Civen Metal Material (Shanghai) Co., Ltd. is one of the leading manufacturers and suppliers of high-strength ra bronze foil in China. Welcome to buy bulk durable high-strength ra bronze foil made in China here from our factory. If you have any enquiry about cooperation, please feel free to email us.
High-Strength RA (Rolled Annealed) Bronze Foil is a cold-rolled copper-tin alloy strip engineered for applications requiring high tensile strength, bending fatigue resistance, and electrical conductivity. Unlike electrodeposited (ED) copper foil, rolled annealed bronze possesses a directional grain structure that resists cyclic fatigue under constant mechanical stress. It is supplied in coil or slit-strip form for precision stamping, chemical etching, and micro-forming.
Key Material
Alloy Grades: CuSn6 (C51900), CuSn8 (C52100), and custom phosphor bronze variants.
Chemical Composition: Tin (Sn) 5.0% - 8.5% for solid-solution strengthening; phosphorus (P) 0.03% - 0.35% for deoxidation and wear resistance.
Inclusion Control: Vacuum induction melted (VIM) raw stock restricts iron, lead, and bismuth impurities to prevent micro-voiding during ultra-thin rolling.
Performance Features
Fatigue Resistance: Withstands high-cycle dynamic bending without micro-cracking.
Electrical Conductivity: Maintained between 12% and 20% IACS across standard tempers.
Spring-Back Stability: Controlled residual stress ensures dimensional recovery after multi-axis press forming.
Corrosion Resistance: Forms a dense tin-oxide surface film that inhibits atmospheric tarnishing.
Technical Specifications
|
Parameter |
Specification Range |
Test Standard |
|
Thickness |
0.015 mm - 0.50 mm |
ISO 6892 / ASTM E345 |
|
Width |
5 mm - 650 mm (Slit edge) |
ASTM B248 |
|
Tensile Strength (Rm) |
350 - 850 MPa (Alloy/Temper dependent) |
ISO 6892-1 |
|
Elongation (delta 5) |
2% - 45% |
ISO 6892-1 |
|
Hardness |
90 - 240 HV |
ASTM E384 |
|
Surface Roughness (Ra) |
<= 0.4 um (Mirror or matte) |
ISO 4287 |
|
Camber / Bow |
< 1.0 mm per 1000 mm length |
ASTM B248 |
Manufacturing & Quality Control
Cold Reduction: Multi-high and Sendzimer rolling mills maintain thickness tolerances within +/- 1%.
Annealing: Bell-type furnaces utilize a hydrogen-nitrogen protective atmosphere to control grain size and prevent oxidation.
Slitting: Precision carbide rotary knife systems maintain edge burrs below 5% of foil thickness to prevent stamping die wear.
Inspection & Testing: 100% inline automated surface defect scanning combined with optical emission spectroscopy (OES) and universal tensile testing.
Applications
Flexible Printed Circuits (FPC)
Dynamic flex zones in electronics and automotive sensors.
Connectors & Terminals
High-insertion-force spring contacts requiring zero stress relaxation.
Shielding Gaskets
EMI/RFI shielding fingers and conductive seals.
Precision Micro-Springs
Miniature actuators for aerospace and medical instrumentation.
Customization & OEM Supply
Tempers
Available in O, 1/4H, 1/2H, H, EH, SH, or custom tensile windows.
Surface States
Mill finish, degreased, or passivated.
Edge Conditions
Mill edge, precision slit edge, or deburred round edges.
Traceability
Full Mill Test Certificates (MTC) supplied per EN 10204 3.1.
Packaging & Delivery
Coil Setup: Inner core diameters of 76 mm, 150 mm, or 300 mm (steel, aluminum, or paper cores).
Protection: Interleaved with anti-corrosion paper, wrapped in PE film, and vacuum-sealed with silica gel desiccant inside export-grade wooden crates.
Why CIVEN Metal
Mill-Direct Operations: In-house melting, rolling, annealing, and slitting ensure lot-to-lot consistency.
Precision Tolerances: Tight thickness and camber controls exceeding standard commercial ASTM requirements.
Technical Support: Direct engineering access for alloy selection and temper optimization.
FAQ
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