Custom plain bearings
The demand for custom non-standard plain bearings is increasing. We can manufacture copper alloy materials to meet China’s national standards as well as the ASTM (UNS, SAE), EU, and JIS standards.
Bespoke plain bearings
viiplus collaborates with customers to find tailored solutions, offering plain bearings in various materials, sizes, tolerances, and designs.
Timely Delivery
Committed to meeting tight deadlines without compromising on quality, we ensure reliable and efficient production timelines.
Versatility
Capable of handling both small-scale and high-volume orders, we provide seamless support for projects of any size. Additionally, we can develop custom copper alloy materials based on specific customer requirements and drawings.
Specialized in oil-free self-lubricating bushings
A practical engineering reference for oil-free self-lubricating bushings made from copper alloys — covering phosphor-bronze (CuSn8 / EN CW453K) wrapped bushes and inlaid graphite copper-alloy bearings, with material data, tolerance practice, selection method and application guidance.
Custom Machined Bronze Parts & Bearings
What is a copper-alloy oil-free self-lubricating bushing
An oil-free self-lubricating bushing is a plain bearing designed to run with little or no external oil or grease. In copper-alloy variants the bearing body is a copper-based material, and the lubricant is supplied either by a thin functional layer (oil pockets or a polymer/PTFE running surface) or by solid lubricant set into the metal. Two families dominate, and they should not be selected interchangeably:
Wrapped phosphor-bronze bush — a thin-wall component rolled from phosphor-bronze strip (CuSn8 / EN CW453K), typically with oil pockets or a polymer running layer. Built to ISO 3547 / DIN 1494. Suited to grease or oil supply and moderate loads and speeds.
Inlaid graphite copper-alloy bushing — a solid copper-alloy base (high-tensile brass or cast bronze) with solid graphite plugs set into machined pockets. It runs without external lubrication and is suitable for heavy-load, low-speed or intermittent/oscillating motion.
Oilless Bushing Material, Machining Parts
Why copper alloy is used
Copper alloys are selected for oil-free bushings because of a combination of properties that matter at the sliding interface:
- Good sliding and anti-seizure behaviour — phosphor bronze and cast bronzes form a stable interface with hardened shafts.
- Wear resistance — relevant for reciprocating, start-stop and oscillating motion where an oil film is difficult to maintain.
- Corrosion resistance — bronze performs in industrial atmospheres, fresh and sea water, and many neutral/alkaline media.
- Mechanical backing — the copper-alloy body carries heavy static and shock loads that polymer or thin coatings cannot.
- Compact envelope — a solid bushing is thinner than many rolling-bearing arrangements, saving space in equipment design.
Grade equivalence
| Role in bushing | China GB/T | EN | UNS / ASTM | DIN | BS | Notes |
|---|---|---|---|---|---|---|
| Wrapped bronze strip | QSn8-0.3 comparable | CW453K | C52100 | 2.1030 | PB104 | CuSn8 phosphor bronze; 8% Sn |
| High-tensile brass base (inlaid type) | — | — | C86300 | — | — | CuZn25Al5Mn4Fe3 manganese bronze |
| Cast bronze base (graphite-plugged) | ZCuSn5Pb5Zn5 comparable | — | C83600 | — | — | Common tin bronze for plugs |
| Aluminium-bronze base (graphite-plugged) | — | — | C95400 / C95500 | — | — | Higher temperature and corrosion resistance |
Cross-references are approximate; confirm the exact grade and condition against the applicable procurement standard before design release.
Material technical data
Temper strongly affects strength: soft-annealed and hard tempers differ by roughly a factor of two in tensile strength, so the temper must always be stated for CuSn8 / EN CW453K.
3.1 CuSn8 / EN CW453K composition
| Element | Cu | Sn | P | Zn | Fe | Ni | Pb |
|---|---|---|---|---|---|---|---|
| Content | remainder | 7.5–8.5 | 0.01–0.40 | ≤0.20 | ≤0.10 | ≤0.20 | ≤0.02 ref. grade |
3.2 CuSn8 mechanical properties by temper
| Temper (ref.) | Tensile Rm (MPa) | Yield Rp0.2 (MPa) | Elong. A50 (%) | Hardness HV |
|---|---|---|---|---|
| Soft annealed (R370) | 370–450 | ≤300 | ≥50 | 90–120 |
| Half-hard (R450) | 450–550 | ≥280 | ≥20 | 135–175 |
| Hard (R540–R660) | 540–750 | ≥460–620 | ≥3–13 | 170–240 |
Values are indicative of strip product; finished bushing properties depend on forming, heat treatment and any inlay process.
3.3 CuSn8 physical properties
| Density | Melting point | Young’s modulus | Thermal cond. | Electrical cond. | CTE (20–300°C) | Specific heat |
|---|---|---|---|---|---|---|
| 8.8 g/cm³ | ~1040 °C | 115 GPa | 67 W/(m·K) | ≥7.5 MS/m (≥13% IACS) | 18.5×10−6/K | 0.377 kJ/(kg·K) |
3.4 Operating envelope by bushing family
The figures below are catalog-indicative and differ by family and supplier. They are not to be averaged across families; the lower bound should be used for screening.
| Parameter | Inlaid high-tensile-brass class lighter duty | Cast-bronze graphite-plugged heavy duty | Wrapped CuSn8 bronze per ISO 3547 |
|---|---|---|---|
| Maximum surface pressure P | 20–29 N/mm² | ~100–120 N/mm² (some variants higher) | Static ~120 N/mm² / dynamic ~40 N/mm² |
| Maximum sliding speed | 0.35–1.0 m/s (by lubrication) | ~0.5 m/s dry (higher lubricated) | ~2.5 m/s |
| Maximum PV value | 1.1–2.0 N/mm²·m/s | ~1.5–1.65 N/mm²·m/s (dry) | ~2.8 N/mm²·m/s (grease) |
| Temperature range | −40 to +150 °C | −40 to +300 / +400 °C (source-dependent) | −100 to +200 °C |
| Dry friction coefficient | not separately published for this class | ~0.08–0.18 | ~0.05–0.25 |
| Lubrication | Self-lubricating (inlaid solid lubricant) | Self-lubricating (solid graphite) | Grease/oil or polymer-assisted |
Forms and customization
Copper-alloy oil-free bushings are supplied in several geometries:
- Straight (cylindrical) bush — the most common form.
- Flanged bush — with a locating flange for axial positioning.
- Thrust washer / flange plate — for axial loads.
- Custom shapes — plates, strips and special sections for guides and wear pads.
Inner diameters are commonly held to tolerance class 7 (F7) for precision-machined inlaid bushings, with outer diameter around m6, housing H7 and shaft f7. Wrapped bushes follow the ISO 3547 / DIN 1494 tolerance practice (housing H7, mounted bore approximately H9, shaft f7), summarised in the selection guide and FAQ.
Manufacturing process (inlaid copper-alloy bushing)
A representative manufacturing route for the inlaid solid-lubricant copper-alloy bushing is:
- Drill / machine lubricant pockets — holes or slots are machined into the copper-alloy semi-finished bushing to receive the solid lubricant.
- Mix adhesive — an epoxy resin adhesive and curing agent are blended at a fixed ratio (commonly about 6:1).
- Inlay solid lubricant — graphite is coated with the adhesive and set by hand into the pockets, then naturally air-cured.
- Machining / turning — the body is turned or milled to final dimensions, producing chips and fine metal dust as by-products.
- Grinding and cleaning — ceramic media and a brightening agent are used to improve surface finish; the part is then washed to remove residues and oil.
- Rust-proof treatment — a room-temperature oil dip protects the surface during storage and transport.
- Inspection and packing — dimensions and appearance are checked before packing.
Process details vary by manufacturer; confirm the actual process with the supplier.
type of Custom Bearings & Bushings, Flanged Bearings, Custom Oilless Bronze Bushings, Custom Sliding Bearing
Custom Bearings & Bushings Materials & Alloys We Machine
Application matrix
| Equipment | Position | Motion | Load / speed | Environment | Recommended family |
|---|---|---|---|---|---|
| Injection moulding machine | Toggle-link / tie-bar bush | Reciprocating / oscillating | Heavy, low speed | High temperature near barrel | Cast-bronze graphite-plugged |
| Excavator / construction machinery | Boom and arm joints | Oscillating, shock | Heavy, intermittent | Dust, outdoor | Cast-bronze graphite-plugged |
| Material handling | Chain conveyor, guide | Continuous / sliding | Moderate | General | Inlaid brass or wrapped CuSn8 |
| Steel plant | Furnace car, roller | Slow rotation | Heavy, high temp | High temperature | Cast-bronze graphite-plugged |
| Hydropower / gate dam | Trunnion, guide | Oscillating, infrequent | Heavy | Water, submerged | Graphite-plugged (corrosion-resistant base) |
| Marine deck equipment | Crane, winch, rudder arm | Oscillating | Heavy | Sea water | Aluminium-bronze graphite-plugged |
| General machinery | Guide, linear slide | Linear / rotary | Light–moderate | Standard | Wrapped CuSn8 or inlaid brass |
Material Selection
Bronze Alloy Composition
Casting
Centrifugal casting, continuous casting
Machining
Precision Machining
Quality Inspection
Material Testing, Surface Inspection
