180° Long Radius Return Bend Manufacturer, Supplier & Exporter
A 180° long radius return bend reverses the direction of flow so that a pipe turns back parallel to itself. Its centreline radius is 1.5 times the nominal pipe size (R = 1.5D). Raaj Fittings manufactures and exports long radius return bends to ASME B16.9 in stainless steel, alloy steel, carbon steel, duplex and nickel alloys, in seamless and welded construction.
Return bends are the building block of serpentine coils and multi-pass piping: heater and furnace coils, heat exchanger and cooler bundles, and tracing loops. The long radius keeps pressure drop and erosion low, and the one-piece fitting replaces two 90° elbows and the weld between them.
Every return bend is supplied with EN 10204 3.1 mill test certificates, with 3.2 certification on request.
We export 180° long radius return bends 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.
180° LR Return Bend Specifications
½" NPS to 24" NPS; larger sizes to order
Long radius: centreline radius 1.5 × NPS; centre-to-centre 3 × NPS
SCH 5S to XXS, including STD, XS, SCH 40, 80 and 160
Seamless (SMLS) and welded (ERW / EFW)
Bevelled ends 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 180° long radius return bends in the following materials and grades. All grades are supplied with EN 10204 3.1 / 3.2 Mill Test Certificates.
Stainless Steel 180° Long Radius Return Bends
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 180° Long Radius Return Bends
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 180° Long Radius Return Bends
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 180° Long Radius Return Bends
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 180° Long Radius Return Bends
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 Return Bends Are Used
When a pipe must double back on itself — to make a coil, a loop or a multi-pass bundle — a return bend does it in a single fitting. The two ends of a long radius return bend are three nominal diameters apart centre to centre, so a 4" return bend spaces the parallel legs about 305 mm apart.
- Furnace and heater coils — connect tube passes in fired heaters, often in alloy steel such as ASTM A234 WP5, WP9 or WP91.
- Heat exchangers and coolers — link tube passes in hairpin and air-cooled exchangers.
- Expansion loops — form the turnarounds in pipe loops that absorb thermal expansion.
- Steam tracing and jacket coils — make tight, compact serpentine runs.
Long Radius or Short Radius Return?
A long radius return gives lower pressure drop and erosion and is the normal choice. A 180° short radius return bend (R = 1D) brings the legs closer together — two diameters apart — for very compact coils. Where a turn must be built from separate fittings, two 90° long radius elbows can be welded together, at the cost of an extra weld.
Dimensions to Check
Besides the centre-to-centre dimension, ASME B16.9 gives a back-to-face dimension — from the outside of the bend to the plane of the ends — which sets how far the coil projects. Both dimensions should be confirmed against your layout.
Applications & Industries
- Fired heater and furnace coils in refineries and petrochemical plants
- Heat exchanger, hairpin and air-cooler bundles
- Boiler and economiser coils in power plants
- Thermal expansion loops in pipe racks
- Chemical and pharmaceutical process coils in stainless steel and nickel alloys
Explore the full range of buttweld fittings.
Testing, Inspection, Marking & Packing
Return bends are made under our quality assurance process:
- Incoming material verification with PMI testing
- Chemical and mechanical testing to the applicable ASTM specification
- Heat treatment as required, including normalising and tempering of chrome-moly grades
- Radiographic or ultrasonic examination of the weld seam on welded bends
- Dimensional inspection of centre-to-centre, back-to-face, wall thickness 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 180° Long Radius Return Bends?
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 — 180° long radius return bends 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.
180° Long Radius Return Bends — FAQs
A 180° return bend reverses the direction of a pipe so it runs back parallel to itself. It is used to connect passes in coils, heat exchangers and loops.
It is three times the nominal pipe size — for example about 152 mm for a 2" bend and 305 mm for a 4" bend. ASME B16.9 tabulates exact values.
A long radius return has R = 1.5D and legs 3D apart, with lower pressure drop. A short radius return has R = 1D and legs 2D apart, for more compact coils.
Furnace and heater coils often use chrome-moly alloy steels such as ASTM A234 WP5, WP9, WP11, WP22 and WP91, or stainless steels such as 321 and 347 for high temperatures.
Yes. A long radius return bend has the same geometry as two long radius 90° elbows welded together, but saves one weld and its inspection.
Yes. We supply 180° long radius return bends 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.
