C71500 Slip On Flanges — 70/30 Copper Nickel Manufacturer
Tesco Steel & Engineering manufactures 70/30 copper-nickel slip on flanges — UNS C71500, Werkstoff 2.0882, CuNi30Mn1Fe — from certified ASTM B151 rod and B171 plate to ASME B16.5 dimensions, ½″ to 24″ NB, with EN 1092-1 and EEMUA 145 patterns to order. The heavy-duty cupronickel: three times the nickel of 90/10 C70600 buys ~25% more strength, tolerance of faster seawater (~4–4.5 m/s) and the hot-brine capability that desalination high-temperature stages and naval systems specify — while keeping the family's biofouling resistance and chloride SCC immunity. Machined, inspected and XRF PMI-verified in-house, as pictured below. EN 10204 3.1/3.2 MTC. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
CuNi 70/30 · C71500 · 2.0882ASTM B151 / B171 · CuNi30Mn1FeNi 29–33% · Fe 0.4–1.0%ASME B16.5 · EN 1092-1 · EEMUA 145½″ – 24″ NB · FF & RFHot Brine & High-Velocity SeawaterEN 10204 3.1 / 3.2 · ISO 9001:2015
Copper Nickel Slip On Flanges — Individually Wrapped & Crated for Export
What is a C71500 Slip On Flange?
C71500 = the cupronickel for the hard cases.70% copper, 30% nickel (CuNi30Mn1Fe / 2.0882): ~25% stronger than 90/10, comfortable at ~4–4.5 m/s seawater where 90/10 stops at ~3.5, and built for hot concentrated brine — the desalination hot-stage and naval-system grade — while keeping cupronickel's biofouling resistance and chloride SCC immunity. Machined from ASTM B151 rod to ASME B16.5 dimensions, usually flat face with a CWP rating. As a slip-on: two fillet welds with ERCuNi filler — the same 70/30 wire that welds the whole family.
Also searched as: CuNi 70/30 slip on flange, cupro nickel 70/30 slip on flange, copper nickel 70-30 SORF flange, ASTM B151 C71500 flange, CuNi30Mn1Fe / 2.0882 slip on flange, EEMUA 145 flange — all refer to the product on this page. See also our 70/30 cupro nickel flanges overview and UNS C71500 flanges.
Rule of thumb:90/10 is the seawater default; 70/30 is what the specification escalates to when velocity, temperature or load exceed it — and C71640 when sand joins the party.
C71500 (CuNi 70/30) Chemical Composition
Cu
Ni
Fe
Mn
Zn
Pb
Remainder (~67%)
29.0-33.0
0.40-1.0
1.0 max
0.5 max
0.02 max
Values in weight % for UNS C71500. Note the iron runs lower than 90/10's (0.40–1.0 vs 1.0–1.8) — with three times the nickel doing the film-strengthening work, less iron is needed. 70/30 and 90/10 stock are indistinguishable by eye, which is why the XRF PMI pictured below is standard practice on every lot.
C71500 Mechanical Properties
Grade
Tensile Strength, MPa (ksi)
Yield Strength 0.2%, Min, MPa (ksi)
Elongation % min
CuNi 70/30 (this page)
345 (50) min
120 (18) min
30
CuNi 90/10 — for comparison
275 (40) min
105 (15) min
30
Annealed condition, density 8.94 g/cm³. Roughly 25% stronger than 90/10, and the advantage grows at temperature — the property that earns 70/30 the desalination hot stages. Cu-Ni flanges carry CWP pressure ratings on B16.5 dimensions rather than steel class ratings. Values demonstrated per lot on the EN 10204 certificate.
C71500 Slip On Flange Specifications
70/30 Copper Nickel Slip On Flanges are available in the following specifications:
Offshore projects widely cite EEMUA 144 (pipe), 145 (flanges) and 146 (fittings); naval paperwork may reference MIL-C-15726 / MIL-T-16420. Not an A182 or B564 material — cupronickel has its own copper-alloy B-series family. Sand-resistant sister: C71640.
Why C71500 Slip Ons Are Specified
The Escalation Grade
When 90/10's window closes — velocity past 3.5 m/s, brine running hot, loads climbing — 70/30 is the same trusted chemistry with the margins widened.
Desalination's Hot-Stage Alloy
MSF high-temperature stages and brine heaters concentrate hot chloride brine — 70/30 keeps its film and its strength where 90/10 fades and stainless cracks.
Naval Pedigree
Submarine and warship seawater systems at elevated pressure standardised on 70/30 decades ago — strength plus SCC immunity plus fouling resistance in one alloy.
Still a True Cupronickel
Biofouling resistance and chloride SCC immunity carry over from the family — and one ERCuNi welding procedure covers both 70/30 and 90/10 on site.
Don't pay for nickel the duty doesn't need. Nickel is the expensive ingredient, and for the great majority of seawater systems — firewater mains, cooling water at ordinary velocity and temperature — 90/10 is fully adequate and slightly better against biofouling. Specify 70/30 for what it uniquely buys: velocity above ~3.5 m/s, hot concentrated brine, higher mechanical load. State the design velocity and temperature on the enquiry and we confirm the honest grade — we machine both from the same works.
How Our C71500 Slip On Flanges Are Made — In Pictures
1
Certified stock — ASTM B151 rod / B171 plate of certified C71500 heats, full traceability from mill certificate to despatch.
2
CNC turning & drilling — faces, hub and bore turned on CNC lathes, bolt holes machined on vertical machining centres — both pictured below.
3
Facing — flat face (the Cu-Ni default) or raised face with serrated finish per the piping class.
4
Dimensional inspection — bore, thickness, bolt circle and facing checked against ASME B16.5 / EEMUA 145 — calipers on the shop floor, pictured below.
5
PMI & marking — XRF verification separating 70/30 from 90/10 beyond doubt, then permanent laser marking of standard, grade, size, class, CWP rating and heat number.
6
Certification & packing — EN 10204 3.1 MTC (3.2 witnessed on request), individually wrapped and crated as pictured above.
Production Gallery — Copper Nickel Flanges at Our Works
Bolt-Hole Drilling on the VMCFace & Bore Turning on the CNC LatheBore Inspection — Digital CaliperThickness Check Against B16.5XRF PMI — Separating 70/30 From 90/10 Beyond Doubt
Where C71500 Slip On Flanges Are Used
The hot and hard-working end of seawater engineering: desalination plant high-temperature stages and brine heaters, naval and submarine seawater systems at elevated pressure, high-velocity cooling mains, condenser and heat-exchanger interconnections running hot, and offshore systems where the design brief exceeded 90/10 — plus everything 90/10 does, where the project standardises on one grade.
C71500 Slip On Flange Dimensions
Cu-Ni slip-on dimensions follow the ASME B16.5 slip-on tables (with CWP ratings) — identical dimensions for every material. Full charts by class:
Example: “Slip On Flange, 3″ NB, ASME B16.5 #300 pattern, FF, CuNi 70/30 / ASTM B151 (C71500), EN 10204 3.1 — 20 pcs.” Quotations normally within 24 hours with price, unit weight and delivery.
C71500 Slip On Flanges — Frequently Asked Questions
What is a C71500 slip on flange?
It is a slip-on flange made from 70/30 copper-nickel — UNS C71500, Werkstoff 2.0882, CuNi30Mn1Fe — to ASME B16.5 dimensions, slid over the pipe end and secured with two fillet welds. 70/30 is the heavy-duty member of the cupronickel family: three times the nickel of 90/10 buys higher strength, tolerance of faster-flowing seawater and hot-brine capability, while keeping the family's signature virtues — biofouling resistance and complete immunity to chloride stress corrosion cracking.
What is 70/30 copper nickel?
A copper-base alloy carrying roughly 30% nickel with controlled iron and manganese — the stronger, hotter-duty sibling of 90/10. The extra nickel stiffens the protective film and the metal itself, which is why navies specify it for demanding seawater systems and desalination plants use it in their hottest stages. Designations: UNS C71500, Werkstoff 2.0882, EN CuNi30Mn1Fe, CuNi 70/30 — flange stock is supplied to ASTM B151 (rod) and B171 (plate).
What is the chemical composition of C71500?
Copper is the balance, with nickel 29.0-33.0%, iron 0.40-1.0%, manganese 1.0% max, zinc 0.5% max and lead 0.02% max. Note the iron runs lower than in 90/10 — with three times the nickel doing the film-strengthening work, less iron is needed. XRF PMI verification, as pictured on this page, confirms the analysis on every lot; distinguishing 70/30 from 90/10 stock by eye is impossible, so the instrument matters.
What are the mechanical properties of C71500 slip on flanges?
In the annealed condition: tensile strength 345 MPa (50 ksi) minimum, 0.2% yield strength 120 MPa (18 ksi) minimum and elongation 30% minimum, with density 8.94 g/cm³ — roughly 25% stronger than 90/10, with the advantage growing at elevated temperature, where 70/30 keeps useful strength well past the point 90/10 fades. Values are demonstrated per lot on the EN 10204 certificate.
When is 70/30 specified instead of 90/10?
When the duty exceeds 90/10's comfortable window in any of three directions. Velocity: seawater designed to flow faster than about 3.5 m/s moves to 70/30's higher limit. Temperature: hot brine and the high-temperature stages of desalination plants favour 70/30's retained strength and film stability. Load: naval and submarine systems at higher pressure use the stronger alloy. Everywhere else, 90/10 remains the economic default — that is the whole architecture of the cupronickel family.
What velocity can C71500 handle?
Design practice allows 70/30 roughly 4 to 4.5 m/s in normal pipe sizes — usefully above 90/10's ~3.5 m/s — because the nickel-richer protective film resists impingement better. The same lower bound applies: keep water moving (roughly 1 m/s minimum) to discourage deposits. Where sand-laden intake water pushes erosion beyond even 70/30, the 2% iron, 2% manganese variant C71640 is the family's final step.
Why do desalination plants use 70/30 in the hot stages?
Multi-stage flash desalination concentrates hot brine — among the most aggressive chloride environments in industry — and stage temperatures climb past what 90/10 handles gracefully. 70/30 keeps its strength and its protective film at these temperatures, resists the concentrated brine, and stays immune to the chloride stress corrosion cracking that rules out ordinary stainless. The classic MSF plant split: 90/10 for the cooler stages and large water lines, 70/30 for the hot stages and demanding evaporator duty.
How does C71500 compare with Monel 400?
They are neighbours on a continuum: 70/30 copper-nickel is Cu-30Ni; Monel 400 is Ni-30Cu. Monel's nickel majority gives roughly another 40% strength, superior cavitation resistance, and hydrofluoric acid and caustic capability — at a distinctly higher price and with most of the biofouling resistance lost. C71500 remains the piping and flange alloy; Monel takes the pumps, shafts and hardware. When an enquiry sits between them, the deciding questions are usually strength and budget.
Does 70/30 resist biofouling like 90/10?
Yes, though marginally less strongly — the effect scales with copper content, and 70/30 carries about 20% less copper than 90/10. In practice both grades keep seawater lines substantially free of barnacles, mussels and algae for decades, and both decisively outperform steel, stainless, titanium and FRP, which foul freely. Where biofouling is the single dominant requirement — firewater ring mains above all — 90/10's higher copper gives it the edge; where strength or heat dominate, 70/30's small sacrifice is well spent.
Why are copper nickel flanges often flat face?
Copper alloys sit outside the steel rating tables of ASME B16.5, so Cu-Ni flanges are made to B16.5 dimensions and assigned a cold working pressure (CWP) rating instead of a steel class rating. And seawater systems frequently mate copper-nickel to composite (GRE) piping and cast fittings, where a flat face with a full-face gasket loads the joint evenly and protects the weaker mating flange. Raised face is equally available where the piping class calls for it — state the facing on the enquiry.
Which ASTM standards cover C71500 slip on flanges?
Copper-nickel flanges are machined from certified wrought stock: ASTM B151 rod and bar or ASTM B171 plate, with dimensions to ASME B16.5 and patterns to EN 1092-1 or EEMUA 145 for offshore projects. System partners are ASTM B466 seamless and B467 welded pipe and EEMUA 146 or ASTM B366 fittings; naval procurement may cite MIL-C-15726 or MIL-T-16420 equivalents. Not an A182 or B564 material — cupronickel has its own copper-alloy B-series family.
How is a C71500 slip on flange welded to pipe?
With two fillet welds — hub outside, bore inside, pipe set back 1/8" (3 mm) — using copper-nickel filler ERCuNi, which is itself a 70/30 composition: matching filler for this grade, and the same wire that welds 90/10, so one qualified procedure covers the whole cupronickel family. No preheat and no post-weld heat treatment; copper's thermal conductivity asks for slightly higher heat input than steel practice and scrupulously clean, lead-free joints.
Where are C71500 slip on flanges typically used?
The hot and hard-working end of seawater engineering: desalination plant high-temperature stages and brine heaters, naval and submarine seawater systems at elevated pressure, high-velocity cooling mains, condenser and heat-exchanger interconnections running hot, and offshore systems where the design brief exceeded 90/10. Alongside these, everything 90/10 does — firewater, cooling, brackish service — 70/30 also does, at a price premium that buys its extra margin.
What sizes and classes are C71500 slip on flanges available in?
From ½" to 24" NB to ASME B16.5 dimensions in Class 150 and 300 patterns (CWP-rated), with EN 1092-1, EEMUA 145 and larger diameters machined to order — the CNC machining and inspection pictured on this page show our in-house route from certified stock to finished flange. Copper-nickel is project material machined against the order, normally dispatching within a few weeks with EN 10204 3.1 certification; state the required delivery on the enquiry and we confirm the schedule with the quotation.
Who manufactures C71500 slip on flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, machining 70/30 copper-nickel / UNS C71500 slip on flanges from ½" to 24" NB from ASTM B151 and B171 certified stock to ASME B16.5, EN 1092-1 and EEMUA 145 patterns — alongside the full C71500 range of weld neck, blind, socketweld, threaded, lapped joint and spectacle blind flanges, plus 90/10 C70600 and sand-resistant C71640 — with in-house CNC machining, dimensional inspection, XRF PMI verification and EN 10204 3.1/3.2 certification on every lot, as pictured on this page. Exported to more than 50 countries.
