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Description
A 180 degree return bend turns a line back on itself, so the outlet runs parallel to the inlet. One fitting does the work of two 90° elbows and the spool between them: one U, two welds, no intermediate joint.
We manufacture carbon steel return bends in ASTM A234 WPB, in long radius to ASME B16.9 and short radius to ASME B16.28. The two are not dimensionally interchangeable — the short radius return is a much tighter U. Return bends are also produced in ASTM A192 for heater coil and boiler service, and in any grade your specification calls for.
Return bends are the standard answer where a line has to reverse direction in a confined space: heater coils, exchanger bundles, steam tracing loops and compact pipe rack runs.
Butt weld fittings carry no pressure class. Wall thickness comes from the pipe schedule, so the schedule has to be stated at quotation stage. Every shipment leaves with an EN 10204 3.1 material certificate, traceable to the heat number.
180° Return Bends (Long Radius and Short Radius)
Specifications
| Item | Specification |
|---|---|
| Product | 180° return bend (U bend), long radius (LR) and short radius (SR) |
| Material | ASTM A234 WPB (carbon steel); ASTM A192 available for heater coil and boiler service |
| Standard | ASME B16.9 (long radius return); ASME B16.28 (short radius return) |
| Centerline radius | LR = 1.5 × NPS; SR = 1.0 × NPS |
| Center-to-center dimension | Taken from the ASME B16.9 / B16.28 tables — twice the center-to-end dimension of the matching 90° elbow (3 × NPS for long radius, 2 × NPS for short radius) |
| Size range | NPS 1/2″ to 24″ as standard in seamless construction; larger sizes in welded construction on request |
| Wall thickness | Specified by pipe schedule — SCH 10 / 20 / 40 / 80 / 120 / 160 / XS / XXS |
| Pressure rating | Butt weld fittings do not carry a pressure class. Capability is determined by the pipe schedule, the material and the applicable piping code, such as ASME B31.3 |
| End preparation | Bevelled to ASME B16.25 |
| Manufacturing | Seamless, hot formed, as standard up to NPS 24; welded construction for larger sizes |
| Heat treatment | Per ASTM A234 WPB — normalised, normalised and tempered, or stress relieved, as specified |
| Surface | Black as standard; shot blasted, oiled or painted on request |
| Certification | EN 10204 3.1 material test certificate, traceable to heat number |
| Lead time | Standard sizes in regular material take 7-15 days; non-standard sizes, non-standard schedules and special requirements take 20-35 days. Sea freight to the Gulf is additional and depends on the destination port. Lead time is confirmed in writing with your quotation and is subject to the production schedule at the time of order. |
| HS code | 7307.93 |
Applications
- Heater and furnace coils, where the tube has to run back and forth
- Heat exchanger and condenser tube bundles
- Steam tracing return loops and condensate return runs
- Compact U-turns in pipe racks, where there is no room for two elbows and a spool
- Tank farm and terminal piping, where a line reverses at a header
- Vent, drain and by-pass loops on process skids
- EPC contractors and overseas infrastructure projects — water transmission mains, district cooling networks, airport and industrial park piping, supplied to the project specification and the document package your QA team requires
Samples, Third-Party Inspection and Test Records
Sample pieces can be produced before the batch runs, so that dimensions, bevel profile and fit-up can be checked on your side first. Sample cost and delivery time are advised with the quotation, based on size and material.
Buyer-nominated inspection is supported. SGS, BV, Intertek or your own inspector can witness dimensional checking, marking, coating and container loading at the production site, and we provide the documents and site access needed for the visit. Where a visit is not practical, the same checks can be followed through a live video walkthrough. Third-party inspection fees are normally carried by the buyer.
Non-destructive testing and hydrostatic test records are available on request and can be shipped with the order, together with the EN 10204 3.1 material certificate, the heat number and marking list, dimensional records, packing list and certificate of origin. Tell us at enquiry stage which records your project requires, and they are included in the quotation.
Long Radius or Short Radius
Long radius (LR) Short radius (SR)
Standard ASME B16.9 ASME B16.28
Centerline radius 1.5 × NPS 1.0 × NPS
Center-to-center 3 × NPS 2 × NPS
Space required More Less
Pressure drop Lower Higher
Typical use Process lines and heater coils where flow matters Tight layouts, tracing loops, low velocity utility lines
The short radius return is the tightest U available as a standard fitting. It saves space, but it adds pressure drop and puts more wear on the outer radius. On heater coils and any service with thermal cycling, long radius is the safer choice.
For a right-angle turn, see 90 degree elbows. For a partial change of direction, see 45 degree elbows.
FAQ
Q1: Is a 180 degree return bend covered by ASME B16.9 or B16.28?
Both, depending on the radius. ASME B16.9 covers the long radius return (1.5 × NPS); ASME B16.28 covers the short radius return (1.0 × NPS). They are different fittings with different dimensions, not two versions of the same one.
Q2: What is the difference between a long radius return and a short radius return?
The tightness of the U. Center-to-center is 3 × NPS for long radius and 2 × NPS for short radius — the short radius return takes noticeably less space. That space is paid for with higher pressure drop and more erosion at the outer radius.
Q3: Are return bends seamless or welded?
Seamless, hot formed, as standard up to NPS 24. Larger sizes are supplied in welded construction. For heater and coil service, seamless is the normal specification.
Q4: Where are 180 degree return bends used?
Wherever a line has to reverse direction: heater and furnace coils, heat exchanger bundles, steam tracing return loops, compact pipe rack U-turns, and vent or drain loops on skids.
Q5: Can one return bend replace two 90 degree elbows and a spool?
Yes. It is one fitting instead of three pieces, and two girth welds instead of four — fewer joints to weld, inspect and potentially leak. The trade-off is that the U is a fixed dimension: there is no spool to trim if the fit-up is out.
Q6: How much straight pipe is needed between the two welds of a return?
Enough to keep the heat-affected zones apart and to let each weld be examined properly. On small sizes in particular, check the tangent length against your welding procedure and NDT access before finalising the layout.
Q7: What schedule should I specify for a return bend in a heater coil?
Match the tube or pipe you are welding to, and state it at quotation stage. Coil service adds thermal cycling and, at temperature, creep — so the material grade and heat treatment have to suit the tube, not just the line class.
Q8: Can you supply return bends with extended tangents or to a drawing?
Yes. Extended tangents, non-standard radii and complete coil assemblies are made to drawing. This is common for heater coil fabrication, where the bend geometry has to match the tube layout exactly.
Q9: Can return bends be supplied in low-temperature or alloy grades?
Carbon steel to ASTM A234 WPB is standard. Low-temperature grades such as ASTM A420 WPL6 and high-temperature alloy grades such as ASTM A234 WP11 and WP22 are supplied on request, with heat treatment to the grade. ASTM A192 return bends for heater coil and boiler service are produced to order, and the grade is stamped on the fitting and matched to the EN 10204 3.1 certificate.
Q10: Can we arrange third-party inspection before shipment?
Yes. SGS, BV or your nominated inspector is welcome before dispatch. Dimensional and visual examination is standard on every order; UT, RT or any additional NDT is specified and quoted at enquiry stage.
Q11: What sizes and pressure ratings are available for 180 degree return bends?
NPS 1/2 inch to 24 inch as standard in seamless construction, with larger sizes in welded construction on request. Wall thickness is specified by pipe schedule. Sizes and ratings outside this range can be reviewed against your drawing. The exact range confirmed for your order is stated in the quotation.
Q12: How is the wall thickness determined for 180 degree return bends?
Butt-weld fittings do not carry a pressure class. Wall thickness is specified by the pipe schedule (SCH 10 / 20 / 40 / 80 / 120 / 160 / XS / XXS), and the schedule must be stated when you request a quotation.
Q13: What is the lead time for 180 degree return bends?
Standard sizes in regular material normally take 7-15 days. Non-standard sizes, special materials and custom orders take longer. The exact lead time for this product is given in the specification table on this page and is confirmed in writing with your quotation. Sea freight to the Gulf is additional and depends on the destination port. All lead times are subject to the production schedule at the time of order.
Q14: Is there a minimum order quantity for 180 degree return bends?
There is no fixed minimum. Standard items can ship from a single pallet, and custom production is normally quoted at full container load. Small trial orders and mixed-size orders are accepted. Send your size list and we will confirm what can be combined in one shipment.
Q15: How are 180 degree return bends packed and marked?
Flanges and fittings are packed in plywood cases or on plywood pallets with anti-rust treatment, strapped and stretch-wrapped for sea freight. Each piece carries the heat number, and the material, size, standard and pressure class or schedule are marked on the item or on the case label. Shipping marks are printed to your specification, and a fumigation certificate is provided where wooden packaging is used.
Q16: Can you produce 180 degree return bends to our drawing or to non-standard specifications?
Yes. Send the drawing, material, quantity and the applicable standard, and we will confirm feasibility and quote. Non-standard angles, non-standard schedules, special materials and special dimensions are produced against your drawing. The details we need to quote are listed on our custom service page. The details we need to quote are listed on our custom service page.
Engineer’s Note
Four things decide whether a return bend performs on site.
Two welds, close together. A return puts two girth welds a short distance apart. Leave enough straight tangent between them so the heat-affected zones do not overlap, and so each weld can be examined properly.
Fixed geometry. A return bend is a fixed U: no spool to trim, no adjustment on site. Where the fit-up has to be adjustable, two 90° elbows and a spool give you room to work with.
Coil and heater service. Coils see thermal cycling and, at temperature, creep. Specify material grade and heat treatment to match the tube, and confirm the schedule against the tube wall rather than the line class alone.
Radius is not cosmetic. Short radius returns exist because space is tight, not because they flow better. On any line carrying velocity or solids, the tighter U wears at the outer radius first.
Enquiry
Send the size, the schedule, the radius (LR or SR), the quantity and the service. For coil assemblies, send the drawing. We usually quote within 24 hours.
Frequently Asked Questions
Is a 180 degree return bend covered by ASME B16.9 or B16.28?
Both, depending on the radius. ASME B16.9 covers the long radius return (1.5 x NPS); ASME B16.28 covers the short radius return (1.0 x NPS). They are different fittings with different dimensions, not two versions of the same one.
What is the difference between a long radius return and a short radius return?
The tightness of the U. Center-to-center is 3 x NPS for long radius and 2 x NPS for short radius, so the short radius return takes noticeably less space. That space is paid for with higher pressure drop and more erosion at the outer radius.
Are return bends seamless or welded?
Seamless, hot formed, as standard up to NPS 24. Larger sizes are supplied in welded construction. For heater and coil service, seamless is the normal specification.
Where are 180 degree return bends used?
Wherever a line has to reverse direction: heater and furnace coils, heat exchanger bundles, steam tracing return loops, compact pipe rack U-turns, and vent or drain loops on skids.
Can one return bend replace two 90 degree elbows and a spool?
Yes. It is one fitting instead of three pieces, and two girth welds instead of four: fewer joints to weld, inspect and potentially leak. The trade-off is that the U is a fixed dimension, with no spool to trim if the fit-up is out.
How much straight pipe is needed between the two welds of a return?
Enough to keep the heat-affected zones apart and to let each weld be examined properly. On small sizes in particular, check the tangent length against your welding procedure and NDT access before finalising the layout.
What schedule should I specify for a return bend in a heater coil?
Match the tube or pipe you are welding to, and state it at quotation stage. Coil service adds thermal cycling and, at temperature, creep, so the material grade and heat treatment have to suit the tube, not just the line class.
Can you supply return bends with extended tangents or to a drawing?
Yes. Extended tangents, non-standard radii and complete coil assemblies are made to drawing. This is common for heater coil fabrication, where the bend geometry has to match the tube layout exactly.
Can return bends be supplied in low-temperature or alloy grades?
Carbon steel to ASTM A234 WPB is standard. Low-temperature grades such as ASTM A420 WPL6 and high-temperature alloy grades such as ASTM A234 WP11 and WP22 are supplied on request, with heat treatment to the grade. ASTM A192 return bends for heater coil and boiler service are produced to order, and the grade is stamped on the fitting and matched to the EN 10204 3.1 certificate.
Can we arrange third-party inspection before shipment?
Yes. SGS, BV or your nominated inspector is welcome before dispatch. Dimensional and visual examination is standard on every order; UT, RT or any additional NDT is specified and quoted at enquiry stage.
What sizes and pressure ratings are available for 180 degree return bends?
NPS 1/2 inch to 24 inch as standard in seamless construction, with larger sizes in welded construction on request. Wall thickness is specified by pipe schedule. Sizes and ratings outside this range can be reviewed against your drawing. The exact range confirmed for your order is stated in the quotation.
How is the wall thickness determined for 180 degree return bends?
Butt-weld fittings do not carry a pressure class. Wall thickness is specified by the pipe schedule (SCH 10 / 20 / 40 / 80 / 120 / 160 / XS / XXS), and the schedule must be stated when you request a quotation.
What is the lead time for 180 degree return bends?
Standard sizes in regular material normally take 7-15 days. Non-standard sizes, special materials and custom orders take longer. The exact lead time for this product is given in the specification table on this page and is confirmed in writing with your quotation. Sea freight to the Gulf is additional and depends on the destination port. All lead times are subject to the production schedule at the time of order.
Is there a minimum order quantity for 180 degree return bends?
There is no fixed minimum. Standard items can ship from a single pallet, and custom production is normally quoted at full container load. Small trial orders and mixed-size orders are accepted. Send your size list and we will confirm what can be combined in one shipment.
How are 180 degree return bends packed and marked?
Flanges and fittings are packed in plywood cases or on plywood pallets with anti-rust treatment, strapped and stretch-wrapped for sea freight. Each piece carries the heat number, and the material, size, standard and pressure class or schedule are marked on the item or on the case label. Shipping marks are printed to your specification, and a fumigation certificate is provided where wooden packaging is used.
Can you produce 180 degree return bends to our drawing or to non-standard specifications?
Yes. Send the drawing, material, quantity and the applicable standard, and we will confirm feasibility and quote. Non-standard angles, non-standard schedules, special materials and special dimensions are produced against your drawing. The details we need to quote are listed on our custom service page.
Related products
- 90° butt weld elbows
- 45° butt weld elbows
- carbon steel butt weld tees
- EN 10204 3.1 material certificate