1. Panimula
C93200, kilala rin bilang SAE 660 bearing bronze, is a widely used copper-based alloy specifically formulated for applications requiring excellent wear resistance and machinability.
Classified under lead-tin bronze alloys, it has become an industry standard in bearings and bushings due to its well-balanced mechanical properties and cost-effective performance.
In industrial metallurgy, C93200 plays a critical role in components operating under moderate loads and speeds.
Its versatility across manufacturing environments—especially in fluid power, marine, and mechanical systems—makes it a mainstay in both original equipment manufacturing (OEM) and aftermarket part replacement.
2. What is C93200 Copper Alloy?
C93200, kilala rin bilang SAE 660 bearing tanso, Ito ay isang mataas na pagganap leaded tin bronze alloy widely used for applications involving friction, magsuot ng, and moderate loads.
It is engineered for superior machinability, embedded debris tolerance, and good corrosion resistance, particularly in lubricated environments.
As a standard in the bronze family, it is recognized for its balance of mekanikal na lakas, tribological performance, at kahusayan sa gastos.
C93200 is most commonly produced via casting processes such as sand, centrifugal, and permanent mold casting, and is widely used in bushings, thrust washers, mga bearing, at mga bahagi ng pump.
Its composition and microstructure make it especially effective for components operating in boundary or mixed lubrication regimes.
Komposisyon ng kemikal
| Elemento | Karaniwang Saklaw (%) | Function in Alloy |
| Tanso (Cu) | 83.0 – 88.5 | Base metal; provides ductility and conductivity |
| Tin (Sn) | 6.3 – 7.5 | Adds strength, tigas na tigas, at magsuot ng resistensya |
| Humantong sa (Pb) | 6.0 – 8.0 | Enhances machinability and embeddability |
| Sink (Zn) | 1.0 – 4.0 | Nagpapabuti ng pagkalikido; minor strength contributor |
| Bakal na Bakal (Fe) | ≤ 0.25 | Impurity control; excessive iron may cause brittleness |
| Nikel (Ni) | ≤ 0.25 | Opsyonal na; improves corrosion resistance |
| Others | ≤ 0.50 (kabuuang) | Limited trace elements |
Standards and Designations
- UNS Number: C93200
- SAE Designation: SAE 660
- Common Trade Names: Pagdadala ng Bronze, 660 tanso, SAE 660 tanso
- ASTM Specifications: B505 (continuous cast), B271 (centrifugal cast), B148 (ingot)
- ISO: CuSn7Pb7Zn4
3. Mechanical Properties of C93200 Copper Alloy
C93200 (SAE 660) copper alloy is renowned for its well-balanced mechanical properties that make it ideal for bearing and bushing applications under moderate loads and speeds.
The alloy’s performance is a function of its composition, mikroistruktura, and casting method.
It exhibits mahusay na machinability, good fatigue strength, at outstanding wear behavior—especially in lubricated environments.
Key Mechanical Properties
| Pag-aari | Tipikal na Halaga | Mga Tala |
| Lakas ng Paghatak | 220 – 275 MPa | Varies with casting method (buhangin kumpara. centrifugal) |
| Yield Lakas (0.2% Offset) | 105 – 130 MPa | Higher in centrifugal cast components due to finer grain structure |
| Pagpapahaba sa Break | 10 – 20% | Indicates moderate ductility |
| Brinell tigas na tigas | 65 – 85 HB | Can increase after work hardening or surface treatment |
| Compressive Yield Strength | ~120 MPa | Relevant for bearing surface loads |
| Lakas ng Paggupit | ~170 MPa | Important in rotating contact applications |
| Lakas ng Pagkapagod | ~90 MPa (at 10⁷ cycles) | Based on rotating beam tests in lubricated conditions |
| Modulus ng Pagkalastiko | ~100 GPa | Governs elastic deformation under stress |
Machinability
C93200 exhibits mahusay na machinability, often rated at 80–90% compared to free-cutting brass (C36000 = 100%).
The presence of lead (6–8%) contributes significantly to chip control, reduced tool wear, and high surface finish quality.
This makes C93200 a preferred choice in CNC-machined bearing shells and hydraulic bushings.
- Machinability Rating: ~85%
- Tool Material Compatibility: HSS and carbide tools
- Typical Surface Finish: 0.8 – 1.6 µm Ra with appropriate feed rates
4. Physical Properties of C93200 Copper Alloy
C93200, or SAE 660 bearing bronze, exhibits a well-balanced set of pisikal na katangian that make it highly suitable for applications involving sliding motion, thermal cycling, and moderate mechanical stress.
These physical characteristics contribute directly to the alloy’s effectiveness in bearings, mga bushing, and hydraulic components—especially where thermal katatagan, dimensional integrity, at kondaktibiti ay kinakailangan.
Key Physical Properties
| Pag-aari | Tipikal na Halaga | Remarks |
| Densidad ng katawan | 8.8 g/cm³ (8800 kg/m2) | Provides mass and stability in rotating equipment |
| Saklaw ng Pagtunaw | 930 – 1020 °C | Slightly lower than pure copper due to lead and tin |
| Thermal kondaktibiti | ~58–70 W/m·K | Lower than pure copper but sufficient for heat dissipation |
| Tiyak na Kapasidad ng Init | ~0.38 J/g·K | Affects thermal response in rapidly cycling applications |
| Koepisyent ng Thermal Expansion | ~18.5 × 10⁻⁶ /K | Important in press-fit and high-temperature assemblies |
| Electrical kondaktibiti | ~10–15% IACS | Not typically used in electrical circuits |
| Modulus ng Pagkalastiko | ~100 GPa | Indicates stiffness under load |
| Thermal Diffusivity | ~2.4 × 10⁻⁵ m²/s | Reflects the rate of heat spread in the material |
| Ratio ng Poisson | ~0.31 | Defines lateral expansion under uniaxial stress |
Pagganap ng Thermal
C93200 maintains structural integrity over a broad operating temperature range, karaniwan hanggang sa 205°C (400°F) in continuous service, making it suitable for thermally stressed components.
Katatagan ng Dimensyon
The alloy exhibits mababang pag-urong Sa panahon ng paglamig (~1.2–1.5%) and a uniform microstructure when properly cast.
5. Casting Characteristics of C93200 Copper Alloy
C93200 copper alloy, commonly known as SAE 660 bearing bronze, is highly regarded in foundry practice for its mahusay na castability, dimensional na pagkakapare-pareho, at adaptability to various casting methods.
Its unique composition—particularly the presence of lead (Pb), tin (Sn), at sink (Zn)—makes it especially favorable for casting complex shapes while maintaining good surface finish and internal soundness.
Key Casting Characteristics
| Casting Property | C93200 Copper Alloy | Remarks |
| Pagkatubig | Mataas na | Lead and tin improve molten metal flow into intricate molds |
| Shrinkage Rate | ~1.2 – 1.5% | Allows accurate pattern compensation |
| Hot Shortness | Mababa ang | Good resistance to cracking during solidification |
| Porosity Tendency | Katamtaman | Controlled through gating and degassing |
| Gas Absorption | Katamtaman | Requires proper venting and melt treatment |
| Machinability After Casting | Napakahusay | As-cast microstructure aids cutting and finishing |
| Soundness | Mataas na (in centrifugal and continuous cast) | Superior structural integrity in critical components |
Common Casting Methods for C93200
| Paraan ng Paghahagis | Suitability for C93200 | Mga Karaniwang Aplikasyon |
| buhangin paghahagis | Excellent for large and complex shapes | Mga pabahay ng bomba, Mga blangko ng gear, large bushings |
| Centrifugal Casting | Ideal for cylindrical parts; minimal na porosity | High-precision bushings, sleeve bearings, Mga liner |
| mamatay paghahagis | Hindi gaanong karaniwan (lead content can degrade dies) | Maliit na, high-volume components if alloy modified |
| Permanenteng amag paghahagis | Good for repeatability and finer grain | Medium-sized parts requiring better surface finish |
| Patuloy na Paghahagis | Preferred for stock shapes (mga baras, mga tubo) | Machined bearings, bar stock for custom fabrication |
6. Wear Resistance and Tribological Performance
C93200’s tribological superiority stems from its unique microstructure:
- Self-Lubrication: Dispersed lead particles (5–20 μm in diameter) act as “micro-bearings”, smearing across sliding surfaces to form a low-friction film.
This reduces the coefficient of friction to 0.15–0.20 (mga bes. 0.6–0.8 for steel-on-steel). - PV Limit: Safe for continuous operation at PV (pressure × velocity) values up to 1.5 MPa·m/s (hal., electric motor bearings).
Exceeding this threshold causes lead melting (lead melts at 327°C), accelerating wear. - Wear Mechanism: Exhibits mild adhesive wear, with minimal debris generation—critical for clean environments like food processing (with strict lead leaching controls).
In field tests, C93200 bushings in agricultural machinery lasted 10,000+ hours under intermittent lubrication, outperforming brass (C36000) by 3× and cast iron by 2×.
7. Corrosion Resistance of C93200 Copper Alloy
C93200 offers moderate corrosion resistance in non-aggressive environments:
- Atmospheric Exposure: Forms a protective patina (basic copper carbonate) in rural and urban environments, with corrosion rates <0.01 mm/year—suitable for outdoor machinery.
- Freshwater: Resists corrosion in pH 6–8 water (hal., cooling systems, freshwater pumps) with rates <0.02 mm / taon.
- Saltwater/Chlorides: Poor resistance—corrosion rates exceed 0.1 mm/year in seawater (35,000 ppm Cl⁻) due to lead’s susceptibility to pitting and tin’s limited ability to form a protective oxide layer.
- Chemicals: Tolerates dilute oils, Mga Grasa, and mild alkalis (hal., 10% NaOH at 25°C) but corrodes rapidly in acids (hal., 5% Sulpuriko acid: 1.2 mm / taon).
Protection Strategies: Epoxy coatings, tin plating, or chromate conversion coatings extend service life in humid or coastal environments by 2–3×.
8. Applications of C93200 Copper Alloy
C93200’s versatility spans industries requiring reliable sliding components:
- Mga bearing & Mga Bushing: Automotive crankshaft bearings (meeting SAE 660 mga pagtutukoy), industrial gearbox bushings, and electric motor bearings—leveraging self-lubrication to reduce maintenance.
- Hydraulic Components: Mga stems ng balbula, pump impeller sleeves, and cylinder liners—resisting wear from hydraulic fluids (hal., mineral oil, water-glycol mixtures).
- Automotive: Transmission synchronizer rings, steering linkage bushings, and suspension pivot points—withstanding 100,000+ km of service in passenger vehicles.
- Marine (Freshwater): Inland boat propeller shafts, mga bahagi ng pump, and hatch hinges—avoiding seawater exposure.
- Pangkalahatang Pang-industriya: Conveyor rollers, press tool guides, and agricultural machinery pivot points—tolerating dirt, alikabok na, and intermittent lubrication.
9. Advantages of C93200 Copper Alloy
- Self-Lubrication: Lead particles eliminate the need for continuous lubrication in low-maintenance applications, reducing downtime and operational costs.
- Exceptional Machinability: 80–90% machinability rating (mga bes. 30% for C95400 aluminum bronze) cuts production time by 20–30% and extends tool life.
- Ductility: 15–20% elongation absorbs shock loads, reducing failure risk in heavy machinery (hal., construction equipment).
- Pagiging Epektibo sa Gastos: 30–40% cheaper than aluminum bronze (C95400) for equivalent low-load performance, Ginagawa itong perpekto para sa mataas na dami ng produksyon.
- Katatagan: Adapts to diverse casting methods, enabling complex geometries without secondary machining—reducing part count and assembly costs.
10. Limitations of C93200 Copper Alloy
- Lead Toxicity: Restricted in food contact (FDA 21 CFR 178.3280 limits lead to <0.1%) at mga aparatong medikal, requiring lead-free alternatives (hal., C86300 manganese bronze) in these sectors.
- Sensitivity ng Temperatura: Loses 20% of tensile strength at 150°C; unsuitable for high-heat applications (hal., engine exhaust components, industrial ovens).
- Low Hardness: 60–80 HB limits use in high-load (≥5 MPa) or high-speed (≥5 m/s) mga aplikasyon, where aluminum bronzes or steels are preferred.
- Corrosion Vulnerability: Not recommended for seawater, acidic na kapaligiran, or high-chloride solutions (hal., road salt exposure).
11. Comparative Analysis with Other Bronzes
C93200 (SAE 660) bearing bronze is one of the most widely used copper alloys due to its excellent balance of machinability, Paglaban sa Pagsusuot, at katatagan.
Gayunpaman, in demanding applications, it is often compared to other bronze alloys such as C95400 (aluminum bronze), C83600 (red brass), at C36000 (malayang pagputol ng tanso).
Talahanayan ng Paghahambing: C93200 vs. Other Bronze Alloys
| Pag-aari / haluang metal | C93200 (SAE 660) | C95400 (Aluminyo Bronze) | C83600 (Pulang tanso) | C36000 (Brass na may libreng pagputol) |
| Komposisyon | Cu-Sn-Pb-Zn | Cu-Al-Fe-Ni | Cu-Sn-Zn-Pb | Cu-Zn-Pb |
| Lakas ng Paghatak (MPa) | 200–275 | 450–700 | 170–250 | 345–550 |
| Ang katigasan ng ulo (Brinell) | 60–80 | 125–175 | 50–70 | 80–100 |
| Machinability | Napakahusay (80–90%) | Katamtaman (30–40%) | Mabuti na lang (60%) | Napakahusay (90%+) |
| Paglaban sa kaagnasan | Katamtaman | Napakahusay (esp. tubig dagat) | Mabuti na lang | Poor to moderate |
| Magsuot ng Paglaban | Mabuti na lang | Napakataas na | Makatarungan | Katamtaman |
| Gastos | Katamtaman | Mataas na | Katamtaman | Mababa ang |
| Friction Applications | Best with lubrication | Excellent dry or lubricated | Not ideal | Limitado |
| Casting Suitability | Napakahusay | Fair to Good | Napakahusay | Not typically cast |
| Typical Uses | Mga bearing, mga bushing | High-load bushings, mga bomba | Pagtutubero, Mga balbula | Mga tornilyo, mga angkop na bagay |
C93200 vs. C95400 (Aluminyo Bronze)
- Lakas ng loob & Load Capacity: C95400 significantly outperforms C93200 in tensile strength and wear resistance, ginagawang mas angkop para sa mataas na load, high-speed applications like gear components and industrial valves.
- Paglaban sa kaagnasan: C95400 exhibits exceptional resistance to seawater, Mga klorido, at mga kemikal, making it the preferred material in marine and offshore Mga kapaligiran.
- Machinability: While durable, C95400 is harder to machine and more expensive to produce than C93200.
- Kaso ng Paggamit: Pumili C93200 for general-purpose bearings; choose C95400 when strength and corrosion resistance are critical.
C83600 (Pulang tanso) mga bes. C93200
- Gastos & Katatagan: Both alloys are cast-friendly, pero C83600 is cheaper and often used in non-critical applications like plumbing and decorative parts.
- Pagganap: C93200 has better wear resistance and pressure-handling capacity, lalo na para sa sliding or rotating components.
- Kaso ng Paggamit: Pumili C83600 for low-load, corrosion-resistant fittings; gamitin ang C93200 for moving parts requiring lubrication and dimensional stability.
C93200 vs. C36000 (Brass na may libreng pagputol)
- Machinability: C36000 has the highest machinability rating among copper alloys (>90%), ideal for high-speed turning and precision components.
- Mga Katangian ng Mekanikal: While strong and precise, C36000 lacks the tribological and fatigue properties required for bearing surfaces.
- Kaso ng Paggamit: Gamitin ang C36000 for fittings, mga konektor, and light-duty components; gamitin ang C93200 saan banda lubrication, Paglaban sa Pagsusuot, at katatagan are key.
12. Pangwakas na Salita
C93200 copper alloy remains a cornerstone of industrial design for bearing-grade applications due to its combination of machinability, tribological stability, at paglaban sa kaagnasan.
While it may not suit all high-load environments, it offers dependable, cost-effective performance in countless machinery types—particularly when moderate loads, good lubrication, and tight tolerances are essential.
Mga FAQ
Can C93200 be used without lubrication?
Oo nga, in low-load (≤1 MPa) and low-speed (≤1 m/s) mga aplikasyon. Its lead particles act as internal lubricants, reducing friction.
Gayunpaman, periodic lubrication extends service life in higher PV (pressure × velocity) scenarios.
Is C93200 suitable for seawater exposure?
Hindi. Seawater’s high chloride content causes pitting corrosion in C93200, with rates exceeding 0.1 mm / taon. For marine applications, use C95400 aluminum bronze, which resists seawater corrosion.
What are alternatives to C93200 for high-load applications?
For high-load (≥5 MPa) or high-speed (≥5 m/s) mga aplikasyon, C95400 aluminum bronze is preferred, as it offers 2× the tensile strength (450–550 MPa) and superior wear resistance.
Can C93200 be welded or brazed?
Welding is not recommended, as lead vaporizes at welding temperatures (≥327°C), causing porosity and brittleness.
Brazing (with silver-based fillers) is possible but requires careful surface preparation to avoid lead contamination of the joint. Mechanical fastening (bolting, press-fitting) is preferred for assembly.
