C54400 Free-Machining Phosphor Bronze (B-2)
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Key Engineering Properties
Representative source rows, qualified by their reported conditions. Inspect the tables below for all values, limits, and source notes.
Engineering Summary
UNS C54400 Phosphor Bronze B-2 (88Cu-4Sn-4Pb-4Zn, 0.01-0.50% P) combines the high wear and fatigue endurance of phosphor bronze with 80% machinability rating. Standard alloy for high-precision screw machine sleeve bearings, bushings, thrust washers, and shafts.
C54400 Free-Machining Phosphor Bronze (B-2) Documented Applications
- ›Bearings: Friction & Wear Properties
- ›Bearings: Machining Properties
- ›Bearings: Mechanical Properties
- ›Bushings: Corrosion Resistance
- ›Bushings: Friction & Wear Properties
- ›Bushings: Machining Properties
- ›Bushings: Mechanical Properties
- ›Electrical Connectors: Machining Characteristics
- ›Electrical Connectors: Mechanical Properties
- ›Electrical: Electrical Connectors
- ›Gears: Corrosion Resistance
- ›Gears: Friction & Wear Properties
Recognized Aliases
Source-backed commercial trade name and short designations cataloged in canonical data.
C54400 Free-Machining Phosphor Bronze (B-2) Specifications & Designations
Standard Designations & Applicable Specifications — Semantically classified designations distinguishing primary standard identifiers, commercial trade names, and applicable specification references.
| System | Identifier | Standard System Name | Classification Notes & Provenance |
|---|---|---|---|
| UNSPRIMARY | C54400 | Unified Numbering System | Unified Numbering System standard designation for copper alloys (CDA / SAE / ASTM)Ref: CDA UNS Standard Designations Register (C54400) |
| CDA | Alloy 544 | Copper Development Association Alloy Number | CDA three-digit legacy designationRef: CDA UNS Standard Designations Register (C54400) |
| Recognized Name / Alias | Classification | Technical Usage & Context |
|---|---|---|
| Free-Machining Phosphor Bronze | Standard Commercial Name | CDA Standard Commercial Name |
| Phosphor Bronze B-2 | Commercial Alias | Colloquial or commercial industry synonym |
| C54400 | Commercial Alias | Colloquial or commercial industry synonym |
| Standards Body | Specification Code | Specification Title / Scope | Relationship Type |
|---|---|---|---|
| ASTM | ASTM B139/B139M | PHOSPHOR BRONZE ROD, BAR AND SHAPES | Specification Reference |
| SAE | SAE J463 | WROUGHT COPPER AND COPPER ALLOYS | Specification Reference |
| ASTM | ASTM B103/B103M | PHOSPHOR BRONZE PLATE, SHEET, STRIP AND ROLLED BAR | Specification Reference |
| SAE | SAE J461 | WROUGHT AND CAST COPPER ALLOYS | Specification Reference |
| MILITARY | MILITARY MIL-B-13501 | BEARINGS AND BUSHINGS, BRASS AND BRONZE MACHINED OR FORMED | Specification Reference |
| AMS | AMS 4520 | BRONZE STRIP, COLD ROLLED, HALF HARD | Specification Reference |
C54400 Free-Machining Phosphor Bronze (B-2) Chemical Composition
Chemical Composition (Weight %) — Elemental limits and values from the cited source. Preserves exact semantic limits (minimums, maximums, and ranges).
| Element | Symbol | Atomic No. | Semantic Basis | Specified Value | Unit | Metallurgical Notes & Qualification | Data Status |
|---|---|---|---|---|---|---|---|
| Copper | Cu | 29 | BALANCE | Balance | wt% | Remainder element (Copper).Ref: Copper Development Association (CDA) | VERIFIED |
| Lead | Pb | 82 | RANGE | 3.00 – 4.00 | wt% | CDA chemical composition specification limits for C54400: 3.0 - 4.0 wt%.Ref: Copper Development Association (CDA) | VERIFIED |
| Tin | Sn | 50 | RANGE | 3.50 – 4.50 | wt% | CDA chemical composition specification limits for C54400: 3.5 - 4.5 wt%.Ref: Copper Development Association (CDA) | VERIFIED |
| Zinc | Zn | 30 | RANGE | 1.50 – 4.50 | wt% | CDA chemical composition specification limits for C54400: 1.5 - 4.5 wt%.Ref: Copper Development Association (CDA) | VERIFIED |
| Iron | Fe | 26 | MAXIMUM | ≤ 0.10 | wt% | CDA chemical composition specification limits for C54400: max 0.1 wt%.Ref: Copper Development Association (CDA) | VERIFIED |
| Phosphorus | P | 15 | RANGE | 0.01 – 0.50 | wt% | CDA chemical composition specification limits for C54400: 0.01 - 0.5 wt%.Ref: Copper Development Association (CDA) | VERIFIED |
C54400 Free-Machining Phosphor Bronze (B-2) Physical Properties
Source-specific physical properties. Test temperatures are shown only where reported.
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Density | 8.858 g/cm³ | TYPICAL | Test Temp: 20 °CCDA Physical Properties: Density 0.32 lb/cu in. at 68°F (8.858 g/cm³ at 20°C) | 0.32 lb/cu in. at 68°F | Copper Development Association Inc. | VERIFIED |
C54400 Free-Machining Phosphor Bronze (B-2) Thermal & Thermodynamic Properties
Phase change temperatures, thermal conductivity, specific heat, mean coefficients of thermal expansion across standardized temperature ranges, and recommended thermal processing windows.
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Liquidus Temperature | 998.9 °C | TYPICAL | CDA Physical Properties: Liquidus temperature 1830.0 °F (998.9 °C) | 1830.0 °F | Copper Development Association Inc. | VERIFIED |
| Solidus Temperature | 926.7 °C | TYPICAL | CDA Physical Properties: Solidus temperature 1700.0 °F (926.7 °C) | 1700.0 °F | Copper Development Association Inc. | VERIFIED |
| Thermal Conductivity | 86.54 W/(m·K) | TYPICAL | Test Temp: 20 °CCDA Physical Properties: Thermal conductivity 50.0 Btu/(ft·hr·°F) (86.54 W/(m·K) at 20°C) | 50.0 Btu/ sq ft/ ft hr/ °F at 68°F | Copper Development Association Inc. | VERIFIED |
| Coefficient of Thermal Expansion (CTE) | 17.28 µm/(m·K) | TYPICAL | CDA Physical Properties: CTE 9.6 µin/(in·°F) (17.28 µm/(m·K)) over range 68-57210°F | 9.6 10^-6 per °F | Copper Development Association Inc. | VERIFIED |
| Specific Heat Capacity | 376.8 J/(kg·K) | TYPICAL | Test Temp: 20 °CCDA Physical Properties: Specific heat 0.09 Btu/(lb·°F) (376.8 J/(kg·K)) | 0.09 Btu/ lb /°F at 68°F | Copper Development Association Inc. | VERIFIED |
| Annealing Temperature Range | 482.2 – 676.7 °C | RANGE | CDA Thermal Treatments: Annealing temperature range 900 - 1250°F (482.2 - 676.7°C) | 900 – 1250 °F | Copper Development Association Inc. | VERIFIED |
C54400 Free-Machining Phosphor Bronze (B-2) Electrical Properties
Electrical conductivity and resistivity in their reported units and conditions.
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Electrical Conductivity | 19 % IACS | TYPICAL | Test Temp: 20 °CCDA Physical Properties: Volume conductivity 19.0 % IACS at 68°F (20°C) | 19.0 % IACS at 68°F | Copper Development Association Inc. | VERIFIED |
C54400 Free-Machining Phosphor Bronze (B-2) Mechanical Properties
Contextual Mechanical Properties & Tempers: Engineering strength, ductility, and hardness values grouped by product form, temper, and section thickness. Mechanical properties are contextual and not isotropic averages.
| Product Form | Temper / Condition | Section Size | Tensile (UTS) | Yield Strength | Elongation | Shear Strength | Fatigue Strength | Hardness (Scales Preserved) | Status |
|---|---|---|---|---|---|---|---|---|---|
| Flat Products | 1/2 Hard (H02) · 20 °CSource values and qualifiersTensile Strength: 399.9 MPa (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — Yield Strength (0.5% Ext): 275.8 MPa (TYPICAL)Section Size: 0.04; Section Size: 0.04 in; Yield strength at 0.5% extension under loadCopper Development Association (CDA) — Elongation: 24 % (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — | 0.04 | 399.9 MPa | 275.8 MPa | 24 % | — | — | — | VERIFIED |
| Flat Products | 1/2 Hard (H02)Source values and qualifiersRockwell B Hardness: 68 HRB (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — | 0.04 | — | — | — | — | — | 68 HRB | VERIFIED |
| Flat Products | Hard (H04) · 20 °CSource values and qualifiersTensile Strength: 413.7 MPa (TYPICAL)Section Size: 0.315; Section Size: 0.315 inCopper Development Association (CDA) — Yield Strength (0.5% Ext): 310.3 MPa (TYPICAL)Section Size: 0.315; Section Size: 0.315 in; Yield strength at 0.5% extension under loadCopper Development Association (CDA) — Elongation: 20 % (TYPICAL)Section Size: 0.315; Section Size: 0.315 inCopper Development Association (CDA) — | 0.315 | 413.7 MPa | 310.3 MPa | 20 % | — | — | — | VERIFIED |
| Flat Products | Nominal Grain Size 0.035 mm (OS035) · 20 °CSource values and qualifiersTensile Strength: 303.4 MPa (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — Yield Strength (0.5% Ext): 131 MPa (TYPICAL)Section Size: 0.04; Section Size: 0.04 in; Yield strength at 0.5% extension under loadCopper Development Association (CDA) — Elongation: 50 % (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — | 0.04 | 303.4 MPa | 131 MPa | 50 % | — | — | — | VERIFIED |
| Flat Products | Nominal Grain Size 0.035 mm (OS035)Source values and qualifiersRockwell F Hardness: 65 HRF (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — | 0.04 | — | — | — | — | — | 65 HRF | VERIFIED |
| Flat Products | Spring (H08) · 20 °CSource values and qualifiersTensile Strength: 675.7 MPa (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — Yield Strength (0.5% Ext): 551.6 MPa (TYPICAL)Section Size: 0.04; Section Size: 0.04 in; Yield strength at 0.5% extension under loadCopper Development Association (CDA) — Elongation: 3 % (TYPICAL)Section Size: 0.04; Section Size: 0.04 inCopper Development Association (CDA) — | 0.04 | 675.7 MPa | 551.6 MPa | 3 % | — | — | — | VERIFIED |
| Rod | Hard (H04) · 20 °CSource values and qualifiersTensile Strength: 468.8 MPa (TYPICAL)Section Size: 1; Cold Work: 25%; Section Size: 1 inCopper Development Association (CDA) — Yield Strength (0.5% Ext): 393 MPa (TYPICAL)Section Size: 1; Cold Work: 25%; Section Size: 1 in; Yield strength at 0.5% extension under loadCopper Development Association (CDA) — Elongation: 20 % (TYPICAL)Section Size: 1; Cold Work: 25%; Section Size: 1 inCopper Development Association (CDA) — | 1 | 468.8 MPa | 393 MPa | 20 % | — | — | — | VERIFIED |
| Rod | Hard (H04)Source values and qualifiersRockwell B Hardness: 80 HRB (TYPICAL)Section Size: 1; Cold Work: 25%; Section Size: 1 inCopper Development Association (CDA) — | 1 | — | — | — | — | — | 80 HRB | VERIFIED |
| Rod | Hard (H04) · 20 °CSource values and qualifiersTensile Strength: 517.1 MPa (TYPICAL)Section Size: 0.5; Cold Work: 35%; Section Size: 0.5 inCopper Development Association (CDA) — Yield Strength (0.5% Ext): 434.4 MPa (TYPICAL)Section Size: 0.5; Cold Work: 35%; Section Size: 0.5 in; Yield strength at 0.5% extension under loadCopper Development Association (CDA) — Elongation: 15 % (TYPICAL)Section Size: 0.5; Cold Work: 35%; Section Size: 0.5 inCopper Development Association (CDA) — | 0.5 | 517.1 MPa | 434.4 MPa | 15 % | — | — | — | VERIFIED |
| Rod | Hard (H04)Source values and qualifiersRockwell B Hardness: 83 HRB (TYPICAL)Section Size: 0.5; Cold Work: 35%; Section Size: 0.5 inCopper Development Association (CDA) — | 0.5 | — | — | — | — | — | 83 HRB | VERIFIED |
C54400 Free-Machining Phosphor Bronze (B-2) Processing & Fabrication
Machining, joining, forming, and thermal processing ratings cataloged from the cited authoritative technical reference.
Machinability
Machinability rating: 80% relative to free-cutting brass (C36000 = 100%).
Weldability & Joining
Soldering: Excellent; Brazing: Good; Oxyacetylene Welding: Not Recommended; Gas Shielded Arc Welding: Not Recommended; Coated Metal Arc Welding: Not Recommended; Spot Weld: Not Recommended; Seam Weld: Not Recommended; Butt Weld: Fair
Heat Treatment & Working Ranges
Annealing temperature range: 482.2°C to 676.7°C (900°F - 1250°F).
Forming & Cold Working
Capacity for Being Cold Worked: Good.
Practical Engineering & Fabrication Notes
By Mat Grades Editorial Desk · Updated 2026-11-14. Use alongside the specified product standard and supplier certificate.
Machining & shop-floor behavior
The cataloged machining note for C54400 Free-Machining Phosphor Bronze (B-2) states: Machinability rating: 80% relative to free-cutting brass (C36000 = 100%). A relevant hardness example is Rockwell B Hardness: 68 HRB (typical; 1/2 Hard (H02), H02, Flat Products, 0.04). Use that supplied condition for a trial of the difficult feature. Record tool changes, burr removal, unclamped dimensions and accepted parts per hour. Relative machinability ratings from different reference scales should not be compared as if they were one common test.
Weldability, brazing & joining
The available joining assessment states: Soldering: Excellent; Brazing: Good; Oxyacetylene Welding: Not Recommended; Gas Shielded Arc Welding: Not Recommended; Coated Metal Arc Welding: Not Recommended; Spot Weld: Not Recommended; Seam Weld: Not Recommended; Butt Weld: Fair The first cataloged strength example is Tensile Strength: 399.9 MPa (typical; 1/2 Hard (H02), H02, Flat Products, 0.04; test temperature 20 °C). Assess the final part after joining or thermal processing. Include distortion, cleanup and inspection in the quotation. A material designation or favorable process rating is a starting point for qualification, not evidence that an untested joint meets the drawing.
Corrosion & service environment
Review the working fluid, cleaning agents and dissimilar-metal contacts as separate exposures. The word copper, brass or bronze is too broad to establish compatibility. A process rating does not qualify a pressure boundary, and a thermal-property measurement does not establish a continuous service-temperature limit. The recorded thermal example is Thermal Conductivity: 86.54 W/(m·K) (typical; ; test temperature 20 °C). State the exposure and inspection access in the design record so that a change of installation or cleaning method triggers a review. The selected composition entries are Pb 3–4 wt%, Sn 3.5–4.5 wt%. Chemistry documents identity; it does not establish fluid compatibility.
Selection trade-offs & applications
Use UNS C54400, COMMERCIAL Free-Machining Phosphor Bronze, CDA Alloy 544 to identify the candidate, then specify the product form and delivered condition separately. The catalog lists Bearings: Friction & Wear Properties as an application example. The related candidate C51000 Phosphor Bronze 5% A is linked for comparison; its commonly compared relationship must be checked before substitution. Compare the complete route through machining, joining, finish and inspection. Keep the certificate, required test location and acceptance criteria with the first-article record. A later change of grade, condition or source should be assessed against that same requirement.
Technical references: Copper Development Association (CDA); Copper Development Association (CDA)
C54400 Free-Machining Phosphor Bronze (B-2) Equivalent & Comparable Grades
Comparable Grades & Cross-References: Carefully classified cross-reference relationships for C54400 Free-Machining Phosphor Bronze (B-2). Comparable does not mean equivalent.
| Related Material | Family | Relationship Classification | Metallurgical Notes & Differences | Status | Action |
|---|---|---|---|---|---|
| C51000 Phosphor Bronze 5% A | Copper Alloys | Commonly Compared | C54400 Free-Machining Phosphor Bronze (80% machinability rating) contains lead for screw machine bearings and bushings, whereas C51000 is un-leaded for stamped springs.Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost). | VERIFIED | |
| C36000 Free-Cutting Brass | Copper Alloys | Commonly Compared | C54400 offers bronze bearing properties, wear resistance, and fatigue endurance with 80% machinability, whereas C36000 offers 100% machinability in general brass turning.Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost). | VERIFIED |
Phosphor Bronze Alloy Family
Copper alloys sharing common alloying formulations and metallurgical classifications under the Phosphor Bronze branch.
Sources
Sources & Provenance Trail: Authoritative reference publications, standards specifications, and data registers cited across this material record.
Copper Development Association authoritative technical reference profile for C54400 Free-Machining Phosphor Bronze (B-2).
Unified Numbering System (UNS) designation registration register confirming active C54400 status.