C51000 Phosphor Bronze

C51000 Phosphor Bronze

94.2–95.8%
Copper Content
4.2–5.8%
Tin Content
0.03–0.35%
Phosphorus Content
C51000 phosphor bronze is a high-performance copper-tin alloy offering excellent fatigue resistance, spring properties, corrosion resistance, and wear resistance. It is widely used in electrical connectors, springs, switch components, and precision engineering applications.
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Lead Time: 3-5 Business Days

Product Overview

C51000 phosphor bronze is a copper-tin alloy containing approximately 5% tin with a controlled addition of phosphorus to enhance strength, wear resistance, and fatigue performance. It is manufactured to ASTM B103, ASTM B139, and related standards for demanding electrical and mechanical applications.

Produced through rolling, drawing, and precision heat treatment processes, C51000 bronze offers excellent elasticity, dimensional stability, and corrosion resistance. Its superior spring characteristics and reliable conductivity make it one of the most widely used phosphor bronze alloys worldwide.

C51000 phosphor bronze is extensively used in electrical connectors, relay springs, switch contacts, precision stampings, and industrial components where fatigue resistance and durability are critical. It is widely applied across electronics, telecommunications, automotive, aerospace, and industrial manufacturing industries.

Key Features

Excellent fatigue resistance
Outstanding spring performance
Good wear resistance
High corrosion resistance
Reliable electrical conductivity
Excellent formability and stampability

Available Sizes

Copper Shape Thickness (mm) Width/Diameter (mm) Length (m)
Bar - Φ5-200 1-6
Wire - Φ0.05-10 Customize
Sheet 0.25-6 500-2500 1-6
Plate 6-200 200-3000 1-6
Strip 0.15-6 8-610 Customize
Tube OD: φ2-600; WT:φ0.2-100mm - 1-6
Coil 0.15-6 3-1250 1-6
Foil < 0.15 10-1350 Customize
Profile Customized Customize Customize

* Custom sizes available upon request. Contact our sales team for special requirements.

Technical Specifications

Precision data for engineering decisions. All values tested per ASTM standards.

01 Material Properties

Specification Value Notes
Cu Content 94.2–95.8% Phosphor bronze composition
Sn Content 4.2–5.8% Provides strength and wear resistance
P Content 0.03–0.35% Improves fatigue performance
Density 8.86 g/cm³ Typical value
Electrical Conductivity ~15% IACS Typical annealed condition
Tensile Strength 450–750 MPa Depends on temper
Elongation ≥ 10% Varies by temper
Hardness 80–200 HV Depends on temper
Available Tempers O / H02 / H04 / Spring Temper Custom temper optional
Elongation ≥ 35% Typical annealed/extruded condition
Fabrication Stamping / Forming / Drawing Excellent cold workability
ASTM Standard ASTM B103 / ASTM B139 EN & JIS available

Applications & Use Cases

Proven solutions across diverse industries. From aerospace to marine environments.

Frequently Asked Questions — C51000 Phosphor Bronze

Practical FAQ for engineers and buyers specifying C51000 phosphor bronze (CuSn5 / PB4).

C51000 (often called PB4 or 5% tin phosphor bronze) contains about 4.2–5.8% tin with phosphorus 0.03–0.35% and copper as balance. It is governed by ASTM B103/B103M (plate, sheet, strip, rolled bar), ASTM B139 (rod, bar), and ASTM B505 (continuous cast). EN equivalent is CW451K (CuSn5).
Annealed (O) tensile strength is about 340–410 MPa with elongation 45–55%; in spring temper (H08) it reaches 620–760 MPa with fatigue endurance around 220 MPa. Electrical conductivity is roughly 18–22% IACS and it is non-magnetic. It combines good strength with high elongation, the reason it is used for deep-drawn bellows and springs.
Tin content rises C51000 (5%) → C51900 (6%) → C52100 (8%). Higher tin increases strength, fatigue resistance, and wear resistance but lowers formability and conductivity slightly. C51000 sits in the middle: easier to form than C52100 while stronger than C51100, making it the default general-purpose spring bronze.
Common in spring devices, relay and connector springs, electrical terminals, bearings and bushings, bellows, and wear strips where corrosion resistance and spring-back matter. It solders and brazes well.
Yes. We supply C51000 strip, sheet, rod, and bar to ASTM B103/B139/B505 with MTR/MTC per order and SGS on request. Tempers from annealed to spring hard and custom sizes are available at low MOQ with 10–60 day lead times, plus in-house cutting, CNC, and finishing. Quote requests get a response within 1 business hour.
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