28
Cu
Copper
%81,0–85,0
CuSn7Zn4Pb7
CuSn7Zn4Pb7 | RG7 Leaded Gunmetal / Tin-Zinc-Lead Bronze | EN 1982 CuSn7Zn4Pb7-C / CC493K
KUPTİN® R7 (CuSn7Zn4Pb7-C / CC493K) is a highly machinable leaded gunmetal with good sliding and wear properties for moderately loaded bearings, bushings, pumps and valves.
- Alloy
- CuSn7Zn4Pb7
- EN
- CuSn7Zn4Pb7-C / CC493K
- Former DIN
- G-CuSn7ZnPb / 2.1090.01
- UNS
- C93200 (comparable grade)
- ASTM
- B505/B505M; B271/B271M; B584
- Density
- 8.8 g/cm³
01. Chemical Composition (%)
50
Sn
Tin
%6,0–8,0
30
Zn
Zinc
%2,0–5,0
82
Pb
Lead
%5,0–8,0
28
Ni
Nickel
% 2.0 Max
26
Fe
Iron
%0,20 Max
15
P
Phosphorus
%0,10 Max
51
Sb
Antimon
%0,30 Max
16
S
Kükürt
%0,10 Max
13
Al
Aluminium
%0,01 Max
14
Si
Silicon
%0,01 Max
02. Mechanical Properties
| Property | Unit | Value | Test Method |
|---|---|---|---|
| Tensile Strength Rm | MPa | Sand (GS) ≥230; Permanent mould (GM) ≥230; Centrifugal (GZ) ≥260; Continuous (GC) ≥260 | EN 1982 |
| Proof Strength Rp0.2 | MPa | Sand (GS) ≥120; Permanent mould (GM) ≥120; Centrifugal (GZ) ≥120; Continuous (GC) ≥120 | EN 1982 |
| Elongation A | % | Sand (GS) ≥15; Permanent mould (GM) ≥12; Centrifugal (GZ) ≥12; Continuous (GC) ≥12 | EN 1982 |
| Hardness | HBW | Sand (GS) ≥60; Permanent mould (GM) ≥60; Centrifugal (GZ) ≥70; Continuous (GC) ≥70 | EN 1982 |
| Density | g/cm³ | approx. 8.8 | Typical value |
03. Applications
- Moderately loaded plain bearings
- Bronze bushings and bearing sleeves
- Guide bushings
- Hydraulic-cylinder guides
- Pump housings and impellers
- Valve bodies and gate components
- Slideways and wear plates
- Thrust and sliding components
- General machine components
- Special castings made to drawing
04. Manufacturing Technology and Supply Forms
Manufacturing TechnologySand, permanent-mould, centrifugal, continuous and project-specific casting; the process is selected according to product form, dimensions, geometry, mechanical requirements, service conditions and the order specification.
Supply FormsCustom Casting, Hollow Bar / Pipe, Flat Bar / Plate, Round Bar
05. Standards and Comparable Grades
06. Technical Description
View Detailed Technical Description
What Is CuSn7Zn4Pb7?
CuSn7Zn4Pb7, commonly known as RG7, is a copper-based leaded gunmetal casting alloy containing tin, zinc and lead. Its EN 1982 cast-product designation is CuSn7Zn4Pb7-C, material number CC493K. Tin contributes strength and wear behaviour, zinc assists castability, and lead improves machinability, conformability and the ability to embed small foreign particles.
Chemical Composition
Under EN 1982, the total Cu + Ni content is 81.0-85.0%, Sn is 6.0-8.0%, Zn is 2.0-5.0% and Pb is 5.0-8.0%. Maximum limits are 2.0% Ni, 0.20% Fe, 0.10% P and S, 0.30% Sb, and 0.01% each Al and Si. The principal copper value in the standard is Cu + Ni, not Cu alone. Detailed values are shown in Section 01, Chemical Composition.
Mechanical and Typical Physical Properties
EN 1982 minimum values are: sand casting (GS), Rm 230 MPa, Rp0.2 120 MPa, A 15% and 60 HBW; permanent-mould casting (GM), 230 MPa, 120 MPa, 12% and 60 HBW; centrifugal casting (GZ), 260 MPa, 120 MPa, 12% and 70 HBW; continuous casting (GC), 260 MPa, 120 MPa, 12% and 70 HBW. Mechanical values must be assessed separately by casting process.
Typical values are approximately 8.8 g/cm³ density, 0.356 J/(g·K) specific heat, 18-18.5 × 10⁻⁶/K thermal expansion, 47-64 W/(m·K) thermal conductivity and 7.5 MS/m electrical conductivity. These are not guaranteed EN 1982 values; they are typical references that can vary with production condition and measurement method.
Properties and Applications
CuSn7Zn4Pb7 offers good sliding and bearing behaviour, wear resistance, very good machinability, conformability and suitable corrosion performance. Applications include moderately loaded plain bearings, bronze bushings and bearing sleeves, guide bushings, hydraulic-cylinder guides, pump housings and impellers, valve components, slideways, wear plates and general machine parts.
The lead content does not make the alloy inherently self-lubricating. Although it can provide relative tolerance to temporary lubrication deficiency, lubricant selection must be evaluated together with load, speed, counterface, operating clearance and temperature. Seawater and brine applications require consideration of flow velocity, temperature, galvanic coupling and service environment. For contact with drinking water, applicable regulations, lead-release limits and required product approvals must be verified separately.
Production and Supply Forms
KUPTİN® R7 can be produced by sand, permanent-mould, centrifugal, continuous and project-specific casting. The process is selected according to product form, dimensions, geometry, mechanical requirements, service conditions and the order specification.
The alloy can be supplied as round bar, bronze bushing, tube, hollow or solid component, ring, flat bar, plate and special casting to drawing. Final dimensions, tolerances and machining allowances should be reviewed before ordering.
Standards and Comparable Grades
The principal European cast-product designation is CuSn7Zn4Pb7-C / CC493K under EN 1982. CuSn7Zn4Pb7-B / CB493K is the related ingot designation and must not be treated as the cast-product grade.
Former DIN 1705 designations are G-CuSn7ZnPb / 2.1090.01, GZ-CuSn7ZnPb / 2.1090.03 for centrifugal casting and GC-CuSn7ZnPb / 2.1090.04 for continuous casting. GB-CuSn7ZnPb / 2.1091 is the former ingot designation under DIN 17656.
UNS C93200 / SAE 660 is a comparable US grade, not an exact equivalent because its chemical-composition limits differ from CuSn7Zn4Pb7-C. ASTM B505/B505M covers continuous-cast, ASTM B271/B271M centrifugal-cast and ASTM B584 sand-cast copper-alloy products. ASTM numbers are product specifications, not alloy names, and must be stated together with the selected UNS grade and product form. Conflicting public cross-reference data for BS, JIS and historical ISO designations have been excluded from the verified main table.
Technical Note
EN 1982:2024 is the current principal standard. Mechanical properties are minimum references for the relevant casting process; values in a final component can vary with section size and casting structure. Chemical, mechanical and physical information is provided for general technical guidance. Final product properties must be confirmed against the order specification, casting process, section size, dimensions, tolerances, product analysis certificate and quality-control results.