INFRAS | API 5L Gr.B | 150# | 4" | RF | HEAT: XXXXXX
  • Manufacturer name / mark
  • Material specification — API 5L Gr.B
  • Pressure class — 150# / 300# / etc.
  • NPS size
  • Facing type — RF / FF / RTJ
  • Heat / lot number — for MTC traceability

Coating & Surface Finish Options

Coating TypeStandardApplicationLead Time
Mill Finish / Black PaintPer standardGeneral process serviceIn Stock
Yellow Zinc Chromate Primer—Corrosion protection in transitIn Stock
Hot-Dipped Galvanised (HDG)ASTM A123Plumbing & utility service3–5 days
Two-Coat Epoxy Paint—Offshore & chemical plant1–2 weeks

Testing & Inspection Procedure

All API 5L Grade B Threaded Flange supplied by BB Infras undergo a multi-stage inspection and testing process before dispatch:

#Test / InspectionStandard / MethodAcceptance
1Chemical Composition (OES)ASTM E415Per API 5L Gr.B Table 1
2Tensile & Yield StrengthASTM E8≥415 MPa min / ≥245 MPa min
3ElongationASTM E8≥21% min
4Hardness (HB)ASTM E10Per standard max
5Hydrostatic TestAPI 5L Gr.B / ASME B31.3Leak-free at test pressure
6Dimensional InspectionASME B16.5Within tolerance
7Visual & SurfaceASTM A530 / MSS SP-55Free from defects
8Ultrasonic Testing (UT)ASTM E213 (on request)No sub-surface defects
9PMI (XRF)ASTM E1476 (on request)Grade confirmation

Storage & Handling Guidelines

  • Store on wooden dunnage or pipe racks — never directly on concrete to avoid moisture-induced corrosion.
  • Stack with appropriate separators; observe safe stack heights to prevent deformation.
  • Apply plastic end caps or plugs to all open ends to prevent ingress of moisture, dust and insects.
  • Keep material dry and ventilated; store under cover in humid or coastal climates.
  • Use nylon slings or padded lifting hooks — never bare wire rope directly on surface.
  • For long-term storage (>6 months), re-apply protective oil coating or wrap with VCI (Vapour Corrosion Inhibitor) film.
  • Identify items with heat number tags throughout storage for full MTC traceability.

Downloads & Technical Resources

Request product documentation from our technical team. Available on enquiry:

Contact our technical team with your enquiry details and we will share the relevant document within 24 hours.

API 5L Grade B Threaded Flange Supplier in India

BB Infras supplies API 5L Grade B Threaded Flange to customers across India from our Mumbai stockyard. We serve all major industrial hubs — refineries in Jamnagar and Haldia, petrochemical clusters in Dahej and Panipat, shipyards in Kochi and Visakhapatnam, and fabrication workshops across Pune, Rajkot, Surat and Coimbatore — with same-day quotation and fast dispatch.

View all cities we supply ▾
MumbaiDelhi BangaloreChennai HyderabadPune AhmedabadKolkata SuratJaipur RajkotVadodara CoimbatoreNagpur IndoreBhopal LucknowKanpur PatnaBhubaneswar VisakhapatnamKochi ChandigarhLudhiana AmritsarFaridabad GurgaonNoida AgraNashik AurangabadSolapur BhavnagarJamnagar AnkleshwarHaldia MundraParadip

API 5L Grade B Threaded Flange Exporter – Countries We Ship To

BB Infras exports API 5L Grade B Threaded Flange to 80+ countries with complete export documentation — Certificate of Origin, Material Test Certificate, Packing List, Bill of Lading and Fumigation Certificate. We are a trusted exporter to UAE, Saudi Arabia, Qatar, Oman and Kuwait in the Middle East; to Singapore, Malaysia, Indonesia and Vietnam in Southeast Asia; to South Africa, Nigeria and Kenya in Africa; and to the USA, UK, Germany and Netherlands in Europe and North America.

View all export countries ▾
USAUAE Saudi ArabiaQatar KuwaitOman BahrainIraq UKGermany FranceItaly SpainNetherlands BelgiumPoland TurkeyRussia BrazilMexico ArgentinaColombia AustraliaNew Zealand South AfricaNigeria KenyaEgypt MalaysiaSingapore IndonesiaThailand VietnamPhilippines South KoreaJapan BangladeshSri Lanka PakistanCanada NorwaySweden DenmarkSwitzerland AustriaIsrael JordanKazakhstan

Frequently Asked Questions

What is API 5L Grade B Threaded Flange?
API 5L Grade B Threaded Flange is a threaded flange manufactured to the API 5L Gr.B / ISO 3183 specification. API 5L Grade B is the baseline carbon steel for oil & gas transmission line pipes. It balances weldability with adequate strength for onshore and offshore pipeline systems in moderate-pressure service.
What sizes of API 5L Grade B Threaded Flange does BB Infras supply?
BB Infras supplies API 5L Grade B Threaded Flange in the size range OD 21.3 mm – 1219 mm; WT SCH 10 to SCH 160. Special sizes are available on request with 3–4 weeks lead time.
What is the chemical composition of API 5L Grade B?
See the chemical composition table above for the complete element breakdown per the standard.
What is the tensile strength of API 5L Grade B Threaded Flange?
Per API 5L Gr.B / ISO 3183, the minimum tensile strength is 415 MPa min and the yield strength is 245 MPa min.
Do you supply API 5L Grade B Threaded Flange with MTC?
Yes. All products are supplied with EN 10204 3.1 Mill Test Certificates. Third-party inspection by SGS, TUV, BV or Lloyd's is available on request.
What is the equivalent grade of API 5L Grade B?
See the equivalent grades table above for ASTM, EN, DIN, JIS and IS cross-references.
What are the applications of API 5L Grade B Threaded Flange?
API 5L Grade B Threaded Flange is used in: Hazardous area piping (no hot work), Galvanised piping systems, Compressed air & water service, Temporary process connections, Retrofit and modification work.
What is the heat treatment for API 5L Grade B?
Normalise or thermo-mechanical controlled rolling (TMCP).
Can BB Infras export API 5L Grade B Threaded Flange worldwide?
Yes. BB Infras exports to 80+ countries. We provide all export documentation including COO, packing list, bill of lading and fumigation certificates.
What is the minimum order quantity for API 5L Grade B Threaded Flange?
Minimum order quantity is 100 kg or 1 piece for standard sizes. For custom or exotic grades, MOQ may be 500 kg. Contact us for exact pricing.
What schedules or pressure classes are available for API 5L Grade B Threaded Flange?
Pressure classes 150# through 2500# per ASME B16.5 are available. Contact us for exact stock availability.
What coating options are available for API 5L Grade B Threaded Flange?
API 5L Grade B Threaded Flange is available in mill finish (black), hot-dipped galvanised (HDG), oil-coated, FBE and 3LPE coating on request. Specify coating type at time of enquiry.
Do you offer cut-to-length or value-added processing?
Yes. BB Infras offers cut-to-length, bevelling (30° per AWS/ASME), threading (NPT per ASME B1.20.1), grooving, galvanising, painting and stencilling in-house. Custom lengths from 0.5 m to 12 m available.
What are your payment terms and delivery methods?
We accept T/T, L/C at sight, and advance payment. Delivery is ex-works Mumbai or FOB JNPT/Nhava Sheva. For domestic customers we offer road transport; for export we arrange FCL/LCL container with full documentation.
Is API 5L Grade B suitable for high-temperature service?
API 5L Grade B is rated per API 5L Gr.B / ISO 3183. Heat treatment: Normalise or thermo-mechanical controlled rolling (TMCP).. Contact our technical team for temperature-derated stress values per ASME B31.3 Appendix A.

Get the best price for API 5L Grade B Threaded Flange

Talk to our sales team — available Mon–Sat, 9 AM – 7 PM IST. Same-day quotes.

Contact Us Today +91-9152677155
Reviewed by Abhishek Virkar
Industrial Piping Specialist • 12+ Years Experience • BB Infras, Mumbai
This page has been reviewed for technical accuracy against API 5L Gr.B / ISO 3183 standard requirements. Last updated: June 2026.

People Also Ask

What pressure classes are available for API 5L Grade B Threaded Flange?

API 5L Grade B Threaded Flange is available in 150#, 300#, 600#, 900#, 1500# and 2500# per ASME B16.5. For NPS > 24", ASME B16.47 Series A/B applies.

What facing options are available?

Available facings: Raised Face (RF), Flat Face (FF) and Ring Type Joint (RTJ). RF is the most common for general service.

What is the tensile and yield strength of API 5L Grade B?

Per API 5L Gr.B: minimum tensile is 415 MPa min and minimum yield is 245 MPa min. Forging heat treatment normalises the material to achieve these values.

Do API 5L Grade B flanges need PWHT after welding?

PWHT requirements depend on wall thickness and service per ASME B31.3 Section 331. For carbon steel flanges, PWHT typically applies for wall thickness above 19 mm or as specified by the engineer.

What is the price of API 5L Grade B Threaded Flange in India?

Prices vary by size, pressure class, quantity and market rates. Contact BB Infras for a firm quotation from our Mumbai stockyard.

Authoritative Standards Referenced

StandardIssuing BodyScope
API 5L Gr.B / ISO 3183ASTM / ASMEMaterial specification for API 5L Grade B
ASME B16.5ASMEPipe flanges and flanged fittings — NPS ½" – 24"
ASME B16.47ASMELarge diameter steel flanges — NPS 26" – 60"
EN 10204:2004CENMetallic products — types of inspection documents (3.1 MTC)
NACE MR0175 / ISO 15156NACE/ISOMaterials for H₂S service in oil and gas production
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