Positive line closure
Product formFlanges
/ 01 — TECHNICAL OVERVIEW
Blind Flanges
Blind Flanges are solid flanges used to close piping systems, valves, vessel nozzles and equipment connections. Selection should coordinate the material grade, dimensional standard, nominal size, pressure class, facing, drilling and inspection requirements.
NESCO Pipe & Tubes supplies stainless steel, duplex, super duplex, nickel-alloy, titanium and copper-nickel Blind Flanges for isolation, inspection access and future line extension.
The flange must be selected for the complete design pressure, temperature and bolting load under the approved piping specification.
How it is made
01
Forged, cast or permitted plate material is selected to the specified class and material standard.
02
The solid blank is heat treated where required and rough machined to the flange profile.
03
Facing, thickness, outside diameter and bolt-hole geometry are finish machined without a centre bore.
04
Gasket seating finish and pressure-class dimensions are inspected carefully.
05
Material traceability, NDT where ordered, marking and face protection complete the supply.
Request reviewed quotation Material documents on request
/ 02 — PRODUCT DETAIL
Built around the specification.
Blind flanges close the end of a piping system, nozzle or valve connection. They permit future access for inspection or extension and must be selected for the full design pressure, temperature and bolting load.
Key features01 02 03 04
No centre bore
Useful for inspection openings and future expansion
Thickness and facing depend on size, class and standard
Common specification references
STD
ASME B16.5 / B16.47 as applicable
STD
Material specification matched to piping class
STD
Facing and bolt-hole requirements per project
Explore the flanges range
/ 03 — AVAILABLE GRADES
Available Material Grades
NESCO supplies the material families shown below in flange form, subject to flange type, grade, size, pressure class, facing, bore and availability.
Material familyCommon gradesTypical selection context
Stainless Steel304, 304L, 316, 316L, 310S, 317L, 321, 347, 347H and 904L
General process piping, chemical service, pressure and elevated-temperature applications
Duplex Stainless SteelUNS S31803, UNS S32205 (2205), UNS S32750 (2507) and UNS S32760
High-strength applications and chloride-bearing environments
Nickel AlloysAlloy 20, Alloy 28, Alloy 200, Alloy 201, Monel 400, Inconel 600, Inconel 601, Inconel 625, Inconel 718, Incoloy 800, Incoloy 800H, Incoloy 800HT, Incoloy 825, Hastelloy C276 and Hastelloy C22
Severe corrosion, high-temperature and demanding chemical/process service
TitaniumGrade 2, Grade 5 and other applicable grades
Seawater, chemical processing and lightweight corrosion-resistant applications
Cupro NickelCu-Ni 90/10 (C70600) and Cu-Ni 70/30 (C71500)
Marine, seawater, condenser and heat-exchanger systems
/ 04 — SUPPLY & CUSTOMISATION
Define the supply condition.
Final availability depends on the complete combination of material, dimensions, standard, condition, testing and quantity.
ParameterTypical information to specify
01Standard
ASME B16.5, ASME B16.47 or applicable project / drawing requirements
02Size & bore
NPS / DN, bore and pipe schedule where applicable
03Pressure class
Class 150, 300, 400, 600, 900, 1500 and 2500, as applicable to the selected standard and size
04Facing
Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ) or other specified facing
05Dimensions
Outside diameter, flange thickness, bolt circle, bolt-hole diameter / quantity and hub dimensions, as applicable
06Machining & finish
Bore machining, hub profile, gasket seating surface and specified facing finish
07Marking & inspection
Grade, heat number, size, class, facing, standard, manufacturer identification and specified inspection requirements
/ 05 — DIMENSIONS & SIZE RANGE
Dimensions aligned to the manufacturing route.
Flange size alone is insufficient. The dimensional standard, pressure class, facing, bore and pipe outside diameter should be specified together.
Design inputTypical optionsRequired RFQ detailWhy it matters
Nominal sizeNPS / DNNominal pipe size and applicable standardEstablishes the flange size and dimensional basis
StandardASME B16.5, ASME B16.47, EN 1092-1 or project standardApplicable flange standardDetermines dimensions, drilling, tolerances and rating basis
Pressure ratingClass 150, 300, 400, 600, 900, 1500, 2500 or applicable PN ratingClass / PN rating and applicable standardEstablishes the pressure-temperature rating basis
FacingRF, FF, RTJ or other specified facingFacing type and required facing finishMust be compatible with the mating flange and gasket arrangement
Bore / pipe scheduleStandard bore, bore matched to pipe schedule or specified borePipe OD, wall thickness / schedule and required boreControls weld transition, alignment and internal flow passage
Dimensions / drillingStandard dimensional pattern or project-specificOD, thickness, bolt circle/PCD, bolt-hole size and number where requiredEnsures mating compatibility and correct installation
Material / gradeStainless, duplex, super duplex, nickel alloy, titanium or Cu-NiGrade and applicable material specificationDetermines mechanical, corrosion and temperature suitability
/ 06 — MANUFACTURING STANDARDS
Standards aligned for every order.
The material standard, dimensional standard and project requirements should be stated separately.
ReferenceWhat it coversRole
ASME B16.5Pipe flanges and flanged fittings, NPS 1/2 through NPS 24
Dimensions, pressure-temperature ratings, tolerances, marking and testing
ASME B16.47Large-diameter steel flanges, NPS 26 through NPS 60
Large-diameter flange dimensions, ratings and drilling
ASTM A182/A182MForged or rolled alloy and stainless-steel pipe flanges, fittings, valves and related pressure-system components
Material specification
ASTM B564Nickel-alloy forgings, including applicable nickel, Ni-Cu and nickel-alloy grades
Nickel-alloy material specification
ASTM B381Titanium and titanium-alloy forgings
Titanium material specification
EN 1092-1Circular steel flanges with PN designation
European dimensional and pressure-rating basis
Project specification / drawingNon-standard dimensions, bore, facing, drilling, tolerances, inspection or other project requirements
Order-specific requirements
/ 07 — INSPECTION & TESTING
Evidence before dispatch.
01MTC and forging heat traceability
02NPS, class, OD, thickness and bolt-circle checks
03Bore and hub dimensions
04Facing type and surface-finish verification
05PMI and hardness when specified
06UT or liquid-penetrant examination where ordered
07Marking and face-protection verification
08Testing and inspection arranged to the purchase order, approved ITP or project requirements
PACKAGING & MARKING
Protected and traceable.
01Machined faces protected with covers or non-abrasive separators
02Small flanges boxed; larger flanges secured on pallets
03Threads, RTJ grooves and bores protected from impact
04Heat and piece traceability retained after machining
05Export packages labelled with type, grade, NPS, class and PO
/ 08 — APPLICATIONS & INDUSTRIES
Engineered for demanding service environments.
From process plants to marine systems, NESCO coordinates material, dimensions and documentation around the operating conditions of each application.
01
Process piping connections02
Pressure vessels and nozzles03
Valves, pumps and compressors
04
Refineries and petrochemical plants
05
Power and steam systems
06
Marine and water systems
07
Chemical processing equipment08
Maintenance and shutdown projectsIndustries servedOne supply partner across critical sectors.
/ 09 — WHY NESCO PIPE & TUBES
Built for buyers who cannot leave details to chance.
From specification review to export documentation, NESCO coordinates the technical and commercial details as one complete supply requirement.
01
Specification control
NESCO reviews the grade, product standard, dimensions, condition and acceptance criteria as one coordinated requirement.
02
Multi-material sourcing
Stainless steel, duplex, nickel alloy, copper-nickel and titanium requirements can be combined within one project enquiry.
03
Traceable documentation
Heat numbers, MTCs and agreed inspection records are aligned with the purchase order before dispatch.
04
Inspection coordination
PMI, dimensional checks, NDT and third-party witnessing can be arranged against an approved inspection plan.
05
Value-added processing
Cutting, machining, end preparation, polishing or protective finishing can be reviewed with the base material supply.
06
Export-ready packing
Identification, surface protection and packing are planned around product geometry and the final transport route.
07
Responsive RFQ review
Technical and commercial inputs are consolidated early so queries are resolved before quotation and production.
08
One accountable supply desk
NESCO provides a single contact for material, processing, documentation, packing and delivery coordination.
/ 10 — FREQUENTLY ASKED QUESTIONS
Clear answers before you specify.
Quick guidance on product selection, standards, dimensions, inspection and documentation. For project-specific requirements, NESCO will review the complete enquiry with your team.
01How is blind-flange thickness selected?
Thickness depends on nominal size, pressure class, material group, design temperature and the governing dimensional standard.
02Can a blind flange be supplied with tapped holes?
Custom drilling or tapping may be possible against an approved drawing and engineering review.
03Which flange details are essential for quotation?
State type, material grade, dimensional standard, NPS, pressure class, bore or schedule, facing, finish, quantity and inspection.
04What is the difference between Class and PN ratings?
Class and PN belong to different flange standard systems and are not direct dimensional substitutes. Use the complete selected standard and rating.
05Why must facing finish be specified?
Gasket performance depends on facing type, groove geometry and surface finish. The piping specification should define the required gasket seating surface.
06Can custom flanges be manufactured to drawings?
Yes, subject to approved material, design responsibility, machining drawing, tolerances, testing and quantity.
/ 11 — REQUEST FOR QUOTATION Nesco direct sales desk
Ready to source?Start with the details you already have.
Our team will review the grade, dimensions, testing and delivery requirements together.