Buttweld Pipe End Cap Manufacturer, Supplier & Exporter
A buttweld pipe end cap is a dished fitting welded onto the end of a pipe to close it permanently. Raaj Fittings manufactures and exports end caps to ASME B16.9 in stainless steel, duplex and super duplex, nickel alloys, carbon steel and alloy steel, from light-wall SCH 5S up to XXS.
The curved, roughly elliptical shape of the cap spreads internal pressure evenly, much like the head of a pressure vessel, so the cap is as strong as the pipe it closes. Because it is butt-welded, the closure is permanent and leak-tight, with no gasket or bolting to maintain.
Every cap is bevelled to the pipe schedule and supplied with EN 10204 3.1 mill test certificates, with 3.2 certification on request.
We export pipe end caps to EPC contractors, refineries and stockists across the Middle East and GCC, Europe and the Americas — to ASME B16.9 for US and Gulf projects, or EN 10253 / DIN dimensions for European specifications, with PED-compliant supply on request.
Pipe End Cap Specifications
½" NPS to 48" NPS and larger to order
SCH 5S, 10S, 40S, 80S, 10 to 160, STD, XS, XXS
Dished, approximately elliptical head with a straight flange (skirt) to the weld end
Seamless (pressed or forged) and welded from plate for large sizes
Bevelled end for butt welding to ASME B16.25
EN 10204 3.1 mill test certificate as standard; EN 10204 3.2 on request
Materials & Grades
We supply pipe end caps in the following materials and grades. All grades are supplied with EN 10204 3.1 / 3.2 Mill Test Certificates.
Stainless Steel Pipe End Caps
Stainless steel buttweld fittings deliver excellent corrosion resistance and are essential in chemical, pharmaceutical, food processing, and marine environments. All grades supplied to ASTM A403 specification.
(ASTM A403 WP304 / WP304L) General corrosion resistance; food, dairy, and chemical service
(ASTM A403 WP316 / WP316L) Enhanced chloride and acid resistance; pharmaceutical, marine, and chemical processing
(ASTM A403 WP316H) Elevated-temperature creep strength for high-temperature process service
(ASTM A403 WP317 / WP317L) Higher molybdenum content; superior corrosion resistance in concentrated acid service
(ASTM A403 WP321) Titanium-stabilised; resists sensitisation at sustained elevated temperatures
(ASTM A403 WP347) Columbium-stabilised; ideal for heat exchangers and high-temperature piping
High-alloy austenitic; superior resistance to hot concentrated sulfuric and phosphoric acids
Duplex & Super Duplex Stainless Steel Pipe End Caps
Duplex and super duplex grades offer approximately twice the yield strength of standard austenitic stainless steel, combined with excellent resistance to stress corrosion cracking and pitting — ideal for offshore, subsea, and chemical processing environments.
(UNS S31803 / S32205) Offshore topsides, chemical plant, desalination, and seawater piping
(UNS S32750) Seawater systems, subsea equipment, FPSOs, and high-chloride offshore environments
(UNS S32760) High-temperature, high-chloride offshore and subsea service applications
Nickel Alloy Pipe End Caps
For the most aggressive corrosive environments — concentrated acids, caustic solutions, sour gas service, and extreme temperatures — we offer buttweld fittings in a full range of nickel alloys.
(UNS N06600) High-temperature oxidation and carburisation resistance
(UNS N06625) Outstanding broad-spectrum corrosion resistance; offshore, chemical, and subsea service
(UNS N08825) Resistance to phosphoric and sulfuric acids; FGD systems and chemical plant
(UNS N10276) Universal corrosion resistance across the widest range of aggressive process media
(UNS N06022) Superior resistance to oxidising and reducing acids and pitting attack
(UNS N04400) Suitable for seawater, hydrofluoric acid, and marine and alkali service
(UNS N08020) Engineered for sulfuric acid and aggressive chemical process service
Exceptional corrosion resistance in seawater and oxidising media at low density
(C70600 / C71500) Preferred for marine seawater piping and naval condenser systems
Carbon Steel Pipe End Caps
Carbon steel is the most widely specified material for general-purpose, hydrocarbon, and elevated-temperature service. The primary grade is ASTM A234 WPB for standard service. For high-yield pipeline fittings, we supply ASTM A860 WPHY grades to MSS SP-75.
Standard carbon steel; primary grade for general-purpose process piping buttweld fittings
Impact-tested carbon steel for low-temperature service down to -46°C (-50°F); LNG and cryogenic piping
High-yield pipeline fittings to MSS SP-75; used in high-pressure oil, gas, and liquid transmission pipelines
Alloy Steel Pipe End Caps
Chromium-molybdenum alloy steel buttweld fittings are specified for high-temperature, high-pressure service in power generation, petrochemical, and refinery applications. All grades supplied to ASTM A234 specification.
(5% Cr · ½% Mo) Refinery high-temperature service; hydrotreating and catalytic reforming units
(9% Cr · 1% Mo) High-temperature hydrogen-rich process service and steam piping
(1¼% Cr · ½% Mo) Thermal power plant steam, feedwater, and reheat piping
(2¼% Cr · 1% Mo) Reactors and high-temperature pressure piping systems in petrochemical plants
(9% Cr · 1% Mo · V · Nb) Ultra-supercritical steam power plant main steam and hot reheat piping
Where Pipe Caps Are Used
An end cap closes a line that will not need to be opened again. It is lighter and cheaper than a blind flange with its mating flange, gaskets and bolts, and has no joint to leak. ASME B16.9 gives the cap length for each size — for example 64 mm for a 4" cap in standard wall — with a longer length for heavier walls.
- Dead ends of headers — closes the far end of distribution headers and manifolds.
- Drip legs and dirt pockets — forms the bottom of collection legs on steam and gas lines.
- Pig trap and vessel ends — used where a fixed closure is acceptable.
- Pressure testing — temporary welded closure for testing spools before installation.
Cap or Blind Flange?
Use a cap when the closure is permanent and no access is needed. Use a blind flange on a weld neck flange where the line may need to be opened later for extension, cleaning or inspection.
Specifying a Cap
Give the size, the schedule of the pipe it will be welded to, the material grade and construction — for example 6" SCH 80 pipe cap, ASTM A234 WPB, seamless. Caps can also be supplied with a centre outlet for a vent, drain or instrument, made to order.
Applications & Industries
- Header and manifold ends in refineries, petrochemical and gas plants
- Steam drip legs and condensate pockets in power plants
- Pipeline and spool pressure-test closures
- Offshore and seawater systems in duplex and super duplex
- Fire water, utility and drain systems
- Chemical and pharmaceutical lines in stainless steel and nickel alloys
Explore the full range of buttweld fittings; for small-bore lines see the forged cap.
Testing, Inspection, Marking & Packing
End caps are made under our quality assurance process:
- Incoming material verification with PMI testing
- Chemical and mechanical testing to the applicable ASTM specification
- Heat treatment after forming as required, with pickling and passivation for stainless steels
- Dimensional inspection of length, outside diameter, wall thickness at the knuckle and bevel
- Marking with grade, size, schedule and heat number
Supplied with EN 10204 3.1 mill test certificates; EN 10204 3.2 certificates and third-party inspection are available on request.
Fittings are packed for export with plastic end caps protecting the bevels, rust-preventive or VCI wrapping on carbon and alloy steel, and seaworthy wooden cases; marking, tagging and packing to your specification are available on request.
Why Choose Raaj Fittings for Pipe End Caps?
Raaj Sagar Steels has supplied piping components since 2003 and today manufactures buttweld fittings at two plants in India for buyers in the Middle East, Europe and the Americas.
- Manufactured in-house — Pipe end caps are made in our own plants, so material, dimensions and delivery stay under our control.
- Ready stock, short lead times — common sizes and grades are held in stock for prompt dispatch; other sizes, grades and specials are manufactured to order.
- Certified quality — ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certified; PED 2014/68/EU and IBR supply available, and NACE MR0175 / ISO 15156 material on request.
- 100% material verification — PMI testing on incoming material and EN 10204 3.1 mill test certificates with every order; 3.2 certificates on request.
- Third-party inspection ready — we regularly work with SGS, Bureau Veritas, TÜV and DNV.
- Export documentation — MTCs, certificates of origin, packing lists and inspection reports to suit projects in the GCC, Europe and the Americas.
- Export packing — seaworthy packing with end and face protection, and packing to your specification on request.
- Fast response — our team replies to enquiries within one business day.
Pipe End Caps — FAQs
A buttweld pipe cap is a dished fitting welded to the end of a pipe to close it permanently. Its curved shape carries internal pressure like a vessel head.
A pipe cap is welded on and cannot be removed without cutting. A blind flange is bolted to a flange and can be opened again, but needs a mating flange, gaskets and bolts.
ASME B16.9 gives the length for each size — for example 64 mm for a 4" cap in standard wall. Heavier walls have a longer length.
Yes. Caps can be supplied with a centre outlet for a vent, drain or instrument connection, made to order.
Carbon steel (ASTM A234 WPB, A420 WPL6, A860 WPHY), alloy steel (WP5 to WP91), stainless steel (A403), duplex, super duplex and nickel alloys.
Yes. We supply pipe end caps for projects under the European Pressure Equipment Directive (PED 2014/68/EU), and with IBR certification for Indian boiler applications. NACE MR0175 / ISO 15156 compliant material is also available on request for sour service in the Middle East and the Americas.
