Ductile Iron 90° Long Radius Elbow — Low-Loss Direction Change

By Nico Yin · Qingdao Zhaoyuqi Machinery Co., Ltd.

Overview

A 90° long radius (LR) elbow turns a pipeline through a right angle using a bend radius typically 1.5 times the nominal pipe size — larger than the tight radius of a standard street or reducing elbow. That extra radius is not cosmetic: it lowers turbulence, reduces pressure loss across the fitting, and slows erosion of the casting wall where abrasive or high-velocity media strike the outer curve. Our long radius elbows are sand-cast in ductile iron to ASTM A536-84(2019), then fully machined at the ends for threading or flanging.

They are specified where flow efficiency and service life matter more than compactness: water transmission mains, sewage and slurry lines, dredging circuits, and pump suction/discharge runs where every fraction of head loss counts. Compared with a short radius elbow of the same size, an LR elbow typically shows measurably lower resistance coefficient (K value) in standard flow references, and its thicker heel wall withstands particle impingement better over years of service. Sizes cover 1/2" through 12", threaded or flanged to suit the line.

Specifications

Customization & Sampling

Long radius elbows are frequently custom-cast: we can adjust bend radius (e.g., 2× NPS for slurry duty), add flanges of a specific drilling, extend one leg for weld-over or grooving, or core a larger waterway for low-velocity applications. The sampling sequence is drawing/DFM review → pattern work → first article → dimensional and wall-thickness report → approval → production. Samples are typically delivered in 3–5 weeks. Reverse engineering from a worn sample is available for legacy water-works spares.

Quality Inspection & Packaging

Chemistry per heat is checked on an optical emission spectrometer against A536 limits, and mechanical test bars from the same melt confirm tensile, yield, and elongation. Dimensional QC focuses on the parameters that matter for an LR elbow: center-to-face dimension, squareness of the two ends, heel and throat wall thickness, and flange face finish. Hydrostatic proof testing is offered for project orders. After painting or galvanizing, parts are packed with flange protectors in plywood cases or on pallets. Manufacturing follows a quality management system conforming to ISO 9001:2015 requirements.

FAQ

Q1: When should I choose a long radius elbow instead of a standard one?

Choose LR when the medium is abrasive or high-velocity, when system head loss is tight, or when the pump manufacturer asks for reduced turbulence at suction/discharge. Standard short-radius elbows are fine for compact, low-flow threaded lines.

Q2: Can you cast a bend radius other than 1.5×NPS?

Yes. Radius, leg lengths, and wall build-up at the heel are all pattern-controlled, so 2×NPS or other project radii are routine work. Send the centerline drawing and we will quote tooling and piece price.

Q3: What coating do you recommend for a sewage line?

A fusion-bonded or two-part liquid epoxy inside and out gives the best protection against corrosive sewer gas and wet soil; hot-dip galvanizing suits outdoor atmospheric exposure. Both are applied after dimensional inspection.

Related Products

• Elbow (Standard 90°)

• 90° Base Elbow

• 90° Reducing Elbow

• Ductile Iron Flanged Eccentric Reducer

• Concentric Reducer

Get a Quote

For long radius elbows, WhatsApp usWhatsApp us at +86 185 6156 7088 the size, end type (threaded or flanged), bend radius, and coating, plus target quantity and port of destination. Our export desk returns a quotation with casting lead time — typically within one working day — and can arrange first-article samples before bulk production so your engineering team can sign off the centerline dimensions.

Need a formal quotation? Send your Ductile Iron 90° Long Radius Elbow drawing, quantity and target price through our request for quotation form — it goes straight to the foundry inbox, and we reply with a priced offer, material certificate draft and production lead time within one business day.