Solid bushes CAROBRONZE®

• Material
• Application fields
• Application reference
• Construction

Our bearing-materials:

We produce plain-bearings from all conventional Cu-alloys. Following you find an overview of the most important materials.

• Carobronze (CuSn8P)
• further bearing-materials

Carobronze®

Plain-bearings of Carobronze® show particularly following properties:

• high static and dynamic load
• excellent antifriction properties
• high wear-resistance

Alloy composition of CAROBRONZE®

Reference analysis : Sn: ca.8,5 % P: ca. 0,3 % Cu: residue
The admissible impurities are lower by a power of 10 than the values specified for CuSn8 and CuSn8P in DIN 17662 or DIN ISO 4382 part 2 respectively. The excellent antifriction properties of Carobronze® are not only due to the high purity but also to the alloy composition (high phosphorus and tin content) and the production procedure. The combination of all these features result in the advantage of Carobronze® over similar bearing materials which have the same material designation in DIN or DIN ISO.
Carobronze® represents the highest quality CuSn8P Bronze.

Mechanical and physical properties of Carobronze® (reference values)

A survey of further bearing materials:

Mechanical and physical properties (reference values)

Application fields for plain bearings are in particular:

• general mechanical engineering
• piston pumps and compressors
• construction- and agricultural- machines
• hydraulics and pneumatics
• motor- and gear- engineering
• vehicle- and waggon-construction
• mining machines
• printing machines and machine tools
• injection moulding machines
• packaging machines
• special purpose machines
• precision mechanics
• automotive industry

Application instructions

Because of the use of very wear-resistant base materials for the CARO Plain Bearings the hardness of the shaft material must also be specified in such a way that a hardness ratio of the base material to the mating material of 1 : 3 is guaranteed. Hard chrome plated and also hard nickel plated surfaces are well suited to use as mating surfaces and besides the desired hardness also provide additional corrosion protection. The plating thickness should amount to approximately 30 to 50 µm and the hardness should reach min.56 HRC.

Particularly for the highly loaded CARO Plain Bearings the surface quality of the shafts is critical when considering the coefficient of friction and the magnitude of the wear to be expected. Therefore, in most cases Rz roughness values of < 3 µm are required and, in general, the lower the Rz value, the lower the resulting coefficient of friction.

The coefficients of friction of plain bearings depend on a number of parameters. These are for example the surface qualities of the friction pairing, the temperature, the surface pressure and above all type and quantity of the existing lubricant. Generally it is true that the arising coefficient of friction, just as the admissible surface pressure, is not a material parameter but a system parameter which falls with increasing surface pressure after the running-in phase and rises within creasing temperature, higher speed and higher Rz roughness values.

For grease-lubricated plain bearings it is recommended not to use for a calculation coefficients of friction below 0.1. In the case of hydrodynamic running, oil-lubricated plain bearings coefficients of friction below 0.01 are to be expected.