Application

Application of KS P147

KS P147 has been designed for maintenance-free use. This material offers specific advantages thanks to its improved corrosion resistance to salty atmospheres. It is therefore especially suited for windscreen wiper systems or applications in hinges (car doors, engine hoods, trunk decks).

Preferred areas of application

  • In aggressive media1)
  • Outside machines and systems1)
  • Maintenance-free operation in dry-running conditions where unleaded parts are required
  • Rotating or oscillating movements up to a speed of 0.8 m/s
  • Linear movements
  • Temperature range –200 °C to 280 °C

1)P147 satisfies the requirements of the salt spray test to DIN 50021

Hydrodynamic operation

Use in hydrodynamic conditions is possible without problems up to a sliding speed of 3 m/s. In continuous operation above 3 m/s, there is a risk of flow erosion or cavitation. Motorservice offers the calculation of hydrodynamic operating states as a service

Description

Brief description of the sliding material

P147 is an unleaded special sliding material with a high tribological performance.
It is designed for maintenance-free, dry-running applications, particularly in areas subject to increased corrosion. It may also be used in systems with liquid lubrication. The use of grease as a lubricant with P147 is only possible to a limited extent, and is not recommended

Properties of P147

  • Unleaded
  • Compliant with Directive 2011/65/EU (RoHS II)
  • Very low stick-slip tendency
  • Low wear
  • Good chemical resistance
  • Low friction value
  • No tendency to fuse with metal
  • Very low tendency to swell
  • Does not absorb water
  • Very good corrosion resistance

In a final step, plain bearings manufactured from P147 undergo special anti-corrosion treatment on the bearing back, face reliefs and striking faces.

  • Standard version: Tin
    Layer thickness: approx. 0.002 mm
  • Increased corrosion protection requirements (on request)
    Version: Zinc, transparent passivated
    Layer thickness: 0.008 mm to 0.012 mm
    Higher layer thickness available on request.

Bearing structure

Bearing structure of KS P147

Sliding elements in KS P147 consist of a steel back, a sintered-on, porous tin-bismuth-bronze coat and the solid lubricant PTFE with BaSO4 as filler.

The steel carrier material used is typically of grade DC04. Its hardness ranges from 100 to 180 HB.

The steel thickness is chosen as a function of the proposed application. Typical thicknesses are between 0.7 and 3.2 mm.

The contact surface is made up of nodular CuSn10Bi8 bronze. The bronze is sintered to exhibit a pore volume of about 30 %. The coat thickness is 0.2 – 0.35 mm. The pores are filled with a thermally treated solid lubricant which covers the bronze surface, acting as run-in coat. The run-in coat thickness is 0.005 – 0.030 mm.

Tribological system bearing/shaft in dry run

Besides load, sliding speed and ambient temperature as factors influencing wear, the shaft material also plays an important part in dry run mode. Depending on the shaft material, the expected service life of the plain bearing may substantially vary from the normal level. Also the surface roughness of the shaft also plays an important role. It should be in the range of Rz 1–3.

1 Running-in layer: PTFE matrix with bulking agent1)

  • Layer thickness [mm]: max. 0.03

2 Sliding layer: Tin-bronze

  • Layer thickness [mm]: 0.20–0.35
  • Pore volume [%]: approx. 30

3 Bearing back: Steel

  • Steel thickness [mm]: Variable
  • Steel hardness [HB]: 100–180
  • Material characteristics
    Characteristics, limit loadsUnitKS P209

    Permissible pv value

    MPa · m/s

    1.4

    Permitted specific bearing stress

    • Static
    • Concentrated load, circumferential load at sliding speed ≤ 0.010 m/s
    • Concentrated load, circumferential load at sliding speed ≤ 0.025 m/s
    • Concentrated load, circumferential load, increasing at a sliding speed of ≤ 0.050 m/s

     

    N/mm²
    N/mm²
    N/mm²
    N/mm²

     

    250
    140
    56
    28

    Permissible sliding speed v

    • Dry running at p ≤ 1.75 MPa

     

    m/s

     

    0.8

    Permissible temperature range

    °C

    -200 to +280

    Coefficient of thermal expansion, steel back

    k-1

    11 · 10-6

    Coefficient of thermal conductivity, steel back

    W · (m·k)-1

    40

  • Chemical composition of the solid lubricant

    Running-in layer

    Components

    % weight

    PTFE

    82

    BaSO4

    18

    Sliding layer

    Components

    % weight

    Sn

    9 bis 11

    Cu

    Remainder

    Material

    Material information

    Steel

    DC04

    DIN EN 10130

    DIN EN 10139

  • Lifetime factor of shaft materials (dry run)

    1: Steel shaft X 155 Cr V Mo 121 (base shaft), hardness 58 HRc
    2: Shaft of hard-anodized aluminum, hardness 450 HV
    3: Shaft of gray cast iron (GG 25)
    4: Steel shaft, nitrated, hardness 1000 HV, 0.2 mm deep

    Test conditions

    • Rotation
    • Point load
    • Sliding speed 0.42 m/s
    • Specific load 2 N/mm2
    • Shaft material cf. above diagram “lifetime factor of shaft materials”
    • Surface roughness (shaft) ~ Rz 1.5–2
    • Room temperature
    • Test duration 60 h
  • Comparison of wear behavior

    Test conditions

    • Rotation
    • Point load
    • Sliding speed 0.42 m/s
    • Specific load 2 N/mm2
    • Shaft material steel shaft X 155 Cr V Mo 121, hardness 58 HRc
    • Surface roughness (shaft) ~ Rz 1.5–2
    • Room temperature
    • Test duration 60 h

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Manufacture

Manufacture of the sliding material

The solid lubricant mass is produced in a specially adapted mixing process. In a parallel, continuous sintering operation, bronze powder is sintered onto the steel back as a sliding layer. This produces a sliding layer with a thickness from 0.2 mm to 0.35 mm and a pore volume of approx. 30%. Next, the cavities are filled with solid lubricant by means of impregnating rollers. This process step is controlled in such a way that a running-in layer of solid lubricant up to max. 0.03 mm thick is produced above the sliding layer. In further thermal treatments, the characteristic properties of the material system are adjusted, and the required thickness tolerances of the composite material are produced using controlled roller pairs.

Minor alterations of the contact surface color will not affect the performance of the plain bearing.