1. Įvadas
C93200 leaded tin bronze occupies a special position in engineering practice because it solves a problem that appears in countless machines: how to make a bearing material that is strong enough, slippery enough, machinable enough, and economical enough to be used at scale.
It is not the hardest bronze, nor the strongest, nor the most corrosion-resistant in the entire copper-alloy family. Its importance lies elsewhere.
C93200 is a highly balanced bearing bronze whose combination of antifriction behavior, Aparatas, slėgio sandarumas, and service reliability has made it one of the most widely specified bearing materials in industrial equipment.
2. What Is C93200 Leaded Tin Bronze?
C93200 is a high-leaded tin bronza designed primarily for guolis, bushing, and general wear-service applications.
It is widely recognized as SAE 660, a designation that reflects its long-standing role as a standard bearing bronze in industrial machinery.
Praktine inžinerine prasme, C93200 is valued because it combines good antifriction behavior, adequate strength, puikus apdirbamumas, and dependable corrosion resistance in one cast copper alloy.
Unlike structural bronzes that are selected mainly for maximum load capacity, C93200 is selected for balanced tribological performance.
That means it is built to work in real contact conditions: rotating shafts, slydimo paviršiai, moderate loads, and lubrication regimes that are often less than ideal.
This is why it has become one of the most widely used bronze grades for bearings and bushings across pumps, staklės, variklius, and general mechanical equipment.
Savybės
Good antifriction performance
C93200 is engineered for sliding contact. Its lead content helps reduce friction and improve conformability, while the tin-bronze matrix provides the strength needed for bearing service.
That combination is the reason it is so often described as a general-purpose bearing bronze.
Puikus apdirbamumas
One of C93200’s major advantages is that it machines very well for a bearing bronze.
Published data assign it a machinability rating of 70, which makes it practical for producing accurate bores, faces, and bearing geometries after casting.
Adequate strength and hardness for medium-duty service
C93200 is not a high-strength bronze in the structural sense, but it offers enough tensile strength, derliaus stiprumas,
and hardness for medium loads and medium speeds, which are the most common bearing-service conditions.
Geras atsparumas korozijai
The alloy is widely used in pumps, valve-related components, and machinery exposed to industrial or mildly corrosive environments because it offers reasonable corrosion resistance along with wear resistance.
It is also noted as not being subject to dezincification.
Broad casting practicality
C93200 is available in several established casting routes, įskaitant Išcentrinis, tęstinis, Nuolatinis pelėsis, and sand casting, which makes it adaptable to both stock production and finished parts.
Equivalent Designations to UNS C93200
| Standartas / sistema | Equivalent designation |
| SAE | SAE 660, SAE J461, SAE J462 |
| ASTM | ASTM B271, ASTM B30, ASTM B505, ASTM B584, ASTM B763 |
| QQ-C-390 |
3. Chemical Composition of C93200 Leaded Tin Bronze
The precise chemical composition of C93200 is meticulously controlled to achieve its desired properties.
The typical composition, as per ASTM B505 for continuous cast material, is presented in the table below
| Elementas | Composition range (%) |
| Cu | 81.0–85.0 |
| Pb | 6.0–8.0 |
| Sn | 6.3–7.5 |
| Zn | 2.0–4.0 |
| Į | iki 1.0 |
| Sb | iki 0.35 |
| Fe | iki 0.20 |
| P | iki 0.15 |
| S | iki 0.08 |
| Ir | iki 0.005 |
| Al | iki 0.005 |
4. Physical and Mechanical Properties of C93200
Fizinės savybės
The values below are representative continuous-cast values at room temperature.
| Nuosavybė | US Customary | Metrika |
| Melting point – liquidus | 1790 ° F. | 977 ° C. |
| Melting point – solidus | 1570 ° F. | 854 ° C. |
| Tankis | 0.322 lb/in³ | 8.91 g/cm³ |
| Specific gravity | 8.91 | 8.91 |
| Elektros laidumas | 12% IACS | 0.07 MS/m |
| Šilumos laidumas | 33.6 Btu/ft²·hr·°F | 58.2 W/m · k |
| Šiluminio plėtimosi koeficientas | 10 × 10⁻⁶ /°F | 17.3 × 10⁻⁶ /°C |
| Specific heat capacity | 0.09 Btu/lb·°F | 377.1 J/kg · k |
| Tamprumo modulis | 14,500 ksi | apie 100 GPA |
Mechaninės savybės
| Nuosavybė | US Customary | Metrika |
| Tempimo stiprumas, min. | 35 ksi | 241 MPA |
| Yield strength at 0.5% extension, min. | 20 ksi | 138 MPA |
| Elongation in 2 į. / 50 mm, min. | 10% | 10% |
| Brinelio kietumas, tipiškas | 65 BHN | 65 BHN |
| Apdirbamumo įvertinimas | 70 | 70 |
| Izod impact | 5.9 ft·lbf | 8 J |
| Compressive strength | 45,700 psi | 315 MPA |
| Nuovargio stiprumas | 16,000 psi | 110 MPA |
| Puasono koeficientas | 0.34 | 0.34 |
5. Corrosion Resistance of C93200
General corrosion behavior
C93200 is generally regarded as a corrosion-resistant bearing bronze rather than a corrosion-specialty alloy.
Published material notes describe it as having reasonable corrosion resistance and note that it is suitable for use in numerous environments ir many industrial chemicals.
It is also repeatedly identified as not subject to dezincification, which is an important practical advantage for copper-zinc-containing service environments.
Performance in seawater, sūrymas, and wet service
One of the most important practical strengths of C93200 is its behavior in seawater and brine.
Multiple published references state that the alloy has reasonable corrosion resistance to seawater and brine,
which is why it is commonly used for siurblio komponentai, vožtuvo komponentai, siurblio sparnuotės, ir įvorės exposed to moist or moderately saline environments.
Corrosion resistance in industrial machinery
C93200 is also used in staklės, general-utility bearings, hydraulic press components, atraminės poveržlės, and automotive fittings, and those application lists repeatedly emphasize corrosion resistance to numerous environments ir many industrial chemicals.
That indicates the alloy is not limited to simple wet service; it is also well suited to the mixed thermal, tepimas, and atmospheric exposures found in industrial machinery.
The practical implication is that C93200 has a useful balance of atsparumas korozijai + antifriction behavior + Aparatas.
For machine builders, that combination matters because a bearing alloy must survive not only motion and load but also the real-world contaminants, alyvos, aušinimo skysčiai, and ambient moisture that accompany industrial operation.
C93200’s corrosion profile is therefore part of its broader tribological value, not a standalone feature.
6. Processing and Manufacturing
Liejimas
C93200 is fundamentally a casting bronze, and one of its practical strengths is that it can be produced by several established casting routes, įskaitant nuolatinis liejimas, centrifugal casting, Smėlio liejimas, ir nuolatinis liejimas į formą.
That versatility makes it useful for both stock production and near-net-shape parts, especially in bearing, bushing, and general machine-component supply chains.
Published alloy data also show that C93200 has a high casting yield, medium fluidity, medium gassing tendency, ir low shrinkage in solidification,
which is a favorable combination for producing sound castings with relatively manageable process losses.
Tai pasakė, “favorable” does not mean “forgiving.” Like most bearing bronzes, C93200 still rewards disciplined melt handling, stable pouring practice, and good gating and feeding design.
Its production value comes from the fact that it can be cast reliably into practical engineering shapes while still delivering the antifriction and machinability characteristics that make it useful in service.
Apdirbimas
Among bearing bronzes, C93200 is widely appreciated for its machining behavior.
Its published machinability rating is 70, which places it well above many structural bronzes and makes it highly practical for secondary machining after casting.
This matters because bearing components often require accurate bores, faces, grioveliai, and fitted surfaces, and an alloy that machines cleanly reduces tooling burden, ciklo laikas, ir gamybos savikaina.
The machining advantage is not accidental. C93200 is a švino alavo bronza, and lead contributes to chip-breaking and lubricity during cutting.
That is why this alloy can be cast into a near-net form and then finish-machined without becoming a production bottleneck.
Prisijungimas: Best Suited to Soldering and Brazing
C93200 is much more compatible with soldering and brazing than with conventional welding.
Published fabrication data rate soldering as excellent ir brazing as good, kol oxyacetylene welding, gas-shielded arc welding, and coated metal arc welding are not recommended for this alloy.
That pattern is consistent with the alloy’s intended role as a cast-and-machine bearing bronze rather than a weld-centric structural material.
Terminis apdorojimas
C93200 does ne respond to conventional strengthening heat treatment.
The published data indicate a stress-relieving temperature of 500°F / 260° C., but the alloy does not gain significant hardening response from quench-and-temper or precipitation-hardening cycles.
That is an important distinction: heat treatment is used here mainly to relieve residual stress, not to transform the alloy into a higher-strength material class.
7. Advantages and Limitations of C93200 Bronze
Privalumai
- good antifriction behavior
- geras apdirbamumas
- adequate strength and hardness for bearing service
- pressure-tight characteristics
- broad availability and familiar processing behavior
- reliable performance in medium-load, medium-speed applications
- Self-Lubricating: The dispersed lead phase provides inherent lubricity, offering protection during marginal lubrication or temporary loss of lubricant.
- Atsparumas korozijai: Good resistance to many corrosive environments, typical of bronze alloys.
Apribojimai
- not suitable for extreme load or shock service
- not a high-strength structural bronze
- It is not heat-treatable for major strengthening
- not ideal when welding is central to fabrication
- not the best choice if the application requires very high wear resistance under severe boundary lubrication
- Aplinkos problemos: Lead content raises environmental and health concerns, leading to regulations and a push for lead-free alternatives in some applications.
8. Applications of C93200 Leaded Tin Bronze
C93200 is used widely in components such as:
- general-purpose bushings
- diesel engine wrist-pin bushings
- fuel-pump bushings
- hydraulic press main linings
- machine-tool bearings
- main spindle bearings
- rolling-mill bearings
- roll-neck bearings
- trunnion bearings
- atraminės poveržlės
- siurblio sparnuotės
- water-pump bushings
- linkage bushings
- automobile fittings
- general machinery parts
9. C93200 vs. Competing Alloys
The table below compares C93200 su C95400 ir C95500, because these are two of the most practical competing cast copper alloys in bearing, dėvėti, and corrosion-resistant service.
| Comparison item | C93200 | C95400 | C95500 |
| Lydinių šeima / role | High-leaded tin bronze; SAE 660 bearing bronze used as a general-purpose bearing and bushing alloy. | Aliuminio bronza; a broad-use structural and wear bronze. | Nikelio aliuminio bronza; a severe-service bronze with strong marine and wear positioning. |
| Chemistry signature | Cu 81.0–85.0%, Pb 6.0–8.0%, Sn 6.3–7.5% | Cu 83.0% min., Al 10.0–11.5% | Cu 78.0% min., Al 10.0–11.5%, Ni 3.0–5.5% |
| Tankis | 8.91 g/cm³. | 7.45 g/cm³. | 7.53 g/cm³. |
| Elektros laidumas | 12% IACS. | 13% IACS. | 8% IACS. |
| Šilumos laidumas | 33.6 Btu/ft²·hr·°F. | 33.9 Btu/ft²·hr·°F. | 24.2 Btu/ft²·hr·°F. |
| Tamprumo modulis | 14,500 ksi. | 15,500 ksi. | 16,000 ksi. |
Typical room-temperature tensile strength |
35 ksi minimum in continuous cast condition. | 85 ksi minimum in continuous cast condition. | 95 ksi minimum in continuous cast condition. |
| Typical room-temperature yield strength | 20 ksi minimum in continuous cast condition. | 32 ksi minimum in continuous cast condition. | 42 ksi minimum in continuous cast condition. |
| Pailgėjimas | 10% minimumas. | 32% minimum in the continuous-cast standard row. | 42% minimum in the continuous-cast standard row. |
| Apdirbamumo įvertinimas | 70. | 60. | 50. |
| Casting characteristics | High casting yield; low drossing; medium fluidity; medium gassing; low shrinkage in solidification. | Low casting yield; high drossing; medium fluidity; medium gassing; high shrinkage in solidification. | Low casting yield; high drossing; medium fluidity; medium gassing; high shrinkage in solidification. |
Prisijungimas / Gaminimas |
Soldering excellent; brazing good; welding methods generally not recommended; stress relief at 500°F. | Soldering good; brazing good; gas-shielded arc and coated metal arc welding good; solution treatment available. | Soldering good; brazing fair; gas-shielded arc and coated metal arc welding good; solution treatment and annealing available. |
| Typical service emphasis | General-purpose bearings, įvorės, poveržlės, siurblio komponentai, automotive fittings, and medium-load wear service. | Weld guns, guoliai, bearing segments, large hold-down screws, riešutai, and industrial wear parts. | Jūrų techninė įranga, window hardware, muzikos instrumentai, guoliai, riešutai, and severe-service corrosion/wear parts. |
10. Išvada
C93200 leaded tin bronze, or SAE 660, has remained an industry standard for one simple reason: it works.
It combines the right mix of bearing performance, Aparatas, išliejamumas, and practical strength to solve a very common engineering problem efficiently.
C93200 is not a glamour material, and it is not a maximum-performance alloy. It is a reliable, well-balanced, highly serviceable bearing bronze.
That balance is the essence of its value. In engineering, the best material is often not the one with the most impressive single number, but the one that performs consistently across the full chain of casting, apdirbimas, susirinkimas, ir aptarnavimas.
DUK
What is the primary difference between C93200 and other bronzes?
The primary difference lies in its lead content (6-8%), which provides superior machinability and self-lubricating properties, making it ideal for bearing applications.
Other bronzes may prioritize strength (Pvz., aliuminio bronza) or corrosion resistance without the same level of lubricity.
Can C93200 be heat treated for hardening?
Ne, C93200 is not heat-treatable for hardening. Its mechanical properties are achieved in the as-cast condition. Any thermal processing is typically for stress relief only.
Is C93200 suitable for marine environments?
C93200 offers good corrosion resistance, including to saltwater, making it suitable for some marine applications, particularly for bearings and bushings that are not exposed to highly aggressive conditions or high flow rates where erosion-corrosion might be an issue.
Tačiau, for more demanding marine environments, specialized marine bronzes might be preferred.
What are the environmental concerns regarding C93200?
The lead content in C93200 raises environmental and health concerns, particularly regarding lead leaching and exposure.
Regulations in some regions are driving the adoption of lead-free alternatives, especially in potable water systems or applications with direct human contact.
