Brass & Copper Parts India, based in Jamnagar, India, is a specialist manufacturer of LG2 bronze castings — one of the most widely specified copper casting alloys in the world for plumbing, steam, marine, and industrial pressure hardware. We supply LG2 bronze castings in sand cast, centrifugal cast, and investment cast forms to US manufacturers, distributors, valve OEMs, and engineering companies.
What Is LG2 Bronze?
LG2 is a Leaded Gunmetal bronze alloy designation per British Standard BS 1400. It is one of the most important and widely used copper casting alloys globally, known by many names and specifications across different countries:
- LG2 — British Standard designation (BS 1400)
- Gunmetal 85-5-5-5 — Popular trade name indicating nominal composition
- C83600 — ASTM / UNS designation (USA)
- Red Brass — Common US trade name
- CC491K — European Standard EN designation
- ASTM B62 — Standard specification for composition bronze (85-5-5-5)
Chemical Composition of LG2 Bronze
| Element | Nominal % | Permissible Range (ASTM B62) | Role |
|---|---|---|---|
| Copper (Cu) | 85% | 84.0–86.0% | Base metal; provides conductivity and corrosion resistance |
| Tin (Sn) | 5% | 4.0–6.0% | Strengthens matrix; improves pressure tightness |
| Lead (Pb) | 5% | 4.0–6.0% | Fills micro-porosity; improves machinability and pressure tightness |
| Zinc (Zn) | 5% | 4.0–6.0% | Improves fluidity; assists casting fill |
| Nickel (Ni) | — | max 1.0% | Minor impurity |
| Iron (Fe) | — | max 0.3% | Minor impurity |
| Antimony (Sb) | — | max 0.25% | Minor impurity |
LG2 Bronze Properties
| Property | Value (Typical) | Standard |
|---|---|---|
| Tensile Strength | 255 MPa (37 ksi) | ASTM B62 |
| Yield Strength (0.2% proof) | 117 MPa (17 ksi) | ASTM B62 |
| Elongation | 30% minimum | ASTM B62 |
| Brinell Hardness | 60–75 HB | — |
| Density | 8.83 g/cm³ | — |
| Electrical Conductivity | ~15% IACS | — |
| Thermal Conductivity | 71 W/m·K | — |
| Max. Service Temperature | 260°C (500°F) | — |
| Machinability Rating | 90% (vs. free-cutting brass) | — |
LG2 Bronze International Grade Equivalents
| Standard | Designation | Country/Region |
|---|---|---|
| ASTM B62 / UNS | C83600 | USA |
| BS 1400 | LG2 | UK |
| EN 1982 | CC491K (CuSn5Pb5Zn5) | Europe |
| DIN 1705 | RG5 (Rotguss 5) | Germany |
| ISO 1338 | CuSn5Pb5Zn5 | International |
| JIS H 5111 | CAC402 | Japan |
| IS 318 | Grade 2 Gunmetal | India |
| AS 1565 | C83600 (adopted UNS) | Australia |
LG2 Bronze Casting Products We Manufacture
LG2 Bronze Valve Bodies and Bonnets
Sand cast and machined LG2 bronze valve bodies for gate valves, globe valves, check valves, and ball valves in ANSI Class 125 and Class 250 pressure ratings. All valve castings are hydrostatically tested per MSS SP-70/SP-71 before dispatch.
LG2 Bronze Pipe Fittings and Flanges
Screwed and flanged bronze fittings to ASME/ANSI B16.15 (Class 125 and 250 cast bronze), including elbows, tees, crosses, couplings, nipples, and reducing bushings. Flanged fittings per ASME B16.24.
LG2 Bronze Pump Components
Pump casings, impellers, wear rings, and seal plates cast in LG2 bronze for centrifugal pumps used in water supply, HVAC, marine, and industrial process applications.
LG2 Bronze Steam Fittings
High-pressure steam fittings including unions, nipples, elbows, and valves rated for steam service up to 260°C (500°F). LG2’s excellent pressure tightness makes it the standard alloy for steam condensate and LP steam hardware.
LG2 Bronze Electrical Hardware
Power distribution hardware including hotline clamps, parallel groove connectors, ground rod clamps, and electrical box fittings cast from LG2 / C83600 gunmetal bronze.
Why Choose Brass & Copper Parts India for LG2 Bronze Castings?
- Certified alloy compliance: LG2 / C83600 castings with spectrographic analysis and ASTM B62 mill certs
- Multiple casting processes: Sand casting, centrifugal casting, and investment casting under one roof
- Pressure tightness: All pressure-rated castings hydrostatically tested as standard
- CNC machining in-house: Complete cast-and-machine supply from one source
- ASME/ANSI compliance: Valve and fitting castings designed to ASME B16.15, B16.24, MSS SP-70
- US MRO distribution: Stock programs available for US valve and pump OEM distributors
- Cost savings: 35–50% vs. North American and European castings foundries
Frequently Asked Questions — LG2 Bronze Casting
Q1: What is LG2 bronze and what are its key properties?
LG2 bronze (BS 1400 LG2, UNS C83600, EN CC491K) is a leaded tin bronze also known as gunmetal, with a nominal composition of 85% copper, 5% tin, 5% zinc, and 5% lead. Key properties: tensile strength 230 to 280 MPa, elongation 13 to 18%, hardness 70 to 85 HB, electrical conductivity approximately 15% IACS, and excellent pressure tightness. It is the most widely used cast bronze alloy for valves, pumps, marine hardware, and bearing bushes.
Q2: What is the difference between LG2 and gunmetal 85-5-5-5?
LG2 and gunmetal 85-5-5-5 are the same alloy described by different naming conventions. LG2 is the British Standard (BS 1400) designation; gunmetal is the common industry term used globally; 85-5-5-5 describes the nominal percentage composition (85 Cu, 5 Sn, 5 Pb, 5 Zn); UNS C83600 is the ASTM designation; CC491K is the EN ISO 1982 designation. All describe the same cast bronze with approximately the same chemistry and properties.
Q3: Is LG2 bronze suitable for pressure-retaining castings?
Yes. LG2 bronze is specifically valued for its pressure tightness — very low gas porosity and shrinkage porosity in sand and die castings make it suitable for valve bodies, pump housings, and pipe fittings carrying water, steam, oil, and gas at pressures up to 17 bar (250 psi) at temperatures up to 290 degrees Celsius. Pressure testing per ASTM B62 or ASME Section VIII requirements is available on all pressure-retaining castings.
Q4: What casting processes are available for LG2 bronze?
We offer: sand casting (for complex shapes, large parts, and low to medium volumes with CT8 to CT10 dimensional accuracy), gravity die casting (for medium to high volumes needing better surface finish CT6 to CT7 and tighter dimensions), lost wax investment casting (for very high precision, thin walls, and excellent surface finish CT4 to CT6), and continuous casting of bar and tube. Most LG2 valve bodies are produced by sand or gravity die casting.
Q5: What ASTM standard covers LG2 bronze castings?
ASTM B62 covers leaded tin bronze castings (C83600 LG2) for general service — the most commonly referenced US standard for LG2 valve and fitting castings. ASTM B271 covers centrifugal castings, ASTM B584 covers copper alloy sand castings for general applications. For UK and European projects, BS EN 1982 (CC491K) is the relevant standard. We supply Material Test Certificates per the applicable standard with all production castings.
Q6: Can LG2 bronze castings be used in potable water systems?
Standard LG2 bronze with 5 percent lead does not meet NSF/ANSI 372 low-lead requirements (maximum 0.25 percent weighted average lead content) required by the US Safe Drinking Water Act amendments and California AB 1953 for potable water contact surfaces. For potable water applications, low-lead or lead-free bronze alloys such as C89833 (BiLock) or C87850 (silicon-zinc bronze) should be specified. We can cast in these NSF 372-compliant alloys.
Q7: What machining operations are performed on LG2 bronze castings?
After casting, LG2 bronze castings undergo: rough turning to remove casting skin and establish datum surfaces, bore machining to final pipe thread specification (NPT, BSP, or metric), thread cutting (external and internal), port drilling and cross-drilling for multi-port manifolds, seat grinding for valve seating surfaces, and surface finishing to required Ra. LG2 is excellent to machine with high-speed steel and carbide tooling, achieving Ra 1.6 micron as-turned.
Q8: What non-destructive testing do you perform on LG2 castings?
Available NDT methods include: liquid penetrant testing (LPT) per ASTM E1417 for surface cracks, radiographic testing (X-ray or gamma ray) per ASTM E94 for internal porosity and inclusions in pressure-critical castings, hydraulic pressure testing at 1.5x to 2x working pressure, and dimensional inspection on CMM or optical comparator. Test reports are provided with each batch for pressure vessel and critical application castings.
Q9: What is the shrinkage allowance for LG2 bronze in sand casting?
LG2 bronze has a volumetric shrinkage of approximately 1.6 to 1.8 percent during solidification. For linear dimensions, a pattern allowance of approximately 1.3 to 1.5 percent (13 mm per 1000 mm) is applied in the pattern design to account for both liquid and solid shrinkage. Additional machining stock of 2 to 5 mm is added to all machined surfaces. We design patterns with these allowances built in.
Q10: What minimum order quantity applies to LG2 bronze castings?
Sand castings: minimum 5 to 10 pieces for new pattern development orders; 25 pieces for repeat orders on existing patterns. Gravity die castings: minimum 50 pieces for new die development; 100 pieces for repeat production on existing dies. Investment castings: minimum 25 pieces for wax tooling development; 50 pieces repeat. Rush orders of 1 to 5 sample castings can be produced for design validation at prototype pricing.
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