Bronze Bearing Materials: CuSn8 Wrapped Bushings, Graphite-Lubricated Bronze
Bronze Bearing Materials: CuSn8 Wrapped Bushings, Graphite-Lubricated Bronze
High-Performance Self-Lubricating Bronze Bushing Solutions & Technologies. Minimize downtime, extend service life, and reduce costs for dynamic applications.
Material Selection
Bronze Bearing Materials: CuSn8 Wrapped Bushings, Graphite-Lubricated Bronze, C46400 Naval Brass & Cast Alloy Machinability
Four material families cover most of the plain-bearing decisions our customers bring us: cold-formed CuSn8P wrapped bronze bushings built to the DIN 1494 / ISO 3547 family, graphite-impregnated and graphite-plugged cast bronze for dry high-load service, C46400 naval brass plate for seawater hardware, and the continuous-cast bronze alloys that machining cost really depends on. This guide consolidates the published engineering data for each, flags where figures disagree between sources, and states plainly what the data does not cover.
Read this first — scope of this document
This is a general engineering reference compiled from publicly published manufacturer datasheets and industry alloy tables. It is not a specification, a warranty, or a certificate.
- Values are approximate. Mechanical and physical properties vary with casting method, section size, temper, heat treatment and test direction. Always defer to the mill test certificate (MTC) supplied by your material vendor for any value you intend to design against.
- No certification conclusions are stated or implied. This document contains no military, automotive, food-contact, medical, nuclear, or aviation airworthiness-grade certification conclusions, and must not be read as evidence of conformity in any of those regulated domains.
- AMS 4880 is cited for data provenance only. Where an aerospace material specification is named, it appears solely as a published source for cast nickel-aluminium-bronze property data. It is not a conformance claim, not a qualification, and not an airworthiness statement of any kind.
1. Why bronze still wins in plain bearings
Rolling bearings get the attention, but for oscillating motion, shock loading, contaminated environments and locations nobody can reach with a grease gun, a bronze plain bearing is usually the more durable answer. Bronze brings a combination that is hard to substitute: high compressive strength, good thermal conductivity that carries frictional heat away from the contact, embeddability that lets dirt particles sink harmlessly into the surface instead of scoring the shaft, and corrosion resistance in seawater and process fluids.
The trade-off is real, too. A plain bearing typically has a higher starting torque than a rolling bearing and a somewhat lower mechanical efficiency. Non-self-lubricating types still need a lubrication regime. And efficiency depends on matching the material to the lubricant — the bearing material should offer good emergency-running behaviour, high wear resistance and high thermal conductivity, while the lubricant has to wet and coat the friction surface reliably.
Three variables dominate service life. The PV value — specific bearing load p multiplied by sliding speed v — has the largest influence, and life falls as PV rises. Friction coefficient depends on the material pairing, counter-surface roughness, specific load, sliding speed, bearing temperature and lubrication type. And the running-in period matters: during break-in, lubricant or part of the dry sliding layer transfers to the mating surface, filling and levelling its roughness peaks. Only after that transfer film exists does the low-friction, low-wear operating regime develop.
FB — Wrapped bronze
Cold-formed bronze strip with lubrication pockets or through-holes.
- Thin wall, compact housing
- Medium load, moderate speed
- Initial grease, long relubrication intervals
JDB — Graphite plugged
Cast bronze with solid graphite inserts in the sliding surface.
- Very high static load
- Low speed, oscillating, intermittent
- Dry running, no relubrication
SF — PTFE composite
Metal-backed PTFE-lined composite for maintenance-free duty.
- Very low friction
- Dry or marginally lubricated
- Automotive, hydraulics, general machinery
JF — Bimetal
Steel backing with sintered bronze or lead-bronze lining.
- High load and fatigue strength
- Shock loading
- Engines, chassis, agricultural equipment
2. CuSn8 / CuSn8P wrapped bronze bushings
A wrapped bronze bushing is cold-formed from a single strip of homogeneous tin bronze, then finished with diamond-shaped lubrication indents or through-holes across the bearing surface. Those indents act as grease reservoirs: they build a lubrication film quickly at the start of movement and then hold a reserve that stretches relubrication intervals well beyond a plain bore. The result is a thin-walled, high-load-capacity bearing that fits a small housing and installs with a simple press fit.
The strip material is CuSn8 or its higher-phosphorus variant CuSn8P, supplied to the composition limits of DIN 17662. Comparable designations are EN CW453K for CuSn8, EN CW459K for CuSn8P, and UNS C52100 as the nearest North American number.
2.1 Composition and physical properties
| Property | Value | Note |
|---|---|---|
| Copper (Cu) | Remainder | — |
| Tin (Sn) | 7.5 – 8.5 % | Solid-solution strengthening |
| Phosphorus (P) | 0.01 – 0.4 % | CuSn8P variant: 0.2 – 0.4 % |
| Zinc (Zn) | ≤ 0.2 % | Impurity limit |
| Iron (Fe) / Nickel (Ni) | ≤ 0.1 % / ≤ 0.2 % | Impurity limits |
| Lead (Pb) | ≤ 0.02 % | Effectively lead-free |
| Density | 8.8 g/cm³ | — |
| Melting point | 1040 °C | — |
| Young’s modulus | 115 GPa | — |
| Thermal conductivity | 67 W/m·K | — |
| Electrical conductivity | ≥ 13 % IACS | Soft temper; falls with cold work |
| Thermal expansion | 18.5 × 10⁻⁶ /K | 20 – 300 °C |
| Machinability | Not recommended | Formed and sized, not machined to shape |
2.2 Mechanical properties by temper
| Temper | Tensile Rm (MPa) | Yield Rp0.2 (MPa) | Elongation A50 | Hardness HV |
|---|---|---|---|---|
| R370 | 370 – 450 | ≤ 300 | ≥ 50 % | 90 – 120 |
| R450 | 450 – 550 | ≥ 280 | ≥ 20 % | 135 – 175 |
| R540 | 540 – 630 | ≥ 460 | ≥ 13 % | 170 – 200 |
| R600 | 600 – 690 | ≥ 530 | ≥ 5 % | 190 – 220 |
| R660 | 660 – 750 | ≥ 620 | ≥ 3 % | 210 – 240 |
| R740 | ≥ 740 | ≥ 700 | ≥ 2 % | ≥ 230 |
2.3 Operating limits for perforated wrapped bronze
| Parameter | Value |
|---|---|
| Maintenance class | Low-maintenance — initial lubrication required |
| Specific static load capacity | ≤ 120 N/mm² |
| Specific dynamic load capacity | ≤ 40 N/mm² |
| Sliding speed | ≤ 2.5 m/s |
| Friction coefficient µ | 0.05 – 0.20 (lubrication dependent) |
| Service temperature | −40 °C to +250 °C |
| Maximum PV value | 2.8 N/mm²·m/s |
| Shaft material | Steel, hardened or untreated, roughness ≤ Rz 6.3 |
| Lubrication | Oil or grease both suitable |
Data note — friction coefficient
Published friction ranges for this bushing type are not uniform. Perforated low-maintenance grades are commonly listed at µ = 0.05 – 0.20, while some distributor listings for the non-perforated variant quote 0.05 – 0.12. The wider band reflects lubrication condition, not a different alloy. Do not design a friction-sensitive mechanism on the lower figure without testing your own lubricant and counter-surface.
2.4 Standard product forms
Wrapped bronze is produced in four standard geometries, with stamped and formed specials made to drawing. Non-standard sizes, flanged variants, thrust faces and custom lengths are routine.
| Product type | Typical series code | Common designation |
|---|---|---|
| Cylindrical bushing | FB / BMZ | Plain wrapped bush |
| Flanged bushing | FB-F / BMB | Flanged wrapped bush |
| Thrust washer | FB-W / BMA | Thrust washer, strip form |
| Strip | FB-S / BMS | Bronze strip for cut lengths |
3. Fits, tolerances & mounting practice
Wrapped bushes are dimensioned so that after pressing into an H7 housing bore they close up round and hold a proper interference fit. The bore then lands on H9, and the shaft is normally ground to f7. Slight departures from perfect roundness and an open butt joint are inherent to the wrapping process and are accommodated within the standard — they are not defects.
| Feature | Recommendation |
|---|---|
| Housing bore | H7 |
| Bushing bore after mounting | H9 |
| Shaft tolerance | f7 |
| Housing lead-in chamfer | ≈ 1.5 mm × 15° – 45° |
| Shaft lead-in chamfer | 5 mm × 15°, edges rounded |
| Flange seat chamfer | 1.0 × 45° (1.5 – 2 × 45° on larger sizes) |
| Assembly tool | Fitting mandrel; mounting ring advised above 50 mm bore |
| Outer surface | Light greasing may be needed at press-fit |
Press the bush in with a mandrel so the force goes straight down the axis. Sharp shaft edges will score the sliding surface during assembly and shorten bearing life, so chamfer or round every shaft end. The published inside-diameter tolerances are only achieved when the bush is correctly installed and the housing is bored to the middle of its tolerance band.
Above roughly 80 °C, remember bronze expands at about 18 × 10⁻⁶ /K. Thermal growth has to be built into the clearance calculation, or the bearing will tighten as the machine warms up.
3.1 Getting the lubrication regime right
Oil suits higher speeds and loads and works at low speeds too; molybdenum disulphide or graphite additives can improve film adhesion and smooth the sliding surfaces. Grease is the usual answer for low speeds, oscillating movement, shock loading, or wherever a full fluid film cannot be established. Use only good-quality plain-bearing grease, avoid formulations with more than 2 % solid additives — they accelerate wear — and never lubricate polymer-lined bearings with molybdenum-sulphide grease. Dry lubricant, in the form of graphite or MoS₂ inserts or coatings, is the route for high temperature, emergency running, or genuine fit-and-forget service.
4. Graphite-lubricated bronze & slide plates
Graphite-lubricated bronze takes two forms that solve the same problem from different directions. Graphite-plugged cast bronze (our JDB series) is a cast bronze body drilled with a pattern of holes filled with solid graphite plugs. Graphite-impregnated bronze slide plate is a machined cast-bronze plate carrying solid graphite inserts in grooved patterns, normally bonded or mechanically fixed to a carbon-steel backing plate for field welding.
In both, the bronze carries the load and the graphite carries the lubrication. A graphite transfer film forms between the bearing and its mating surface at the first relative movement, giving a low coefficient of friction without a drop of oil. Because the lubricant is distributed through the thickness of the component rather than sitting on the surface, lubrication performance does not degrade as the part wears.
4.1 Typical slide-plate bronze — composition and strength
The bronze used for graphite-impregnated slide plates is commonly specified as equivalent to UNS C92400, a leaded tin bronze. The composition below is the published C92400 range and is consistent with the figures printed on typical slide-plate technical bulletins.
| Element | Min % | Max % |
|---|---|---|
| Copper (Cu) | 86.0 | 89.0 |
| Tin (Sn) | 9.0 | 11.0 |
| Lead (Pb) | 1.0 | 2.5 |
| Zinc (Zn) | 1.0 | 3.0 |
| Nickel (Ni) | — | 1.0 |
| Iron (Fe) | — | 0.25 |
| Antimony (Sb) | — | 0.25 |
| Sulphur (S) / Phosphorus (P) | — | 0.05 |
| Aluminium (Al) / Silicon (Si) | — | 0.005 |
| Property | Slide-plate bulletin | Cross-check |
|---|---|---|
| Tensile strength, min. | 40 ksi (≈ 275 MPa) | EN CC492K continuous cast: Rm 270 MPa |
| Yield strength, min. | 18 ksi (≈ 125 MPa) | EN CC492K continuous cast: Rp0.2 130 MPa |
Data note — C92400 equivalence is approximate
The nearest European designation, EN 1982 CC492K (CuSn7Zn2Pb3-C, formerly BS 1400 LG4), is quoted as the C92400 equivalent but its tin range is 6.0 – 8.0 %, materially lower than C92400’s 9.0 – 11.0 %. Treat cross-system “equivalents” in this family as indicative. Confirm composition and mechanicals against the actual mill certificate before substituting one for the other.
4.2 Published assembly rating, and the temperature caveat that matters
A standard graphite-bronze slide-plate assembly — bronze plate combined with a carbon-steel backing plate for field welding — is commonly rated for loads up to 5 000 psi and temperatures up to 1 100 °F (593 °C). That rating is the headline number on most slide-plate bulletins, and it is also the number most often applied without thinking.
Caution — graphite oxidises in air
Graphite begins oxidising to CO from roughly 400 °C and to CO₂ above about 500 °C, with severe degradation reported beyond 700 °C. Practical upper limits for graphite lubrication in air are therefore generally quoted in the 500 – 600 °C band, and at least one graphite-bushing manufacturer advises staying below 500 °F in oxygen-rich conditions. Treat 1 100 °F as an intermittent upper bound, not a continuous operating temperature. Actual capability depends on atmosphere, load, duty cycle and ventilation, and must be validated by testing for any sustained high-temperature application.
Where the plate is bonded rather than plugged, remember that the load-bearing capacity of graphite itself is not temperature-sensitive — the adhesive is. Above about 500 °F it is good practice to add mechanical fasteners such as counter-sunk screws to hold the graphite in place.
4.3 Why specifiers choose graphite bronze
No lubrication logistics
Maintenance-free with no grease nipples, lines or reservoirs — no relubrication schedule to police.
Wear-independent lubrication
Graphite is distributed through the section, so lubricating performance does not fall off as the surface wears.
Contamination control
Dry surfaces do not attract dust and grit, which matters in dirty or hygiene-sensitive plants.
High load, low speed
Purpose-built for heavy loads at low velocity, and for oscillation and intermittent motion.
Extended service life
Reduced wear on both the plate and its counter-face, particularly where an oil film cannot be maintained.
Wide temperature window
Usable well beyond the limits of oil and grease, subject to the oxidation caveat above.
4.4 Typical applications
Civil and structural: highway, overpass and railway bridge bearings; cross-beam and girder slip joints; roof slabs and corbels; vibration pads; large door and dome structures. Industrial: heat exchangers, dust collectors, heavy machinery, refinery equipment, penstocks, pressure vessels, pipelines, air preheaters, storage tanks, transmission towers and offshore structures. Equipment: die and mould guide systems, hydraulic cylinder guides, toggle and clamping mechanisms, and any pivot where relubrication is impractical.
4.5 Ordering and installation essentials
- Size the pair, not one plate. The upper plate is normally larger than the lower, so quote both sets of dimensions plus base-plate thickness.
- Weld with a lip. Welding heat can break the bond between the low-friction layer and its backing, so build in a lip — 6 mm (¼ in) is adequate for most work. Tack-weld along the outside edge for a solid installation; a full 6 mm fillet prevents water seeping between plate and structure.
- Concrete installation. Anchor bolts are integrated into the base plate and tied into the form rebar or cast directly into the concrete.
- Bolting instead of welding. Where hot work is not permitted, bolting is the standard substitute.
5. Self-lubricating bronze in oil & gas service
Oil and gas is a demanding customer for bronze: abrasive and corrosive fluids, continuous duty, remote sites, and a maintenance window that costs far more than the part. Machined bronze and brass components are used throughout the drilling, completion and production chain, and the same component families keep recurring.
| Service area | Typical bronze components |
|---|---|
| Pressure pumping | Frac pump liners, mud pump and stimulation pump liners, fluid-end accessories |
| Compressors | Wrist-pin bushings, connecting-rod bushings, crosshead components |
| Sealing & stuffing boxes | Lantern rings, throat bushings, stuffing box components, adapter rings, spacers |
| Valves & flow control | Valve and fluid-end accessories, seats, guides, trim wear parts |
| Drilling & offshore | Offshore and deep-well drilling components, rig wear parts |
Selection in this sector is driven less by catalogue load ratings than by production control. Each job tends to be pre-planned against a documented control plan so that results are repeatable and deliveries land on time, and the machining sequence is simulated before the quote is issued so cycle times — and therefore prices — are realistic. Inventory management arrangements often matter more than unit price: holding consignment stock can compress lead times from weeks to days.
For VIIPLUS customers in this sector, the practical shortlist is usually JDB graphite-plugged bronze where lubrication access is poor or the fluid would wash grease out, and C95400 aluminium bronze or a nickel-aluminium bronze where seawater corrosion, cavitation and fatigue resistance dominate.
6. C46400 naval brass plate
Naval brass is the alloy you reach for when a component lives in seawater. C46400 substitutes 0.5 – 1.0 % tin for part of the zinc, and that tin addition gives the alloy inherent resistance to dezincification — the selective leaching of zinc that destroys ordinary brasses in seawater, particularly at elevated temperature. On top of that it resists wear, fatigue, galling and stress corrosion cracking, and it combines useful strength with excellent hot formability.
6.1 Composition
| Element | Min % | Max % |
|---|---|---|
| Copper (Cu) | 59.0 | 62.0 |
| Tin (Sn) | 0.5 | 1.0 |
| Iron (Fe) | — | 0.10 |
| Lead (Pb) | — | 0.20 |
| Zinc (Zn) | Remainder | |
6.2 Thermal treatment and physical properties
| Property | Value | Metric equivalent |
|---|---|---|
| Annealing temperature | 800 – 1 100 °F | 427 – 593 °C |
| Hot working temperature | 1 200 – 1 500 °F | 649 – 816 °C |
| Melting point — liquidus | 1 650 °F | 900 °C |
| Melting point — solidus | 1 630 °F | 885 °C |
| Density | 0.304 lb/in³ | 8.41 g/cm³ |
| Specific gravity | 8.41 | 8.41 |
| Electrical conductivity | 26 % IACS | — |
| Thermal conductivity | 67 Btu·ft/(hr·ft²·°F) | 116 W/m·K |
| Thermal expansion | 11.8 × 10⁻⁶ /°F (68 – 572 °F) | 21.2 µm/m·K |
| Specific heat capacity | 0.09 Btu/lb/°F | 380 J/kg·K |
| Modulus of elasticity (tension) | 15 000 ksi | 103 GPa |
| Modulus of rigidity | 5 600 ksi | 38.6 GPa |
| Machinability rating | 30 % | vs C36000 = 100 |
Correction — solidus temperature
Some naval-brass plate datasheets print the solidus as 1 650 °F, identical to the liquidus, which is physically inconsistent. Authoritative sources give solidus 1 630 °F (885 °C), liquidus 1 650 °F (900 °C). The corrected pair is used above. This matters in practice: the 20 °F difference is the whole hot-working window for brazing and heat treatment, and a design built on 1 650 °F solidus would have no margin at all.
6.3 Applicable ASTM specifications and typical uses
Plate is supplied to ASTM B171; rod and shapes to ASTM B21 and ASTM B124; die forgings to ASTM B283. Typical service includes marine hardware, propeller shafts, valve stems, balls, nuts, bolts and rivets, condenser plates, structural members, welding rod and general seawater-exposed hardware.
Standard stocked forms are plate and sheet in widths of 37 in, 48 in and 61 in by 120 in long, with greater sizes available to order. Waterjet cutting is a cost-effective route to precision blanks, near-net-shape parts and semi-finished components, and it avoids the heat-affected zone that thermal cutting would leave.
7. Cast bronze machinability ratings — 33 alloys compared
Machinability ratings are relative percentages benchmarked against UNS C36000 free-cutting brass at 100. A rating of 70 means the alloy machines roughly 70 % as well as C36000 under comparable conditions. This is a machining-cost indicator — it correlates with tool wear, chip breakability and achievable surface finish. It says nothing about load capacity, wear resistance or corrosion behaviour, and a low rating is frequently the price of exactly the properties you are buying the alloy for.
Cast bronze alloy machinability ratings (C36000 free-cutting brass = 100)
Cast bronze alloy machinability ratings (C36000 free-cutting brass = 100)
80–90 Excellent40–70 Good to moderate8–30 DifficultScale: 0–100, C36000 = 100
| UNS No. | Designation | Machinability | Practical implication |
|---|---|---|---|
C84400 |
Leaded red brass | 90 | Fastest cutting; low tool wear |
C89831 |
Federalloy | 85 | Lead-free substitute with excellent machining |
C83600 |
Leaded red brass | 84 | Low-to-medium load bushings; better corrosion than C93200 |
C89833 |
Federalloy | 81 | Lead-free, good machinability |
C94300 |
High-leaded tin bronze | 80 | Maximum embeddability; soft lead matrix |
C93800 |
High-leaded tin bronze | 80 | High-lead bearing bronze |
C93700 |
High-leaded tin bronze | 80 | Anti-friction, dirt-tolerant |
C93600 |
High-leaded tin bronze | 80 | High-lead, moderate strength |
C89320 |
Bismuth tin bronze | 80 | Bismuth replaces lead for regulatory compliance |
C89325 |
Federalloy | 80 | Lead-free bearing alloy |
C85700 |
Leaded red brass | 80 | General hardware and fittings |
C89844 |
Federalloy | 70 | Lead-free, good all-round |
C97300 |
Leaded tin bronze | 70 | Nickel-bearing; decorative and marine |
C89835 |
Federalloy | 70 | Lead-free structural grade |
C93200 |
Leaded tin bronze (SAE 660) | 70 | The general-purpose bearing workhorse |
C97600 |
Leaded nickel bronze | 70 | Nickel silver type; corrosion resistant |
C87850 |
Eco brass | 70 | Lead-free silicon-brass alternative |
C95400 |
Aluminium bronze | 60 | Heavy-duty; carbide tooling usually warranted |
C95410 |
Aluminium bronze | 60 | Continuous-cast alternative to C95400 |
C95300 |
Aluminium bronze | 55 | Heat-treatable; high strength |
C99500 |
Nickel-aluminium bronze | 50 | High strength, cavitation resistant |
C95520 |
Nickel-aluminium bronze | 45 | Quench-hardened and tempered condition only |
C92900 |
Leaded nickel-tin bronze | 40 | High strength bearing bronze |
C90300 |
High tin bronze | 30 | Seawater-resistant pump and valve parts |
C90500 |
High tin bronze | 30 | Good pressure tightness |
C86500 |
Manganese bronze | 20 | High strength; slow cutting |
C91700 |
High tin bronze | 20 | High tin content; wear resistant |
C90700 |
High tin bronze | 20 | Gear and heavy bearing bronze |
C95200 |
Aluminium bronze | 20 | Lower-aluminium, tough grade |
C95800 |
Nickel-aluminium bronze | 20 | Propellers and seawater castings |
C91100 |
High tin bronze | 10 | Very high tin; difficult machining |
C95900 |
Aluminium bronze | 10 | Very hard; grinding often preferred |
C86300 |
Manganese bronze | 8 | Highest strength, slowest machining; needs rigid setup |
Data note — two figures worth checking before you quote
Published machinability values for individual alloys are not perfectly consistent between sources. Two examples we see most often: C86300 manganese bronze appears as 8 in the alloy-bar chart reproduced here, while some machining guides list 30. C95520 nickel-aluminium bronze appears as 45 here, while at least one supplier datasheet publishes 50. Both discrepancies are large enough to change a machining quotation. Use one source consistently and confirm against your own shop data.
Data note — AMS 4880, cited for data provenance only
AMS 4880 is an SAE aerospace material specification covering cast nickel-aluminium bronze, and it is referenced here solely as one published source for the property data of that alloy family. Published UNS-to-AMS mappings disagree: several specialist bronze manufacturers map AMS 4880 to C95510 and AMS 4881 to C95520, while some supplier datasheets associate AMS 4880 with C95520. The row above is C95520. Nothing in this document asserts conformity to AMS 4880 or to any other aerospace, military or regulated specification. Verify the mapping and the current revision against the SAE document itself before using it for procurement.
8. Machining notes by alloy family
Bronze is generally a forgiving material to machine, but the spread from 90 to 8 in the table above is the difference between a profitable part and a problematic one. A few rules hold across the range.
- Tooling. Use sharp carbide inserts; aluminium and manganese bronzes are abrasive and blunt HSS quickly. Uncoated or TiN/TiCN-coated carbide works well, and polished flutes help with chip evacuation on the gummier leaded grades. Positive rake angles reduce cutting forces and built-up edge.
- Cutting fluid. Soluble oil or semi-synthetic coolant improves finish, extends tool life and — most importantly — carries heat away. Avoid sulfurised cutting oils on copper alloys if staining matters.
- Thermal growth. Copper alloys expand significantly when heated. A part machined hot will contract below tolerance once it cools, so flood-cool and let parts stabilise before finish-passing to a tight tolerance.
- Operations. Turning for bores, shoulders, grooves and chamfers; milling for slide plates, pockets, slots and mounting holes; drilling for lubrication and dowel holes; boring to size internal diameters; threading where required; grinding after machining where tolerance and finish are critical.
- Slow-cutting alloys. For C86300, C95900 and the nickel-aluminium bronzes, plan on reduced speeds, rigid workholding and realistic cycle times — and price accordingly.
9. Selection framework
There is no single best bronze. The right choice is the alloy whose failure mode best matches your operating conditions — start from what is most likely to kill the bearing, then work backwards.
| Dominant condition | Start here | Why |
|---|---|---|
| General purpose, medium load and speed | C93200 (SAE 660) | Balanced strength, wear and machinability; forgiving of dirty or intermittent lubrication |
| Extreme static or low-speed load | C86300 manganese bronze | Highest strength and hardness; needs a hardened shaft and clean lubrication |
| Seawater, cavitation or erosion | C95400 aluminium bronze | Superior seawater corrosion, erosion and fatigue resistance |
| Dry or inaccessible lubrication | JDB graphite-plugged bronze | Solid lubricant through the section; no relubrication, no contamination pickup |
| Thin wall, compact housing, cost-driven | FB wrapped CuSn8P bronze | Minimal radial space, low unit cost, extended relubrication intervals |
| Low friction, dry running, moderate load | SF PTFE composite | Very low coefficient of friction without any lubricant |
| Shock loading and high fatigue demand | JF bimetal | Steel backing carries fatigue load; bronze lining carries the bearing duty |
| Seawater hardware and structural plate | C46400 naval brass | Dezincification resistance at elevated seawater temperature |
| Lead content restricted | C898xx / C893xx / C87850 | Lead-free and bismuth-bearing alternatives with good machinability |
Whatever the starting point, validate the shortlist against the full set of variables: material and surface roughness of both sliding partners, specific bearing load, sliding speed, PV value, load-zone allocation, duty cycle, temperature, lubrication regime and operating environment. Selecting on dimensions alone is the most common cause of premature bearing failure we see.
10. Frequently asked questions
What is the difference between CuSn8 and CuSn8P bronze for wrapped bushings?
CuSn8 (EN CW453K, comparable to UNS C52100) is a wrought tin bronze with 7.5–8.5 % tin. CuSn8P (EN CW459K) is the higher-phosphorus variant at 0.2–0.4 % phosphorus, specified where improved wear resistance and sliding behaviour are needed. Both are supplied as strip to DIN 17662 composition limits and cold-formed into wrapped bushes; neither is normally finish-machined from solid.
Is DIN 1494 still a valid standard for wrapped bronze bushes?
DIN 1494 was superseded by the DIN ISO 3547 series for wrapped bushes. DIN ISO 3547-1 covers dimensions and replaced DIN 1494-1; the series also covers test data for outside and inside diameters, lubrication holes, grooves and indentations, materials, checking of outside and inside diameters, and measurement of wall thickness of thin-walled bushes. Many suppliers still print “DIN 1494 / ISO 3547” because both designations remain widely recognised in procurement.
How should I read a cast bronze machinability rating?
Machinability ratings are relative percentages benchmarked against UNS C36000 free-cutting brass at 100. A rating of 70 means the alloy is roughly 70 % as machinable as C36000 under comparable conditions. Ratings indicate relative tool wear, chip formation and achievable surface finish — they are a machining-cost indicator, not a mechanical or wear-performance property.
Can graphite-lubricated bronze run at 1100 °F?
Some graphite bronze slide-plate assemblies are rated to 1100 °F (593 °C), but graphite oxidises in air from roughly 400–500 °C and degrades severely beyond about 700 °C. Treat a 1100 °F figure as an intermittent upper bound that must be validated against actual atmosphere, load, duty cycle and ventilation. Sustained high-temperature service needs application-specific testing.
Why does C46400 naval brass resist seawater better than ordinary brass?
C46400 contains 0.5–1.0 % tin substituted for part of the zinc. The tin addition gives the alloy inherent resistance to dezincification — the selective leaching of zinc that attacks plain brasses in seawater, particularly at elevated temperature. C46400 also resists wear, fatigue, galling and stress corrosion cracking.
Should I choose a wrapped bronze bushing or a cast graphite-plugged bronze bushing?
Wrapped bronze (FB type) is thin-wall, compact and low-cost, suits medium loads and moderate speeds, and needs initial greasing with extended relubrication intervals. Cast graphite-plugged bronze (JDB type) carries much higher static loads, runs dry with no relubrication, tolerates oscillating and intermittent motion, and suits locations where lubrication access is difficult or contamination would be a problem.
What shaft specification does a wrapped bronze bushing need?
Use steel, hardened or untreated, at f7 tolerance with surface roughness no coarser than Rz 6.3. Chamfer or round the shaft ends — sharp edges damage the sliding surface during assembly. Good surface finish on the counter-face directly extends bearing life because it shortens the running-in period.
11. Engineering reference disclaimer
Scope, accuracy and limitations
- General engineering reference only. This document consolidates data from publicly published manufacturer datasheets, mill datasheets and industry alloy tables. It is provided for preliminary material comparison and general engineering information.
- Values are approximate and condition-dependent. Chemical composition, mechanical properties and physical properties vary with casting method (sand, centrifugal, continuous or investment), section size, temper, heat treatment, test direction and testing standard. They are not guaranteed values and are not suitable for specification purposes.
- The supplier’s mill test certificate governs. For any value used in design, procurement or contractual acceptance, defer to the mill test certificate (MTC) / certificate of analysis issued by the supplying mill or vendor for the specific heat and lot supplied.
- No certification conclusions. This document contains no military, no automotive, no food-contact, no medical, no nuclear and no aviation airworthiness-grade certification conclusions. It does not state, imply or evidence conformity to any specification, code, directive or regulatory regime in those domains, and it must not be used as such.
- AMS 4880 — data provenance only. AMS 4880 is cited solely as one published source of material property data for cast nickel-aluminium bronze. Reference to it is not a conformance claim, not a material qualification and not an airworthiness or other certification conclusion of any kind. Published UNS-to-AMS mappings differ; verify against the current SAE document.
- No federal or military specifications are referenced. This document deliberately contains no references to any federal or military specification of any kind, and makes no statement of conformity to any of them. Where such specifications exist for the alloys discussed, their absence here is intentional and does not indicate either compliance or non-compliance.
- Application validation is the user’s responsibility. Bearing selection must be verified against actual operating conditions including load, speed, PV value, temperature, shaft condition, lubrication regime, environment and expected service life. VIIPLUS accepts no liability for selections made from this document without such verification.
- Trademarks. Third-party product and alloy designations are the property of their respective owners and are used for identification and technical comparison only.
Talk to a bronze bearing engineer
Send us your load, speed, temperature and duty cycle — or just a drawing — and we will come back with a shortlisted alloy, a manufacturable design and a realistic quotation. Involving us early in the design stage usually saves cost, extends service life or both.
Third-party product names and designations referenced for technical comparison remain the property of their respective owners.
Metal Bushing (Lubricated Metal) -Self-Lubricating Bushing Materials
Bushings are specialized, self-lubricating metal components widely utilized across various industries due to their durability and low maintenance requirements. Self-lubricating metal bushings are engineered to function without additional lubrication in numerous applications, thereby minimizing maintenance needs. These bushings are available in various series and configurations, such as flanged bushings and split bearings, to meet specific application requirements.
Metal-Polymer Anti-Friction Plain Bearings
Metal-Polymer Composite Self-lubricating Bushing Material
Steel Back + Porous Bronze Sinter + PTFE
