VIIPLUS SOLUTIONS · Plain Bearing Reference

CuZn25Al5 Turned Bronze Sliding Bearings — Material Data, Limits and Selection (DIN 1850 / ISO 4379)

A reference guide to maintenance-type turned (solid, machined) bronze sliding bearings in CuZn25Al5 (CC762S, DIN 2.0598): composition, mechanical and physical properties, load and speed limits, tolerances, mounting, and a comparison with other standard bronze bearing alloys.

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1. What is a CuZn25Al5 turned bronze sliding bearing

A turned bronze sliding bearing is a solid (not rolled/wrapped) plain bearing bush machined from a cast bronze bar or tube. The CuZn25Al5 grade is a high-strength manganese bronze (special brass) and is a common standard alloy for this product family. The bearings are produced to order and supplied as cylindrical bushes, flanged bushes, thrust washers and strips; special dimensions are available.

This variant is a maintenance-requiring sliding bearing: oil or grease lubrication is needed for function and service life. It is suited to operation in contaminated environments, offers corrosion resistance, and is insensitive to shock loads. Additional lubrication grooves or holes reduce relubrication intervals and improve lubricant distribution across the sliding surface.

The product is specified against DIN 1850 and ISO 4379:2018 (solid bronze plain bearing bushes). Material is a cast copper alloy in accordance with ISO 4382-1 (or a wrought alloy to ISO 4382-2).

2. Grade equivalence

The values below are composition-family equivalences used for material identification and sourcing. Confirm the applicable specification and temper for the actual part before design release.

The values below are composition-family equivalences. Confirm the applicable specification and temper for the actual part before design release.

CuZn25Al5Mn4Fe3-C is among the higher-strength cast special brasses. Under dynamic load and vibration a tin bronze (for example CuSn12) is often the more suitable choice; the aluminium-iron-manganese strengthening gives high static-load capacity at low to moderate sliding speed.

3. Why this material is used

The selection is application-driven:

• High static load at low to moderate speed — the alloy’s strength and hardness support heavy, slowly moving or pivoting joints.
• Shock and dirt loads — the ductile bronze body tolerates impact and contaminated conditions better than brittle or close-clearance alternatives.
• Corrosion resistance — suitable for atmospheric and many industrial-media environments; aluminium-bronze grades are preferred for seawater.
• Simple, low-cost design — plain bearings need no cages or rolling elements and are straightforward to fit.

4. Material technical data

Basis column: Standard = requirement of the cited EN/ISO/DIN document (minimum or limit); Typical = manufacturer-published indicative value, not a specified minimum.

4.1 Chemical composition (EN 1982 / DIN 2.0598, cast)

4.2 Mechanical and physical properties (cast)

4.3 Bearing performance — maintenance type (data-sheet indicative)

N/mm² equals MPa. The maximum PV value is the product of specific load (P) and sliding speed (V); exceeding it raises contact temperature and accelerates wear. Performance limits apply to the lubricated condition and depend on shaft, lubrication and duty cycle.

5. Forms and customization

• Cylindrical bushing
• Flanged bushing
• Thrust washer
• Strip / plate

Parts are manufactured to order; stock items are generally not held. All special dimensions are available. The same base alloy is also offered in other bronze grades on request.

6. Application part matrix (应用部位矩阵)

This matrix maps each application to the bearing part (部位) it serves, the operating condition, and the recommended CuZn25Al5 configuration. Use it together with the selection guide in Section 7.

7. Quick selection decision guide

8. Comparison with standard bronze bearing alloys

Values are manufacturer-published indicative data (Typical) for cast grades. They are screening values, not specification minima; use the lower bound for preliminary selection and confirm against the supplier lot report.

CuZn25Al5 shows the higher static-load and hardness figures in this set and a low elongation, consistent with its role in heavy, slow, shock-loaded joints. Supplier-specific proprietary grades (cited in some comparison sheets) are omitted here; they are not part of the open standard family.

9. Mounting and maintenance highlights

9.1 Tolerances and mating parts

Shaft: hardened and ground where possible; hardness at least 100 HB above the bearing; surface roughness ≤ Rz 6.3. A smoother shaft improves the lubricant film and wear life.

9.2 Mounting steps

• Housing bore: installation chamfer approx. 1.5 mm × 15° to 45°.
• Shaft: installation chamfer 5 mm × 15°, edges rounded.
• Use a suitable fitting mandrel; grease the outer surface if needed during press-fit.
• For flanged bushes, provide a flange seating chamfer (1.0 × 45°, larger sizes 1.5–2 × 45°) so the flange seats flat.

9.3 Lubrication

• Oil: preferred for higher speed and load; additives such as molybdenum disulphide or graphite can improve film adhesion.
• Grease: used for low speed, oscillation and shock; use plain-bearing greases. Solid additives above 2 % can cause premature wear; do not use molybdenum-disulphide grease on plastic bearings.
• Dry (graphite / MoS₂): solid-lubricant inserts let the graphite variant run maintenance-free; used for high temperature or one-time lubrication and emergency running.

9.4 Running-in and replacement

During running-in the lubricant (or dry layer) transfers to the mating surface and fills the roughness, lowering the friction coefficient. Inspect for scoring, excessive clearance growth, discoloration from overheating, or loss of lubrication path. Replace when clearance, noise or temperature exceed the design limit for the arrangement.

10. Engineering checklist

• Required Confirm load type: static ≤ 200 N/mm², dynamic ≤ 150 N/mm² (maintenance type).
• Required Confirm sliding speed ≤ 10 m/s and PV ≤ 1.8 N/mm² × m/s; de-rate for continuous duty.
• Required Verify temperature range −40 to +300 °C against lubricant limit.
• Required Specify housing H7, bushing inner E7, resulting s6/r6; set shaft tolerance (f7 per data sheet / e7–g7 per ISO 4379).
• Required Shaft hardened & ground, Δhardness ≥ 100 HB, roughness ≤ Rz 6.3.
• Add lubrication grooves/holes for contaminated or infrequent-service conditions.
• For dynamic/vibration duty, evaluate tin bronze (CuSn12) instead.
• For seawater, evaluate aluminium bronze (CuAl10Ni).
• Request EN 10204 inspection document (3.1 recommended) and verify against the lot.

11. Frequently asked questions

Which standard covers turned bronze sliding bearings?

Turned (solid, machined) bronze plain bearing bushes are covered by DIN 1850 and the international standard ISO 4379:2018. These standards define dimensions, tolerances and the material basis (cast copper alloys to ISO 4382-1 / wrought copper alloys to ISO 4382-2).

What are the load and speed limits of CuZn25Al5 turned bronze bearings?

For the maintenance-type bearing the data sheet gives a maximum static load of 200 N/mm², a maximum dynamic load of 150 N/mm², a maximum sliding speed of 10 m/s, a friction coefficient of 0.09 to 0.15 under boundary lubrication, and a maximum PV value of 1.8 N/mm² × m/s. The usable temperature range is −40 to +300 °C. Values are indicative and should be confirmed against the supplier test report for the actual lot.

What shaft and housing tolerances are used with these bearings?

The data sheet specifies a housing bore of H7, a bushing inner diameter machined to E7 that closes to s6 for diameters up to 120 mm and r6 above 120 mm after press-fitting, and a shaft tolerance of f7. ISO 4379:2018 recommends a shaft running fit of e7 to g7; both practices are in common use. The shaft should be hardened and ground, with a hardness at least 100 HB above the bearing and a roughness not exceeding Rz 6.3.

Is CuZn25Al5 suitable for maintenance-free operation?

The base turned-bronze version requires external oil or grease lubrication. A graphite-plugged variant of the same base alloy can run without ongoing external lubrication; for that variant the data sheet lists a reduced maximum static load of 150 N/mm² and a maximum dynamic load of 100 N/mm². Selection depends on the lubrication concept of the machine.

12. Appendix — sources, terminology, divergences and scope limits

12.1 Inspection documents (EN 10204)

These are supplier quality documents; none is a sector approval and none is an airworthiness release.

Material property data presented here is provided as a data source for engineering evaluation only and does not constitute an airworthiness finding, a certification basis, or any other certification conclusion.

13. Disclaimer

The data in this document is indicative and compiled from standards, foundry datasheets and a supplier comparison sheet. It is provided as a data source for engineering evaluation only. Actual values depend on temper, casting method, section size, lubrication, duty cycle and mating parts. No warranty of fitness for a particular purpose is given. Before design release and series production, verify the figures against the supplier’s test report (EN 10204 type 3.1) for the specific lot, and confirm tolerances and load limits with the part manufacturer. This document is not an airworthiness finding, certification basis, or any other certification conclusion.

Published by VIIPLUS SOLUTIONS. This material reference is provided for engineering evaluation only. Confirm all values against the supplier lot test report (EN 10204 type 3.1) and the part manufacturer before design release. This document is not an airworthiness finding, certification basis, or any other certification conclusion.