Copper brazing rod is a copper–zinc alloy–based filler metal optimized with additions of iron, manganese, and silicon to enhance mechanical properties. It offers excellent cross-material compatibility and delivers high-strength, dense overlay performance.
Cross-Material Compatibility:
Enables joining of copper (brass, pure copper), low-carbon steel, gray cast iron, and selected copper alloys, overcoming the “single-material limitation” of traditional welding rods.
High-Strength Overlay:
Tensile strength up to 400 N/mm² and Brinell hardness of 100 HB.
The welded joint shows excellent wear and crack resistance, extending service life by 30%.
Low-Splash Process:
Silicon addition suppresses zinc evaporation, reducing spatter by 50% and post-weld cleaning time by 40%.
Wide Process Adaptability:
Solidus at 870°C and liquidus at 890°C, suitable for oxy-acetylene and TIG brazing.
Offers great flexibility for different process conditions.
Specification
| Class | Alloy | Cu | Al | Fe | Mn | Ni | Pb | Si | Sn | Zn | Other |
| Cu6800 | CuZn40Ni | 56.0–60.0 | 0.01 | 0.25–1.2 | 0.01–0.5 | 0.2–0.8 | ≤0.05 | 0.04–0.2 | 0.8–1.1 | Bal. | ≤0.5 |
| SCu6800 | CuZn40Ni | 56.0–60.0 | ≤0.01 | 0.25–1.2 | 0.01–0.5 | 0.2–0.8 | ≤0.05 | 0.04–0.15 | 0.8–1.1 | Bal. | ≤0.5 |
| Cu6800 | CuZn40Ni | 56.0–60.0 | 0.01 | 0.2–1.2 | 0.5 | 0.2–0.8 | ≤0.05 | 0.2 | 0.8–1.1 | Bal. | ≤0.2 |
| Cu6800 | RBCuZn-B | 56.0–60.0 | 0.01 | 0.25–1.2 | 0.01–0.5 | 0.2–0.8 | ≤0.05 | 0.04–0.2 | 0.8–1.1 | Bal. | ≤0.5 |
（All data are typical values based on AWS A5.8 RBCuZn-B standard.）
Fe + Mn: Form Fe–Mn intermetallic compounds, increasing hardness from 40 HB (pure copper) to 100 HB, improving wear resistance.
Zn: Lowers melting point (from 1083°C to 870–890°C) and enhances fluidity; excessive Zn may cause porosity, which is mitigated by Si addition.
Si: Forms Zn–Si compounds to reduce zinc vaporization, achieving a low-splash effect. Optimal Si range: 0.04–0.2% (excess may cause brittleness).
Ni: Refines grain structure and enhances crack resistance, particularly beneficial for cast iron brazing. Optimal range: 0.2–0.8%.
Physical and Mechanical Properties
| Property | Value |
| Solidus Temperature | 870°C |
| Liquidus Temperature | 890°C |
| Density | 8.4 kg/dm³ |
| Tensile Strength | 400 N/mm² |
| Elongation | 25% |
| Brinell Hardness | 100 HB |
Application
Mechanical Manufacturing
Joining copper alloy bearing seats with steel housings in gearboxes.
Customer Benefit: One-step brazing without cracking, assembly efficiency improved by 25%.
Mold Repair
Edge rebuilding of carbide molds (e.g., stamping or injection molds).
Process Requirement: Preheat at 450°C, short heating cycles; post-braze hardness 95–105 HB, significantly extending mold life
Pipeline Engineering
Dissimilar brazing of brass water pipes to steel flanges (pressure ≤ 1.6 MPa).
Advantage: Argon-shielded brazing ensures leak-free joints with 98% first-pass pressure test success.
Machine Tool Maintenance
Repair of gray cast iron guide rails (wear depth ≤ 3 mm).
Result: Preheat to 350°C, weld surface flatness deviation ≤ 0.05 mm, achieving accuracy comparable to new components.
