Plain bearings

ZFO-P© - sliding materials

ZFO-P© represents a protected steel plain bearing brand with excellent sliding-tribological properties under mixed-friction conditions.
The sliding material, a special Fe-C-N composite material underwent several heat treatments, is based on a fine-grained, micro-alloyed steel matrix with a high compression yield point.
The firmly embedded and finely dispersed hard materials are resistant to a wide range of abrasives. A low-maintenance operating mode – with savings regarding more expensive, environmentally compatible greases - is often possible.

Particular sustainability aspects: Download our publication "Maschinen und Technik"

ZFO-P bushings are a sustainable substitute for bronzes and brasses.
Due to its enormous consumption of resources in mining and production, copper alloys have a comparatively heavy “ecological impact”.
The toxic effect of copper-bearing materials compared to microorganisms (biocenosis) with Cu contents exceeding 60 % is of current importance. The sliding wear particles of bronze and brass bushings from building machinery and grab bearings are resulting in a serious impairment of our ecosystems. The increasing demand from the electromobility and the alternative power generation will lead to a further shortage with considerable price jumps of copper, tin and zinc.

Therefore, a dissipative use of the superior conductor material Cu in oscillatively operated friction bearings is no longer appropriate because of alternative steel-sliding materials from a business-management and economic point of view.


The plain bearings of the ZFO-P steel brand

  • have a high wear resistance to adhesion, abrasion and surface fatigue
  • are highly resistant to static and dynamic stress
  • have a low-friction, corrosion protective overlay with rhomb groove structure
  • are heat-resistant up to 500°C
  • need less lubricants than bronze and brass bushings etc.
  • are an ecological and cost-efficient replacement of Cu alloys


The geometric modification of the whole sliding surface with fine “smart” rhomb groove structures achieves a minimization of the friction coefficient. The proportion of the fluid friction is increased. The local tribological stress is considerably reduced so that the service life - with simultaneously smooth operating mode - increases. The smart technology is favourable if specific requirements on a minimum integral friction force are imposed combined with grease lubrication of sufficient viscosity.


Wrapped steel bushes, e. g., of spring steel or Cu alloy which, are joined in rough housing seats according to H9/H10/H11 can be substituted by this fully cylindrical designwith elastic adjustment to the housing bore. Thus, the high wear resistance of ZFO-P steel sliding materials can also be used in such cases of application in a cost-effective way – without changing the fitting accuracy.


This rust-proof version allows the use combined with the requirement on a high corrosion resistance, e. g., in seawater environments. Due to vacuum-supported heat treatments of appropriate steels and diffusion techniques, resistant structures against the specific application-oriented and specifically acting wear mechanisms are assembled.
Regarding geometrical aspects, different corrosion-proof cylindrical plain bearings and/or spherical plain bearings with defined hardness gradients from inner and outer ring can be manufactured to achieve an optimized hardness gradient.

Counter bodies in the tribological system with ZFO-P plain bearings

The axle/wave counter bodies should consist of induction hardened heat treatable steels or of case-hardened or carbonitrided steels.
Through-hardened axles made of tough rolled or cold work steels are also possible, if a hardness of 57-58 HRC can be achieved.
Martensitic chromium steels, in individual cases with nickel and/or molybdenum additions are suited as corrosion-proof axles. A chromium layer on surface hardened heat treatable steels is often sufficient.

Application areas

  • Bearings in joints of wheel loaders
  • Conveyor equipment for container stripping/undercarriages
  • Crane joints | jib bearings
  • Cylinder pivots
  • Bearings in shipbuilding
  • Lifting gear bearings | gripper joints
  • Excavator joints | jib bearings | mining equipment
  • Tractor joints | accessory equipment | spring suspensions | steering linkages
  • Replacement of various bronze bearings in joints of the steel, cement, aluminium industry
ZFO-P (application)ZFO-P (application)
ZFO-P (application)ZFO-P (application)
ZFO-PZFO-PsplitZFO-PZFO-P (application)ZFO-PsmartZFO-PsmartZFO-PsmartZFO-PniroZFO-P (application)