180° LR return elbows (butt weld return bends) made to ASME B16.9 in stainless steel, duplex (S32205 / S31803), super duplex (S32750 / S32760) and nickel alloy grades — including Alloy 625 (UNS N06625) as photographed.
Seamless ½”–24″ (DN15–DN600) · Welded ½”–40″ (DN15–DN1000) · Sch 5S – XXS
What Is a 180° Long Radius Return Elbow?
A 180° long radius return elbow reverses the direction of a pipe run through a U-shaped return. The product range covers stainless steel elbows, duplex stainless steel elbows, super duplex stainless steel elbows and nickel alloy elbows, with size, wall thickness and material requirements specified for each order.
Also called a 180 degree elbow, LR return elbow or butt weld return bend, this fitting connects parallel pipe runs where the layout requires a full reversal of flow direction. Long radius returns are selected by the required end diameter, center-to-center distance, back-to-face dimension and connecting pipe wall thickness.
For an ASME B16.9 order, specify the applicable standard edition and material specification together. A dimensional standard defines fitting geometry and tolerances; it does not replace the material specification or establish suitability for a particular process.
Key Specifications
| Product type | 180° long radius butt weld return elbow |
|---|---|
| Size (seamless) | ½”–24″ (DN15–DN600) — catalog-listed range |
| Size (welded) | ½”–40″ (DN15–DN1000) — catalog-listed range |
| Wall thickness | Sch 5S through heavy-wall options, including XXS — specify the exact schedule and its dimensional standard |
| Material families | Stainless steel, duplex stainless steel, super duplex stainless steel, nickel alloys (254 SMO and AL-6XN high-alloy options available) |
| Dimensional reference | ASME B16.9, subject to the specified edition and product size |
| Welding ends | End preparation to the agreed standard and purchase specification — bevel 37.5° ±2.5°, root face 1.6 ±0.8 mm per ASME B16.9 / B16.25 |
| Inspection & documentation | Dimensional inspection, material traceability, test requirements and certificate type defined in the purchase order |
Note: These are catalog ranges, not a guarantee that every size, schedule, material and manufacturing route is available in every combination. Confirm the required configuration when requesting a quotation. Sizes beyond the cited return-dimension table require an agreed drawing and acceptance basis.
Material Grades: Stainless Steel, Duplex, Super Duplex and Nickel Alloy Elbows
Select the material grade separately from the fitting dimensions. The following material options are listed in the supplied product information; the complete fitting grade, manufacturing class, heat treatment and inspection requirements are confirmed for the order.
| Material family | Catalog-listed grades | Material specification |
|---|---|---|
| Stainless steel elbows | 304 / 304L / 304H, 316 / 316L / 316H / 316Ti, 317L, 310S, 321 / 321H, 904L | ASTM A403/A403M (austenitic fitting grades) |
| Duplex stainless steel elbows | UNS S31803, S32205 | ASTM A815/A815M |
| Super duplex stainless steel elbows | UNS S32750, S32760 | ASTM A815/A815M |
| Nickel alloy elbows | UNS N04400, N06600, N06601, N06022, N06625, N08020, N08800, N08810, N08811, N08825 | ASTM B366/B366M |
| Additional high-alloy stainless options | 254 SMO, AL-6XN (UNS N08367) | Confirm grade designation and applicable fitting specification |
Alloy 625 elbow: UNS N06625 is an Alloy 625 designation. The photographed return elbow carries N06625 identification, making it a useful example of the nickel alloy product family. The marking alone does not replace a material certificate. For material selection, provide the process medium, temperature, pressure and corrosion conditions — grade names alone do not establish interchangeability or service suitability.
ASME B16.9 Dimensions: NPS 3 Example (mm)
The supplied REV A drawing uses the SI values in ASME B16.9-2024, Table 6.1-3 for long radius returns. The following NPS 3 values are standard reference dimensions, rather than measurements of the photographed fitting.
| Dimension | Nominal value | Tolerance |
|---|---|---|
| Outside diameter at the end, D | 88.9 mm | ±1.6 mm |
| Center-to-center distance, O | 229 mm | ±6 mm |
| Back-to-face dimension, K | 159 mm | ±6 mm |
Reference: ASME B16.9-2024, Table 6.1-3 and Table 11.2-1 (printed pages 10 and 28–29). Use SI and U.S. Customary table values independently. The drawing’s proposed t = 7.62 mm remains subject to confirmation against the specified schedule standard.
Engineering Drawing — 180° LR Return Elbow (ASME B16.9)
The REV A drawing shows the 180° LR return elbow geometry: outside diameter D, center-to-center dimension O, back-to-face dimension K, wall thickness t and the 37.5° ±2.5° butt weld end bevel with root face per ASME B16.9-2024 Table 8.1-1 / B16.25. Marking example: ELBOW 180LR 3″ SCH160 · B366 UNS N06625 GR.2 · ASME B16.9, with heat number for MTC traceability.
The drawing is a review reference with unresolved material and wall-thickness items. Use the final agreed manufacturing drawing and material documentation for order acceptance. A PDF copy is available via the Drawing Download button above.
Dimensional Standards and Material Requirements
ASME B16.9 dimensions: use the specified edition to define the applicable fitting dimensions, end preparation and tolerances. State the size, wall thickness, material and manufacturing requirements in the order.
Material specifications: ASTM A403/A403M, ASTM A815/A815M and ASTM B366/B366M address different material families. Confirm the exact grade and scope before applying a specification.
Other standards: the catalog also lists GB/T 12459, SH 3408, SH 3409, EN 10253-4, MSS SP-43, DIN 2605 and JIS B2313 as references. If your project uses one of these standards, provide its edition and required fitting details for review. Listing several standards does not mean that one fitting automatically complies with all of them. Agree any additional testing, EN 10204 3.1 certification, surface treatment and packaging requirements at quotation — ASME B16.9 does not itself require individual production hydrostatic testing of wrought fittings.
Project Applications and Selection Information
Return elbows may be considered for process pipework, equipment piping and compact layouts with parallel pipe runs. Chemical processing, petrochemical, marine and water-treatment projects are examples of procurement contexts in which the material and inspection specification must be matched to the service conditions.
For a meaningful comparison between a 316L stainless steel elbow, duplex elbow, super duplex elbow and nickel alloy elbow, specify the same size, wall thickness, dimensional standard and inspection basis. The final material choice depends on the project’s corrosion assessment and piping design requirements.
Prepare Your 180° Return Elbow Enquiry
Use the following specification format to request a configuration-specific quotation. Include an approved drawing when dimensions or tolerances differ from the standard table.
- 180° LR return elbow / butt weld ends
- Size: [NPS / DN] · Schedule or wall thickness: [value + standard]
- Material: [grade + material specification + edition]
- Manufacturing route: [seamless / welded + required class]
- Dimensions: [standard + edition / approved drawing]
- Quantity: [pieces] · Inspection: [requirements] · Certificate: [type]
- Delivery: [destination + requested date]
Example enquiry: 180° LR butt weld return elbow, NPS 3, SCH160, UNS N06625, ASME B16.9 dimensions. Please confirm the ASTM B366/B366M edition, complete fitting grade/class, heat-treatment condition, wall thickness, inspection documents and delivery details.
FAQ: 180° Long Radius Return Elbows
What is a 180° long radius return elbow?
It is a U-shaped butt weld pipe fitting that reverses a pipe run by 180 degrees. It is also described as a 180 degree LR return elbow or return bend.
Which materials are listed for the return elbow range?
The catalog lists stainless steel, duplex stainless steel, super duplex stainless steel and nickel alloys. Examples include 304L, 316L, UNS S32205, S32750, S32760 and N06625. Confirm the exact grade and available size combination at quotation.
What is the difference between O and K?
O is the center-to-center distance between the two ends. K is the back-to-face dimension. For NPS 3 in ASME B16.9-2024 SI Table 6.1-3, O is 229 mm and K is 159 mm.
Does long radius mean 1.5 times the outside diameter?
Do not calculate this return elbow’s dimensions by multiplying the actual outside diameter by 1.5. Use the applicable standard table for O and K; Table 6.1-3 notes that dimension A equals O/2.
Is the fitting in the photograph stainless steel?
The visible marking identifies the photographed example as B366, UNS N06625, GR.2, NPS 3, SCH160. UNS N06625 is Alloy 625, a nickel alloy. Final material acceptance requires traceability to the material certificate.
What information is needed for a quotation?
Provide the angle and return type, size, schedule or wall thickness, material grade, manufacturing route, standard editions, quantity, inspection requirements, certificate type and delivery destination.
