iglidur® K - Material data

Material properties

General specification

Unit

iglidur®® K

Test method

density

g/cm³

1,52

Colour

yellow-beige

max. Moisture absorption at 23°C/50% room humidity.

% by weight

0,1

DIN 53495

max. total moisture absorption

wt.-%

0,6

Sliding friction coefficient, dynamic, against steel

0,06 - 0,21

pv value, max. (dry)

MPa x m/s

0,30

Mechanical specification

flexural modulus

MPa

3.500

DIN 53457

flexural strength at 20°C

MPa

DIN 53452

Compressive strength

MPa

maximum recommended surface pressure (20°C)

MPa

Shore D hardness

DIN 53505

Physical and thermal specification

Upper long-term application temperature

°C

+170

Upper short-term application temperature

°C

+240

Lower application temperature

°C

-40

thermal conductivity

W/m x K

0,25

ASTM C 177

coefficient of thermal expansion (at 23°C)

K-1 x 10-5

DIN 53752

Electrical specification

Volume resistivity

Ωcm

> 1012

DIN IEC 93

surface resistance

> 1012

DIN 53482

Table 01: Material properties

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iglidur® K is characterised by good wear behaviour with low moisture absorption and good thermal and mechanical specifications. This makes the range of applications very universal.

Mechanical specification
The compressive strength of iglidur® K plain bearings decreases with increasing temperatures. diagram 02 illustrates this correlation. The maximum recommended surface pressure represents a mechanical material characteristic value; conclusions about the tribology cannot be drawn from this.

Diagram 03: Deformation under pressure and temperature

diagram. 03 shows the elastic deformation of iglidur® K under radial load. Under the maximum recommended surface pressure of 50 MPa, the deformation is less than 3 %. Possible plastic deformation depends, among other things, on the duration of the impact.

Maximum surface speed

m/s

rotating

oscillating

linear

continuous

0,7

short-term

1,4

Table 02: Maximum surface speed

Permissible sliding speeds
iglidur® K has been developed for low to medium sliding speeds. The maximum values specified in Table 02 can only be reached at low pressure loads. At the specified speeds, friction can lead to an increase up to the limit of the permanently permissible temperature; in practice, these limit values cannot always be achieved due to the interaction of different influences.

iglidur® K

Application temperature

below

-40°C

upper, long-term

+170 °C

upper, short-term

+240 °C

additional axial protection from

+70 °C

Table 03: Temperature limits

Temperatures
The temperatures prevailing in the bearing system also have an influence on bearing wear. Wear increases with rising temperatures, and the influence is particularly noticeable from a temperature of +100 °C. An additional fuse is required at temperatures higher than +70 °C.

iglidur® K

dry

Fat

oil

water

coefficient of friction µ

0,06-0,21

0,09

0,04

Table 04: coefficient of friction for iglidur® K against steel (Ra = 1 μm, 50 HRC)

Friction and wear
Like the wear resistance, the coefficient of friction μ also changes with the load (diagram. 04 and 05).

iglidur® K Wear with different materials

Shaft materials
Friction and wear are also highly dependent on the mating partner. Shafts that are too smooth increase both the coefficient of friction and the wear of the bearing. iglidur® K is best suited to a ground surface with an average surface finish Ra = 0.15-0.20 μm.diagram. 06 shows an extension of the results of tests with different shaft materials that were carried out with iglidur® K plain bearings. In this context, it is important to note that the recommended hardness of the shaft increases with increasing loads. The "soft" shafts tend to wear themselves and thus increase the wear of the overall system if the load exceeds 2 MPa. The comparison of rotating and swivelling movements shows that the wear is almost identical up to a load of 5 MPa. The higher the load, the greater the difference (diagram.07).

Shaft materials

Medium

Resistance

Alcohols

+ to 0

Hydrocarbons

Greases, oils, not additivated

fuels

Diluted acids

0 to -

strong acids

Dilute bases

strong bases

+ resistant 0 conditionally resistant - not resistantAll data at room temperature [+20 °C]
Table 05: chemical resistance of iglidur® K

Chemical resistance
iglidur® K plain bearings are resistant to diluted alkalis and very weak acids as well as fuels and all types of lubricants. The low moisture absorption also allows use in wet or damp environments.

**
Electrical specification

Volume resistivity

> 1012 Ωcm

surface resistance

> 1012 Ω

Radioactive radiation
Bearings made of iglidur® K are resistant to radiation up to a radiation intensity of 5 x 102 Gy.

Maximum moisture absorption

at +23 °C/50 % room humidity.

0.1 % by weight

max. total moisture absorption

0.6 % by weight

Table 06: Moisture absorption

Moisture absorption
The moisture absorption of iglidur® K bearings is about 0.1 % in a normal climate. The saturation limit in water is 0.6 %. These values are so low that consideration of swelling due to moisture absorption is only necessary in extreme cases.

Diameter****d1 [mm]

shaft h9**[mm]**

iglidur® K****E10 [mm]

housing H7**[mm]**

to 3

0 - 0,025

+0,014 +0,054

0 +0,010

> 3 to 6

0 - 0,030

+0,020 +0,068

0 +0,012

> 6 to 10

0 - 0,043

+0,025 +0,083

0 +0,015

> 10 to 18

0 - 0,043

+0,032 +0,102

0 +0,018

> 18 to 30

0 - 0,052

+0,040 +0,124

0 +0,021

> 30 to 50

0 - 0,062

+0,050 +0,150

0 +0,025

> 50 to 80

0 - 0,074

+0,060 +0,180

0 +0,030

> 80 to 120

0 - 0,087

+0,072 +0,212

0 +0,035

> 120 to 180

0 - 0,100

+0,085 +0,245

0 +0,040

Table 07: Important tolerances according to ISO 3547-1 after press-fitting

Installation tolerances
iglidur® K bearings are standard bearings for shafts with h-tolerance (at least h9 recommended). The bearings are designed to be pressed into an H7-toleranced mounting. After installation in a mounting with nominal dimensions, the inner diameter of the bearing with E10 tolerance adjusts itself. Compared to the installation tolerance, the inner diameter changes depending on the moisture absorption.