C70600 Socketweld Flanges — Copper Nickel 90/10 Socket Weld Flanges
Tesco Steel & Engineering machines C70600 socketweld flanges in copper nickel 90/10 — UNS C70600, Werkstoff Nr. 2.0872, certified to ASTM B151 — for the small-bore seawater lines where ships, navies and desalination plants live: 1/2″ to 4″ NB, ASME B16.5 Class 150–1500. The pipe seats in a counterbored socket for a single external fillet weld, and the alloy's self-repairing oxide film and biofouling resistance do the rest — decades of service in salt water that pits stainless steel. Supplied with raised or flat face, navy-format laser marking, and EN 10204 3.1/3.2 certificates. ISO 9001:2015, made in Mumbai, India — exported worldwide.
UNS C70600 · 2.0872 · ASTM B151
1/2″ – 4″ NB Small-Bore
ASME B16.5 · Class 150 – 1500
SWRF & SWFF Facings
Seawater · Navy · Desalination
EN 10204 3.1 / 3.2
ISO 9001:2015 · Exported Worldwide
C70600 Copper Nickel Socket Weld Flanges — ASTM B151, 1-1/2″ Class 300, 200 PSIG CWP, From Production
What is a C70600 Socketweld Flange?
A C70600 socketweld flange is a small-bore flange machined from copper nickel 90/10 (UNS C70600 / 2.0872, to ASTM B151) with a counterbored socket that accepts the pipe end for a single external fillet weld. The socket aligns the pipe automatically and the matched bore keeps flow smooth, while the 90/10 alloy delivers what stainless cannot in salt water: no chloride pitting, no biofouling, decades of seawater service.
The pairing is no accident. Shipboard seawater systems are full of small-bore branches — cooling take-offs, firemain connections, sanitary and hydraulic lines — where butt-welding every joint would be slow and expensive. The socket weld gives each of those joints a permanent, pressure-tight fillet weld with no bevelling and no line-up clamps, and copper nickel forgives the one weakness socket joints have in stainless systems: the crevice between pipe and socket, which 90/10 Cu-Ni largely shrugs off. For larger bores and butt-welded service, see our C70600 weld neck flanges.
Installation rule: seat the pipe fully in the socket, withdraw it about 1.6 mm (1/16″), then fillet weld with 70/30 copper nickel filler (AWS ERCuNi) — no preheat, no PWHT. The gap is required by ASME B31.3; without it the cooling weld can crack at the socket root.
Also searched as: copper nickel 90/10 socket weld flange, Cu-Ni SW flange, CuNi10Fe1Mn socketweld flange, 2.0872 socket weld flange, ASTM B151 C70600 flange — all refer to the product on this page.
Chemical Composition of C70600
| Cu | Mn | Pb | Ni | Fe | Zn |
|---|
| 88.60 min | 1.00 max | 0.05 max | 9.00-11.00 | 1.80 max | 1.00 max |
Values in weight %. The iron addition hardens the protective oxide film against impingement and erosion-corrosion in flowing seawater; manganese aids workability. Full analysis of every heat appears on the mill test certificate.
Mechanical Properties of C70600
| Tensile Strength, psi | Yield Strength (0.2% offset), psi | Elongation % min. |
|---|
| 50000 | 20000 | 30 |
C70600 gains strength from cold work, not heat treatment — and its 30% minimum elongation is what lets a small-bore flanged joint absorb bolt-up, vibration and thermal movement without cracking, from cryogenic temperatures up to about 200 °C.
Equivalent Grades of C70600
| UNS | Werkstoff Nr. | Standard |
|---|
| C70600 | 2.0872 | Cu-Ni 90-10 |
Also known as CuNi10Fe1Mn (EN) and CN102 (older British specs); our flange stock is certified to ASTM B151. For the 70/30 grade (UNS C71500, 2.0882) see our C71500 socketweld flanges and copper nickel flanges pages.
C70600 Socketweld Flange Specifications
| C70600 Socket Weld Flanges are available in the following specifications: |
|---|
| Size | 1/2"NB to 4"NB (most common 1/2" to 2") |
| Class | 150#, 300#, 600#, 1500# |
| Sch (Schedule) | XS, XXS, STD & Schedule 20, 40, 80, 160 |
| Facings | Raised Face (SWRF), Flat Face (SWFF) |
| Standards | ASME B16.5, ASTM B151, EEMUA 145, navy / project drawings |
| Other Services | Pickled & passivated finish
Sand Blasting on C70600 Socket Weld Flanges
Shot Peening on C70600 Socket Weld Flanges
Navy / project-specific marking & stamping
Face protectors & seaworthy export packing |
Why C70600 for Small-Bore Seawater Joints
Seawater-Proof by Chemistry
The self-repairing cuprous oxide film keeps corrosion rates low and predictable for decades — no chloride pitting, no stress corrosion cracking, none of the stainless-in-seawater gamble.
Clean Bores, Full Flow
Marine organisms will not settle on copper nickel, so small-bore cooling and fire lines keep their design flow without dosing or rodding — and the socket weld's matched bore adds no step to foul.
Fast, Forgiving Welding
One external fillet weld with 70/30 filler, no preheat, no PWHT, no bevelling — a shipyard-friendly joint that a certified welder completes in minutes per connection.
Crevice-Tolerant Design Match
Copper nickel largely ignores the pipe-to-socket crevice that rules socket welds out of stainless seawater service — and where the spec demands zero crevice, we machine the socket for an internal seal weld.
Navy-Grade Traceability
Every flange is laser-marked with alloy, size, class, rating and heat number in navy format — exactly as photographed above — backing EN 10204 3.1/3.2 and class society certification.
Where C70600 Socketweld Flanges Are Used
Shipboard and naval small-bore systems are the natural habitat: seawater cooling branches, firemain and sprinkler take-offs, ballast and bilge connections, sanitary lines and hydraulic control piping — services where flat faced copper nickel flanges with full-face gaskets are written into the specification. Desalination plants use them on instrumentation, dosing and sampling connections around MSF and RO trains; offshore platforms on seawater utility and firewater branch lines; and coastal power stations on auxiliary cooling circuits. Wherever a small seawater line needs a permanent welded joint that will outlive the vessel or plant, C70600 socket weld is the default answer.
C70600 Socketweld Flange Dimensions
C70600 socket weld flanges follow the same ASME B16.5 dimensional tables as steel flanges of the same class — OD, thickness, bolt circle, bolting and socket bore. Full charts by class:
Price List & How to Order
Copper nickel pricing tracks the metal market, so we quote live with a stated validity rather than publish a static list. Common shipboard sizes move fast at competitive export prices. To get a firm quotation, usually within 24 hours:
1
List your requirement — size (NB), class, facing (SWRF or SWFF), pipe schedule (the socket bore is machined to suit), quantity, and the governing document (ASME B16.5 / EEMUA 145 / navy drawing).
2
Add any extras — 3.2 certification or class society witness, PMI, seal-weld preparation, project or navy marking.
C70600 Socketweld Flanges — Frequently Asked Questions
What is a C70600 socketweld flange?
It is a small-bore socket weld flange machined from copper nickel 90/10 — the alloy designated UNS C70600 (Werkstoff Nr. 2.0872), supplied to ASTM B151. The pipe end seats in a counterbored socket and is secured with a single external fillet weld, so no butt-weld fit-up is needed, while the 90/10 copper nickel body shrugs off seawater corrosion and biofouling. It is standard hardware on shipboard and naval small-bore seawater lines.
What do C70600, 90/10, 2.0872 and ASTM B151 refer to?
One alloy, several labels. C70600 is the UNS code; 90/10 is the nominal recipe — about 90% copper and 10% nickel with iron and manganese additions; 2.0872 is the German Werkstoff number; CuNi10Fe1Mn is the EN name; and ASTM B151 is the product specification our copper nickel flange stock is certified to, as laser-marked on the flanges pictured on this page. An enquiry under any of these names is quoted as the same material.
How is a C70600 socket weld flange installed?
Insert the pipe until it bottoms in the socket, withdraw it about 1.6 mm (1/16 inch) — the expansion gap required by ASME B31.3 — and run a fillet weld around the hub using 70/30 copper nickel filler (AWS ERCuNi). No preheat and no post-weld heat treatment are needed; keep heat input moderate and surfaces clean. The gap lets the pipe expand during welding so the cooling weld does not crack at the socket root.
Why use copper nickel 90/10 for small-bore seawater piping?
Because seawater is its home ground. A thin, self-repairing oxide film keeps corrosion rates low for decades, marine organisms do not settle on the copper-rich surface, and the alloy stays ductile at every marine temperature — with none of the chloride pitting risk that stainless steel carries in stagnant seawater. Small-bore cooling, firemain, sanitary and hydraulic lines on ships run almost universally on 90/10 copper nickel.
What sizes and pressure classes do C70600 socketweld flanges come in?
Socket weld is a small-bore design: 1/2 to 4 inch NB, with 1/2 to 2 inch the everyday range, in ASME B16.5 Class 150, 300, 600 and 1500. The rating follows the copper nickel material group in the B16.5 tables — the pair pictured on this page is marked 200 PSIG cold working pressure at 140 °F for 1-1/2 inch Class 300. Above 4 inch, practice shifts to butt-welded C70600 weld neck flanges, which we also manufacture.
Are C70600 socketweld flanges supplied raised face or flat face?
Both. Marine and naval specifications usually call for the flat face (SWFF) with full-face elastomer gaskets — the safe way to bolt against gunmetal and bronze valves and cast equipment — which is why the production flanges photographed on this page are flat faced. Raised face (SWRF) is supplied where process practice or the mating flange demands it. State the facing in your enquiry.
What is the chemical composition of C70600?
Copper 88.60% minimum, nickel 9.00 to 11.00%, iron up to 1.80%, manganese up to 1.00%, zinc up to 1.00% and lead no more than 0.05%. The iron addition is deliberate — it hardens the protective film against impingement and erosion-corrosion in flowing seawater. Every heat's full analysis is reported on the mill test certificate.
What are the mechanical properties of C70600 socketweld flanges?
Minimum tensile strength 50,000 psi (345 MPa), minimum 0.2% offset yield strength 20,000 psi (138 MPa) and at least 30% elongation. The alloy is not hardenable by heat treatment, and that generous ductility is exactly what a small flange sees through bolt-up, vibration and thermal movement without complaint.
When should I choose C71500 (70/30) instead of C70600?
Step up to C71500 when the seawater runs faster, hotter or dirtier than normal shipboard practice — its 30% nickel buys higher strength, a higher permitted flow velocity and better resistance in polluted harbours, at a higher price. For ordinary cooling, firemain and sanitary small-bore systems, C70600 is the standard and the economical choice. We machine socket weld flanges in both alloys.
Is the socket crevice a problem in seawater service?
Far less than it would be in stainless steel. Copper nickel does not suffer classic chloride crevice attack the way austenitic grades do, which is one reason socket weld joints remain standard marine practice for small-bore copper nickel piping. Where a specification still demands zero crevice — some navy and offshore documents do — an internal seal weld closes the gap, and we machine the socket land to suit it on request.
Which standards do you manufacture C70600 socketweld flanges to?
ASME B16.5 for the flange dimensions — Class 150 through 1500, with charts for each class linked on this page — ASTM B151 for the copper nickel material, and EEMUA 145 or navy and project drawings where the order requires them, including special socket dimensions, facings and markings. Flange OD, drilling and bolting match any other B16.5 flange of the same class.
Where are C70600 socketweld flanges used?
Shipboard and naval small-bore systems above all: seawater cooling branches, firemain and sprinkler take-offs, sanitary and grey-water lines, hydraulic and control piping. Beyond ships, they serve desalination plant instrumentation and dosing connections, offshore platform seawater utilities, and coastal power station auxiliary circuits — anywhere small-bore seawater piping needs a permanent welded joint in an alloy that ignores salt.
How are your C70600 flanges marked and traced?
Every flange is laser-marked on the rim with the full specification — as the photograph on this page shows: TESCO, ASTM-B151 UNS C70600, type and facing, size, class, pressure rating and heat number. That permanent marking carries the traceability that classification societies and naval quality systems require, from melt to installed flange.
What testing and certification do you supply with C70600 socketweld flanges?
EN 10204 3.1 mill test certificates with full chemistry and mechanicals come standard; 3.2 certification witnessed by Lloyd's, DNV, BV or TÜV is arranged for marine class work. PMI verification, dye penetrant examination and dimensional reports are available, and heat-number traceability runs unbroken from raw material to finished, marked flange.
Do you keep C70600 socketweld flanges in stock? What is the lead time?
Common shipboard sizes — 1/2 to 2 inch in Class 150 and 300 — are frequently available from stock or short production runs. Other sizes, Class 600/1500 and C71500 alloy are machined to order, typically in 3 to 5 weeks depending on quantity. Copper nickel prices track the metal market, so quotations carry a validity period; send your list for current price and delivery.
What information should I include in a C70600 socketweld flange enquiry?
Six things: size (NB), pressure class, facing (SWRF or SWFF), pipe schedule — the socket bore is machined to match the pipe — quantity, and the governing document (ASME B16.5, EEMUA 145 or your navy/project drawing). Add certification level (3.1 or 3.2, class society witness) and any marking requirements, and we return a firm quotation, usually within 24 hours.
Do you export C70600 socketweld flanges outside India?
Yes. Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer in Mumbai, shipping copper nickel flanges to shipyards, navies, desalination projects and offshore contractors across the Middle East, Europe, Africa, Southeast Asia and the Americas. Faces are protected, packing is seaworthy, and every flange arrives with stamped traceability and certificates.
