# UNS C61300 Aluminium Bronze Tubesheets and Forgings to ASTM B171

Registered composition limits, ASTM B171 strength minimums by thickness,
seawater behaviour, and the forged forms supplied by Jiangyin Jiangnan
Metal Co., Ltd.

Source page: https://www.steelforgepieces.com/Alloy-Steel/UNS-C61300.html
Supplier: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone: +86 189 2135 9659
Email: sales@steelforgepieces.com
Last reviewed: 18 September 2026

## C61300 at a glance

UNS C61300 is a wrought, nickel-free, single-phase alpha aluminium bronze
with a nominal composition of CuAl7Fe2.5Sn: 6.0-7.5 % aluminium,
2.0-3.0 % iron and 0.20-0.50 % tin, with copper as the remainder. It is
the standard aluminium-bronze tubesheet and seawater-plate grade of
ASTM B171.

- Ordered to ASTM B171/B171M for plate, ASTM B150/B150M for rod and bar, and ASTM B169/B169M for sheet, strip and rolled bar. The ASME code equivalent is SB-171.
- Minimum tensile strength is 520 MPa (75 ksi) for plate 50 mm and under, falling to 450 MPa (65 ksi) at 80-140 mm.
- Density 7.89 g/cm3 (0.285 lb/in3), melting point about 1040 degC (1905 degF).
- The 0.20-0.50 % tin addition is what separates C61300 from C61400. It is there to improve resistance to seawater and mildly acidic media.
- Used for condenser and heat-exchanger tubesheets, baffles, water boxes, seawater piping, desalination equipment, valve and pump internals, and marine hardware.
- Supplied by Jiangyin Jiangnan Metal Co., Ltd. as forged tubesheets, baffles, rolled rings, discs, flanges, sleeves and bars.

## What UNS C61300 is

UNS C61300 belongs to the copper-aluminium family generally called
aluminium bronze. Its structure is single-phase alpha across the full
composition range, which is the reason it stays ductile enough to cold
form and to roll or forge into large flat products. Iron at 2.0-3.0 %
acts as a grain refiner and lifts strength. Tin at 0.20-0.50 % is the
deliberate corrosion addition that gives the grade its identity.

Because there is no beta phase in the microstructure, C61300 avoids the
dealuminification mechanism that limits duplex aluminium bronzes in
long-term seawater exposure. That, plus a self-repairing alumina surface
film, is why the grade has stayed in service for decades on condenser
tubesheets, water boxes and seawater piping.

C61300 is also a nickel-free alloy. Nickel including cobalt is capped at
0.15 % as a residual rather than added, so projects that want a
nickel-aluminium bronze specify C63000 or C63200 instead.

## Chemical composition of UNS C61300

Registered UNS/CDA composition limits, the same limits adopted in
ASTM B171/B171M Table 1 and ASTM B150. Copper is the remainder rather
than a stated range.

| Element | Symbol | Content, % |
| --- | --- | --- |
| Copper (incl. silver) | Cu | Remainder |
| Aluminium | Al | 6.0 - 7.5 |
| Iron | Fe | 2.0 - 3.0 |
| Tin | Sn | 0.20 - 0.50 |
| Nickel (incl. cobalt) | Ni | 0.15 max |
| Manganese | Mn | 0.20 max |
| Silicon | Si | 0.10 max |
| Zinc | Zn | 0.10 max (A) |
| Phosphorus | P | 0.015 max |
| Lead | Pb | 0.01 max |

(A) When the product is ordered for subsequent welding and the purchaser
states this on the order, ASTM B171 further restricts chromium to 0.05 %
max, cadmium to 0.05 % max, zirconium to 0.05 % max and zinc to 0.05 %
max. Composition limits do not preclude the presence of other unnamed
elements; limits for these may be agreed between supplier and purchaser.

### The tin figure on many datasheets is wrong

Several secondary datasheets circulating online list the tin content of
C61300 as 0.02-0.05 %. That figure is a transcription error, roughly ten
times too low. The registered UNS/CDA limit and ASTM B171 Table 1 both
specify 0.20-0.50 % Sn. Since the tin addition is precisely what
distinguishes C61300 from C61400, a purchase order or an
incoming-inspection sheet written to the wrong figure will reject
conforming material, or accept the wrong alloy. Jiangyin Jiangnan Metal
Co., Ltd. certifies C61300 against the 0.20-0.50 % range.

## Mechanical properties of UNS C61300

### Guaranteed minimums to ASTM B171/B171M, M20 and O25 tempers

These are the values a C61300 plate or tubesheet must meet on test. They
fall as thickness rises, which is the number most often missed when a
tubesheet is quoted.

| Thickness | Tensile strength, min | Yield strength, min (0.5 % extension under load) | Yield strength, min (0.2 % offset) | Elongation in 50 mm, min |
| --- | --- | --- | --- | --- |
| 50 mm (2 in.) and under | 520 MPa / 75 ksi | 255 MPa / 37 ksi | 250 MPa / 36 ksi | 30 % |
| Over 50 to 80 mm (2 to 3 in.) | 485 MPa / 70 ksi | 205 MPa / 30 ksi | 195 MPa / 28 ksi | 35 % |
| Over 80 to 140 mm (3 to 5 in.) | 450 MPa / 65 ksi | 195 MPa / 28 ksi | 180 MPa / 26 ksi | 35 % |

Yield strength to ASTM B171 is the stress producing 0.5 % extension under
load, that is 0.254 mm in a 50 mm gauge length. Tension testing is to
ASTM E8/E8M. Plate thickness tolerances for C61300 are 25 % wider than
the base Table 2 tolerances; closer tolerances are achieved by surface
machining and must be agreed at order.

### Typical properties in the annealed condition

Representative values, not acceptance criteria. Use the ASTM minimums
above for design and for the purchase order.

| Property | Metric | Imperial |
| --- | --- | --- |
| Tensile strength | 540 - 600 MPa | 78 - 87 ksi |
| Yield strength | 240 - 305 MPa | 35 - 44 ksi |
| Elongation at break | 35 % | 35 % |
| Reduction of area | 25 % | 25 % |
| Hardness | about 140 HB | about 140 HB |
| Izod impact | 54 - 66 J | 39.8 - 48.7 ft-lb |
| Fatigue strength | 180 MPa | 26,100 psi |
| Modulus of elasticity | 117 GPa | 16,969 ksi |
| Shear modulus | 44 GPa | 6,380 ksi |
| Poisson's ratio | 0.34 | 0.34 |

## Physical and thermal properties of UNS C61300

| Property | Metric | Imperial |
| --- | --- | --- |
| Density | 7.89 g/cm3 | 0.285 lb/in3 |
| Melting range | about 1040 - 1110 degC | about 1905 - 2030 degF |
| Thermal conductivity at 20 degC | 56.5 W/m-K | 392 BTU-in/hr-ft2-degF |
| Coefficient of thermal expansion, 20-300 degC | 16.2 um/m-degC | 9.0 uin/in-degF |
| Electrical resistivity at 20 degC | about 15 uohm-cm | about 12 % IACS conductivity |
| Relative magnetic permeability | about 1.01 | about 1.01 |

A relative permeability close to 1.01 counts as non-magnetic for most
purposes. It is one reason C61300 is specified for naval and
minesweeping-related hardware where a low magnetic signature is required.

## Fabrication, welding and heat treatment

| Item | Value |
| --- | --- |
| Machinability rating | 30 (free-cutting brass C36000 = 100) |
| Forgeability rating | 50 (forging brass C37700 = 100) |
| Hot working | Good |
| Cold working | Good |
| Annealing temperature | 606 - 871 degC (1125 - 1600 degF) |
| Joining processes used | GTAW, GMAW, shielded metal arc welding, resistance spot, seam and butt welding, brazing |
| Not recommended | Soldering, oxyacetylene welding |

On the machine, work C61300 with positive-rake tooling, sharp edges and
generous coolant. It work-hardens if it is rubbed rather than cut. The
single-phase alpha structure takes cold reduction, forming and bending
without the cracking risk of duplex aluminium bronzes, and its hot
working behaviour is what makes large open-die tubesheets and rolled
rings practical in this grade. After annealing, follow the cooling
practice agreed for the product form.

If the plate will be welded, say so on the purchase order. ASTM B171 then
applies the restricted-residual footnote to C61300, capping chromium,
cadmium, zirconium and zinc at 0.05 % max each. Material bought without
that statement can be fully conforming and still weld badly. Jiangyin
Jiangnan Metal Co., Ltd. asks this question on every C61300 enquiry
before the melt is selected.

## Seawater and corrosion behaviour

C61300 resists seawater, brackish water, neutral and mildly acidic media
by forming a tightly adherent aluminium-oxide film. The film re-forms if
it is damaged, so the alloy tolerates higher flow velocities than the
copper-nickels and is used where water boxes, valve internals and pump
components see turbulence and entrained solids.

Two things about the structure matter over a long service life. The alloy
is single-phase alpha, so it does not contain the beta phase that makes
duplex aluminium bronzes vulnerable to dealuminification. The tin
addition also improves behaviour in the mildly acidic conditions found
under deposits and in some process streams. Where the service is highly
polluted, stagnant sulphide-bearing seawater, review the design with a
corrosion engineer. No copper alloy is immune to sulphide attack.

## Applications of UNS C61300

- Condenser, heat-exchanger and cooler tubesheets, tube plates, baffles and support plates
- Water boxes and seawater piping systems
- Desalination plant equipment and corrosion-resistant vessels
- Pressure vessels, tanks and mixing troughs where acid resistance is required
- Valve and pump components for industrial process streams, including ball valve seats
- Marine hardware, protective sheathing and ordnance components
- High-strength fasteners, tie rods and pole-line hardware
- Bearing and expansion plates for bridges and other structural applications
- Mining shovel wear components

## UNS C61300 product forms forged by Jiangnan Metal

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in
Jiangyin, Jiangsu, China. In UNS C61300 the works produces the following,
to drawing or to ASTM B171 and B150 as ordered.

| Product form | Notes |
| --- | --- |
| Tubesheets and tube plates | Front, rear, fixed, stationary and floating. Drilled and grooved to layout on request. |
| Baffles and support plates | Matched sets machined to the tubesheet drilling pattern. |
| Seamless rolled rings | Forged and ring-rolled, with no weld seam. |
| Discs, blocks and flanges | Open-die forged, rough or finish machined. |
| Sleeves, bushings and hollow bars | Trepanned or forged hollow, with the bore machined. |
| Round bars | Forged and turned, to ASTM B150 where specified. |
| Clad and weld-overlay tubesheets | C61300 cladding or overlay on a carbon or low-alloy steel backing plate, for example SA-516 Gr.70. |

Non-standard sizes and one-off tubesheets are routine. Send the general
arrangement drawing or tubesheet layout and the works will confirm
feasibility, size and lead time.

## Equivalent and related specifications

| Standard | Designation | Product form covered |
| --- | --- | --- |
| ASTM B171/B171M | C61300 | Plate, sheet and circles for pressure vessels, condensers and heat exchangers |
| ASME SB-171 | C61300 | Same scope, ASME Boiler and Pressure Vessel Code |
| ASTM B150/B150M | C61300 | Rod, bar and shapes |
| ASTM B169/B169M | C61300 | Aluminium bronze sheet, strip and rolled bar |
| ASTM B111 | C61300 | Seamless condenser tube and ferrule stock |
| ASTM B315 | C61300 | Seamless pipe and tube |
| ASTM B432 | C61300 | Copper-alloy clad steel plate |
| ASTM B608 | C61300 | Welded pipe |
| ASTM F467 / F468 | C61300 | Nuts, bolts, hex cap screws and studs |
| QQ-C-450 | C61300 | US federal specification, superseded |
| UNS | C61300 | Unified Numbering System designation, also written CDA 613 |
| BS, obsolete | CA106 | Nearest historic British designation. Verify chemistry before substituting. |

There is no exact EN equivalent to C61300. The nearest European aluminium
bronzes differ in tin and manganese, so confirm the full analysis against
ASTM B171 Table 1 before accepting a substitution.

## C61300 vs C61400 vs C63000

These three alloys appear together in ASTM B171 and are routinely
confused at enquiry stage. The short version: C61300 is the tin-bearing
seawater grade, C61400 is the general-purpose plate grade, and C63000 is
the high-strength nickel-aluminium bronze.

| Attribute | C61300 | C61400 | C63000 |
| --- | --- | --- | --- |
| Aluminium, % | 6.0 - 7.5 | 6.0 - 8.0 | 9.0 - 11.0 |
| Iron, % | 2.0 - 3.0 | 1.5 - 3.5 | 2.0 - 4.0 |
| Nickel (incl. Co), % | 0.15 max | not specified | 4.0 - 5.5 |
| Tin, % | 0.20 - 0.50 | not specified | 0.20 max |
| Manganese, % | 0.20 max | 1.0 max | 1.5 max |
| Microstructure | Single-phase alpha | Single-phase alpha | Duplex, alpha plus kappa |
| Min. tensile, plate 50 mm and under | 520 MPa / 75 ksi | 485 MPa / 70 ksi | 620 MPa / 90 ksi |
| Min. elongation, plate 50 mm and under | 30 % | 35 % | 10 % |
| Best suited to | Seawater tubesheets, water boxes, condenser plate | General condenser and heat-exchanger plate | High-strength bushings, valve stems, heavily loaded parts |

## Ordering information: what to state on the purchase order

ASTM B171 expects the following to be defined by the purchaser. Supplying
all eight items with the enquiry removes a round of questions and usually
shortens lead time by a week.

1. Copper alloy UNS number, C61300.
2. Temper: M20 (hot rolled or as forged), or O25 (annealed).
3. Dimensions. Diameter or width and length, and thickness, with the tolerance basis.
4. Whether the product will be welded in subsequent fabrication, which triggers the restricted-residual limits.
5. Whether the plate is to be machined, and on which faces.
6. Quantity and required delivery date.
7. Certification required. EN 10204 3.1 is the usual default; say if 3.2 third-party witness is needed.
8. Any supplementary testing: drilled tubesheet layout, ultrasonic examination, PMI, hardness survey, marking requirements.

## Quality and certification

Every C61300 order from Jiangyin Jiangnan Metal Co., Ltd. ships with
documentation traceable to the heat.

- Chemical analysis by optical emission spectrometry, reported against ASTM B171 Table 1 including the 0.20-0.50 % tin range.
- Tension testing to ASTM E8/E8M, with tensile, yield and elongation reported against the thickness band above.
- Hardness testing and dimensional inspection report.
- Positive material identification (PMI) on request.
- Ultrasonic examination where the product form and thickness allow it.
- EN 10204 3.1 mill certificate as standard, 3.2 with a nominated inspection agency on request.

## Frequently asked questions about UNS C61300

### What is UNS C61300?

UNS C61300 is a wrought, nickel-free, single-phase alpha aluminium bronze
with a nominal composition of CuAl7Fe2.5Sn. It contains 6.0-7.5 %
aluminium, 2.0-3.0 % iron and 0.20-0.50 % tin, with copper as the
remainder. The iron refines the grain and raises strength; the tin
improves resistance to seawater and mildly acidic media.

### Which standard covers C61300 tubesheets?

Tubesheets, tube plates and baffles in C61300 are normally ordered to
ASTM B171/B171M, Standard Specification for Copper-Alloy Plate and Sheet
for Pressure Vessels, Condensers, and Heat Exchangers. The ASME Boiler
and Pressure Vessel Code equivalent is SB-171. Rod and bar are ordered to
ASTM B150/B150M, and sheet, strip and rolled bar to ASTM B169/B169M.

### What is the tensile strength of C61300 plate?

ASTM B171 requires a minimum tensile strength of 520 MPa (75 ksi) for
C61300 plate 50 mm (2 in.) and under, 485 MPa (70 ksi) over 50 to 80 mm
(2 to 3 in.), and 450 MPa (65 ksi) over 80 to 140 mm (3 to 5 in.), in the
M20 and O25 tempers. Typical measured values in the annealed condition
are 540-600 MPa tensile and 240-305 MPa yield.

### What is the difference between C61300 and C61400?

C61300 contains a deliberate 0.20-0.50 % tin addition and a tighter
aluminium range of 6.0-7.5 %, while C61400 has no specified tin and an
aluminium range of 6.0-8.0 %. The tin in C61300 improves corrosion
resistance in seawater and mildly acidic service, and C61300 carries a
higher ASTM B171 minimum tensile strength in thin plate (520 MPa versus
485 MPa at 50 mm and under). C61400 permits up to 1.0 % manganese against
0.20 % for C61300.

### Is C61300 suitable for seawater service?

Yes. C61300 is one of the standard tubesheet and water-box materials for
seawater-cooled condensers and heat exchangers. It forms a self-healing
protective alumina film, and because it is a single-phase alpha alloy it
does not contain the beta phase associated with dealuminification in
duplex aluminium bronzes. It also tolerates higher seawater flow
velocities than the copper-nickels, which is why it is used for water
boxes, pump and valve internals and desalination equipment.

### Can C61300 be welded?

Yes. C61300 is welded by gas-shielded arc processes (GTAW and GMAW),
shielded metal arc welding, and resistance spot, seam and butt welding,
and it can be brazed. Soldering and oxyacetylene welding are not
recommended. If the plate is to be welded, say so on the purchase order:
ASTM B171 Table 1 then restricts chromium, cadmium, zirconium and zinc to
0.05 % maximum each, which improves weldability.

### Does C61300 contain nickel?

C61300 is a nickel-free aluminium bronze. Nickel including cobalt is
limited to 0.15 % maximum as a residual, not added deliberately. Projects
that require a nickel-aluminium bronze specify C63000 or C63200 instead,
which contain 4.0-5.5 % and 4.0-4.8 % nickel respectively.

### What is the correct tin content of C61300?

The correct tin range for UNS C61300 is 0.20-0.50 %. A tin range of
0.02-0.05 % appears on a number of secondary datasheets on the internet;
that figure is a transcription error and conflicts with both the
registered UNS/CDA composition limits and ASTM B171 Table 1. The tin
addition is the defining feature of C61300 against C61400, so an order
written to the wrong figure can be rejected at goods-in.

### What C61300 product forms can Jiangyin Jiangnan Metal supply?

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in
Jiangyin, Jiangsu, China. It supplies UNS C61300 as forged tubesheets,
tube plates, baffles and support plates (fixed, stationary and floating),
seamless rolled rings, forged discs and blocks, flanges, sleeves,
bushings, hollow bars and round bars, plus clad and weld-overlay
tubesheets on a steel backing plate.

### How do I request a quotation for C61300 tubesheets?

Send the drawing or tubesheet layout, the specification and temper, the
quantity and the certification required to sales@steelforgepieces.com, or
call +86 189 2135 9659. Jiangyin Jiangnan Metal Co., Ltd. is at No.1
Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province,
China.

## Request a quotation for UNS C61300

Send a drawing, a tubesheet layout, or just the grade, dimensions and
quantity. Enquiries are answered by the works, in English or Chinese.

Jiangyin Jiangnan Metal Co., Ltd., Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone: +86 189 2135 9659
Email: sales@steelforgepieces.com

## Sources and further reading

- ASTM B171/B171M, Standard Specification for Copper-Alloy Plate and Sheet for Pressure Vessels, Condensers, and Heat Exchangers. https://www.astm.org/Standards/B171.htm
- ASTM B169/B169M, Standard Specification for Aluminum Bronze Sheet, Strip, and Rolled Bar. https://store.astm.org/b0169_b0169m-20.html
- Copper Development Association, Chemical Composition of Wrought Copper Alloys: Bronzes (C50000-C69999). https://www.copper.org/resources/properties/db/datasheets/wrought-bronzes.pdf
- Copper Development Association alloy record for C61300. https://alloys.copper.org/alloy/C61300

---

Written and maintained by the technical team at Jiangyin Jiangnan Metal
Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China. Published
18 September 2026. Last reviewed 18 September 2026.

Data compiled from ASTM B171/B171M and the UNS/CDA registered composition
limits. Values are given in good faith for guidance and do not replace
the full specification or a project-specific material review.