Civen Metal Material (Shanghai) Co., Ltd. is one of the leading manufacturers and suppliers of spring-grade ra bronze foil in China. Welcome to buy bulk durable spring-grade ra bronze foil made in China here from our factory. If you have any enquiry about cooperation, please feel free to email us.
Spring-Grade RA Bronze Foil is a cold-rolled copper-tin alloy developed for spring components that require controlled mechanical properties and electrical conductivity. Multi-stage cold rolling and controlled annealing help develop the strength, flexibility and material consistency required for precision electrical and electromechanical components.
Available in CuSn6 (C51900) and CuSn8 (C52100), the material is offered in thicknesses from 0.02 mm to 0.80 mm and widths from 5 mm to 600 mm. Custom dimensions and surface options are also available for application-specific requirements.
Key Material
Alloy Design:
The current product range includes CuSn6 (C51900) and CuSn8 (C52100) phosphor-bronze grades, with phosphorus controlled at 0.03% to 0.35%.
Metallurgical Structure:
Controlled cold rolling and annealing are used to develop a homogeneous alpha-phase structure and consistent mechanical properties across the foil.
Compliance Standards:
The current product information lists ASTM B103/B103M, EN 1654 and JIS H3110 as applicable standards for the material.
Performance Features
Elastic Limit: Withstands high bending stresses without permanent plastic deformation.
Fatigue Resistance: Resists micro-cracking under repeated reverse bending cycles.
Electrical Conductivity: Maintains 13% to 20% IACS depending on alloy grade.
Formability: Balances high spring temper with sufficient ductility for moderate radius bending.
Corrosion Resistance: Forms a dense copper-oxide and tin-oxide passivation layer.
Technical Specifications
|
Parameter |
Specification Range |
Test Standard |
|
Thickness (t) |
0.02 mm to 0.80 mm |
ISO 506 / ASTM E252 |
|
Thickness Tolerance |
+/- 0.001 mm to +/- 0.005 mm |
ISO 506 |
|
Width (w) |
5 mm to 600 mm |
Direct measurement |
|
Width Tolerance |
+/- 0.05 mm (Slitted edge) |
DIN 17745 |
|
Tensile Strength (Rm) |
550 MPa to 950 MPa |
ASTM E8 / EN ISO 6892-1 |
|
Elongation (A50) |
2% to 12% |
ASTM E8 |
|
Hardness |
160 HV to 320 HV |
ASTM E384 (Vickers) |
|
Electrical Conductivity |
13% to 20% IACS at 20 deg C |
ASTM E1004 |
|
Surface Finish |
Bright, smooth mill finish (Ra <= 0.4 um) |
ISO 4287 |
Manufacturing & Quality Control
Melting & Casting:
Vacuum induction melting and continuous casting are used to prepare the copper-tin alloy for subsequent rolling and annealing processes.
Precision Cold Rolling:
Multi-stage cold rolling is carried out on 20-high Sendzimir reversible mills with automatic gauge control and inline thickness monitoring. The current process specifies thickness variation control within ±1 μm.
Annealing:
Bell-type furnaces with protective nitrogen-hydrogen atmospheres are used for controlled heat treatment and microstructure development.
Edge Conditioning:
Precision rotary slitting with tungsten carbide tooling is used to control the foil edge condition and produce the required slit widths.
Quality Systems & Inspection:
The current production information lists ISO 9001:2015 and IATF 16949 certification, together with RoHS and REACH compliance. Inspection includes online eddy-current testing, tensile testing, microhardness testing and optical grain-size analysis.
Applications
Precision Switches
Used for snap-action switch blades and movable contact arms requiring controlled spring behavior and electrical conductivity.
Battery Springs
Suitable for terminal plates and spring contacts used in cylindrical and prismatic battery holders.
Automotive Connectors
Applicable to interconnect terminals and sensor spring clips where mechanical flexibility and electrical conductivity are required.
Telecommunications
Used for shielding fingers, grounding clips and coaxial connector springs in telecommunications equipment.
Instruments
Suitable for diaphragms, Bourdon tubes and mechanical clockwork springs requiring thin-gauge material with controlled mechanical properties.
Customization & OEM Supply
Alloy Tuning:
Tin and phosphorus ratios can be adjusted according to required electrical resistance, mechanical properties or stamping requirements.
Dimensions:
Non-standard thicknesses and slit widths can be produced according to customer drawings and application requirements.
Surface Treatments:
Available options include pre-cleaning, passivation and selective electroplating with tin, silver or nickel flash.
Coil Configuration:
The current product information lists inner diameters of 75 mm, 150 mm and 300 mm, with outer coil weights up to 500 kg. Level-wound spooling is also available.
Packaging & Delivery
Corrosion Protection
The foil is interleaved with VCI paper and vacuum-sealed in moisture-barrier polyethylene bags with desiccant gel to protect the material during storage and transportation.
Mechanical Protection
Coils are secured inside wooden crates or on steel-strapped pallets with edge protection for international shipment.
Documentation
Mill Test Certificates (MTC) according to EN 10204 3.1 are included with shipments as specified by the current product information.
FAQ
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