51000 Phosphor Bronze Sheet is lead‑free CuSn5 copper‑tin‑phosphorus wrought alloy, widely used for electrical springs, connectors, marine fittings and precision stamped components.
Quick Grade‑Selection Answer For Your Project: Pick C51000 for lead‑free, high‑fatigue electrical springs, general marine hardware and stamping parts; choose C52100 when higher tin content is needed for enhanced wear & corrosion resistance; select C54400 leaded phosphor bronze mainly for high‑volume CNC‑machined bushings where excellent machinability is priority.
Many buyers face material‑related failures caused by wrong grade pick, unstable mechanical property or inconsistent sheet flatness. As your reliable China factory supplier, HSMetal provides full‑range phosphor bronze sheets including C51000, C52100 and C54400. We guarantee stable delivery and mill test certificate available for every shipment. Custom cut‑to‑size service supports both R&D sampling and large‑volume serial production. For chemical compatibility reference under corrosive working conditions, visit Read our phosphor bronze chemical‑resistance blog.
Related Standards
What is C51000 Phosphor Bronze Sheet
UNS C51000 (CuSn5) phosphor bronze sheet is composed of copper, 4.2‑5.8% tin plus trace phosphorus as de‑oxidizer, lead‑free per standard specification.
It balances good electrical conductivity, outstanding fatigue resistance, moderate corrosion resistance and excellent cold formability. It can be supplied in multiple tempers including annealed O, 1/4H, 1/2H, H and EH to satisfy stamping, bending and spring‑function requirements. The material performs well in soldering and brazing, and accepts nickel or silver plating for electronic component surface finishing.
Chemical Composition
Typical Composition Range of C51000 Phosphor Bronze:
- Copper (Cu): Balance (approximately 94%–96%)
- Tin (Sn): 4.2%–5.8% – the primary strengthening element, which enhances hardness and corrosion resistance.
- Phosphorus (P): 0.03%–0.35% – acts as a deoxidiser, refines the grain structure, and improves machinability.
- Impurity control: Lead (Pb), iron (Fe), and other trace elements are strictly limited to very low levels (typically < 0.1%) to ensure high material purity.
The combined effect of tin and phosphorus gives the alloy excellent elasticity and resistance to stress relaxation, while still preserving the inherent electrical conductivity of the copper matrix.
Key Properties
| Property | Value |
|---|---|
| Density | 8.86 g/cm³ |
| Electrical Conductivity | 15–20% IACS |
| Thermal Conductivity | 69–75 W/m·K |
| Modulus of Elasticity | 110–117 GPa |
| Melting Range | 975–1060°C |
| UTS (Spring Temper) | 620–760 MPa |
| Fatigue Endurance Limit | ~220 MPa |
Why C51000 - Performance Advantages
1. Superior Cold Formability
C51000 offers the best cold working characteristics among standard phosphor bronze grades. It can be deep drawn into bellows, stamped into complex connector geometries, and bent to tight radii without cracking.
2. Reliable Fatigue Performance
With a fatigue endurance limit of approximately 220 MPa in spring temper, C51000 sustains 50,000–100,000+ spring deflection cycles in connector applications - ideal for SIM card trays, USB spring contacts, and PCB edge connectors.
3. Proven Corrosion Resistance
C51000 performs well in humid environments, industrial atmospheres, and mild chemical exposure. It is suitable for marine hardware and chemical processing components where intermittent exposure occurs.
4. Excellent Solderability & Plating
The alloy solders and brazes exceptionally well, and accepts tin, nickel, and gold plating without adhesion issues - critical for connector manufacturing.
Phosphor Bronze Grade Comparison & Application‑Based Selection Guide
Different phosphor bronze grades are engineered for distinct working conditions. Select alloy according to your core requirement among spring property, corrosion resistance, machinability and RoHS compliance.
| Alloy Grade | Key Composition | Core Strength | Typical Application Scenarios |
|---|---|---|---|
| C51000 | CuSn5, lead‑free | Superior fatigue & spring performance, good corrosion resistance | Electrical connectors, relay springs, instrument diaphragms, marine fittings, stamped contact parts |
| C52100 | CuSn8, lead‑free | Higher tin for improved wear and corrosion resistance | Heavy‑duty springs, marine hardware, high‑wear mechanical components |
| C54400 | CuSn‑Pb‑Zn, lead‑containing | Excellent free‑cutting machinability | CNC bushings, thrust washers, high‑volume machined parts; not ideal for strict lead‑free RoHS projects |
Important note: C54400 contains lead, so please confirm RoHS requirement before ordering.
Selection Rule of Thumb:
- C51000 - When formability and cost matter most
- C51900 - When you need 10–15% more strength without sacrificing much formability
- C52100 - When maximum fatigue resistance and corrosion resistance are required
Available Specifications & Custom Service
Standard dimension range
Thickness: 0.2 mm‑12 mm
Width: up to 1200 mm
Length: custom‑cut according to drawing
Our custom capabilities
Custom cut‑to‑size sheets, blanks for prototype and mass production
Different tempers customized to your stamping / spring design
Surface options: mill finish, brushing, polishing
Small‑batch sample order support; large‑volume serial production capacity
Besides sheets, we also supply matching phosphor bronze strip, bar and wire for one‑stop material sourcing.
Core Product Features of HSMetal C51000 Phosphor Bronze Sheet
- Lead‑free CuSn5 composition complying with ASTM B103/B103M standard
- Multiple tempers available: O, 1/4H, 1/2H, H, EH to match stamping or spring function
- Stable flatness and tight thickness tolerance for progressive stamping production
- Good fatigue resistance for repeated flexing spring components
- Decent corrosion performance for atmospheric and mild marine environments
- Good solderability & brazing performance, compatible with Ni / Ag surface plating
- Full batch inspection on chemical composition, hardness and mechanical properties
Application Scenarios
| Industry | Applications | Recommended Temper |
|---|---|---|
| Electronics | Connectors, terminals, relay springs, PCB contacts | H04–H08 |
| Automotive | Bushings, bearings, clutch components, electrical contacts | H04 |
| Industrial | Bellows, diaphragms, fasteners, lock washers | O–H04 |
| Marine | Corrosion-resistant fittings, valve components | H04–H08 |
| Architectural | Decorative sheet, name plates | O (annealed) |
Commercial and Delivery terms
| Item | Details |
|---|---|
| Minimum Order Quantity | Support both R&D sample orders and mass‑volume production orders.Small custom cut‑to‑size samples are available for lab evaluation.Mass‑production MOQ depends on dimension & temper, please confirm with sales. |
| Price & Quotation | Quotation is calculated according to grade, dimension, temper, quantity and processing requirements.Price excludes freight, insurance and import duties.Quotation validity: 30 days. Subject to raw‑material market fluctuation. |
| Mill Test Certificate | Available for every shipment, covering chemical composition, mechanical properties and hardness data.Third‑party inspection can be arranged at buyer's cost upon request. |
| Custom Cut‑to‑Size Service | Custom cut‑to‑size processing for C51000 phosphor bronze sheet.General tolerance follows industrial standard. Special tight tolerance needs to be clarified during inquiry.Extra processing cost may apply for non‑standard blanks. |
| Lead‑time | Standard stock items: 7‑14 working days.Non‑standard temper / special thickness / custom cutting: 15‑30 working days.Exact lead‑time confirmed on formal proforma invoice. |
| Shipping & Packaging | Seaworthy export‑grade packaging to prevent scratch, deformation and oxidation.Shipping options: sea freight, air freight, express courier for small samples.Freight cost is on buyer's account unless special agreement. |
| Payment Terms | Main term: T/T (Telegraphic Transfer). 30% deposit after PI confirmation, balance before shipment.Other payment terms are negotiable. |
| Acceptance & Claim | Buyer shall inspect quantity, dimension and surface within 15 working days after goods arrival.Quality claim requires valid inspection evidence.Claims from improper post‑processing, storage or transit will not be accepted. |
| After‑sales Technical Support | Free technical consultation: grade selection, temper recommendation and material processing tips, available after order completion. |
About Us
As a specialized China factory supplier for phosphor bronze alloys, HSMetal runs complete in‑house workflow including melting, hot rolling, precision cold rolling, temper annealing and custom cutting for C51000, C52100 and C54400 phosphor bronze sheets. We follow ASTM B103/B103M industry standards and strictly control chemical composition tolerance. Every production batch goes through full‑range lab testing and comes with complete mill test certificates. Beyond supplying standard and custom‑cut sheets for prototype and mass‑production projects, our material engineering team provides practical technical support including grade selection advice, temper suggestion and stamping‑process tips. We help global customers avoid common material‑caused risks such as wrong‑grade selection, improper temper choice and unstable mechanical performance, acting as your reliable one‑stop partner for phosphor‑bronze alloy solutions.
Our Factory
Vacuum Melting Furnace
Hot Rolling Mill For High Performance Alloy Plate Production Equipment
Aging Treatment Equipment
4-Tensile Testing Machine
Flaw Detector
Hardness Tester
FAQ
Q1: Should I choose C51000, C52100 or C54400 for my project?
A: Use our quick grade‑selection table above. C51000 is the general‑purpose lead‑free option for springs and connectors. Pick C52100 for better wear‑corrosion performance. Choose C54400 only if high‑speed CNC machining is your top priority and lead‑containing material is acceptable. You may send us your working condition and drawing for free grade recommendation.
Q2: What temper should I select for stamping spring contacts?
A: Annealed O or 1/4H for heavy forming / deep drawing; 1/2H or H temper for finished spring contacts which need stable contact force after stamping.
Q3: Is mill test certificate provided with shipment?
A: Yes. Each shipment is accompanied with mill test certificate covering chemical analysis, hardness and mechanical test data. Third‑party inspection can be arranged upon request.
Q4: Do you accept small R&D sample orders of C51000 phosphor bronze sheet?
A: Yes. Custom cut sample sheets and mass‑volume bulk orders are both supported.
Q5: What's the difference between C51000 and C51900 phosphor bronze sheet?
A: C51900 has slightly higher tin content (5.5–7.0% vs 4.2–5.8%), giving it higher strength and fatigue resistance at a small cost to formability and conductivity.
Q6: Can C51000 sheet be used in seawater?
A: C51000 offers good corrosion resistance but is not the optimal choice for continuous immersion. For marine applications, C52100 (8% tin) provides superior saltwater resistance.
Q7: What thickness tolerance can you achieve?
A: Standard tolerance is ±0.15mm. Precision tolerance of ±0.05mm is available for critical applications.
Q8: Do you provide samples?
A: Yes - free samples for standard sizes. Custom specifications may require sample charges.Need customer pay for shipping cost
Q9: What certifications do you provide?
A: Mill Test Certificate (MTC), ASTM B103 compliance, and third-party inspection on request.
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