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iglidur® K - material data

Material properties

Genera l features Unit iglidur® K test method
Density g/cm³ 1,52
Colour yellow-beige
Max. humidity absorption at 23°C/50% R. H. % weight 0,1 DIN 53495
Max. water absorption % weight 0,6
Coefficient of surface friction, dynamic, against steel µ 0,06 - 0,21
pv values (dry) MPa x m/s 0,30

Mechanical properties
Bending E-module MPa 3.500 DIN 53457
Tensile strength at +20 °C MPa 80 DIN 53452
compressive strength MPa 60
Maximum recommended surface pressure (20° C) MPa 50
Shore D-hardness 72 DIN 53505

Physical and thermal properties
Max. long term application temperature °C +170
Max. short term application temperature °C +240
Minimum application temperature °C -40
thermal / heat conductivity W/m x K 0,25 ASTM C 177
Coefficient of thermal expansion (at 23° C) K-1 x 10-5 3 DIN 53752

Electrical properties
Specific forward resistance Ωcm > 1012 DIN IEC 93
surface resistance Ω > 1012 DIN 53482
Table 01: Material properties





Figure 01: Permitted PV values for iglidur® K bearings with 1 mm wall thickness in dry operation against a steel shaft, at 20°C, installed in a steel housing.

X = Surface speed [m/s]
Y = Load [MPa]

iglidur® K is characterised by its good wear behaviour at low moisture absorption and good thermal and mechanical properties. This supports a very universal application spectrum.


Figure 02: Maximum recommended surface pressure according to the temperature (60 MPa at 20°C)

X = Temperature [°C]
Y = Load [MPa]
Figure 03: Deformation under load and temperatures Figure 03: Deformation under load and temperatures

X = Load [MPa]
Y = Deformation [m/s]

Mechanical properties

With increasing temperatures, the compressive strength of iglidur® K plain bearings decreases. Fig. 02 clarifies this connection. Maximum recommended surface pressure represents a mechanical material parameter. Tribological conclusions cannot be drawn from it.


 

 

 

 

 
Figure 03 shows the elastic deformation of iglidur® K with radial loads. Under the maximum recommended surface pressure of 50 MPa, the deformation amounts to less than 3%. A potential plastic deformation depends, among other things, on the length of exposure.


Maximum surface speed

m/s Rotary oscillating Linear
Constant 1 0,7 3
Short-term 2 1,4 4

Table 02: Maximum surface speeds

Permitted surface speeds

iglidur® K has been developed for low to medium surface speeds. The maximum values stated in Table 02 can be attained only with minor pressure loads. At the specified speeds, an increase in temperature up to the long-term permitted value can occur due to friction. In practice these limit values are not always reached due to interactions.


iglidur® K Application temperature
Lower -40°C
Upper, long-term +170 °C
Upper, short-term +240 °C
Secure axially in addition +70 °C
Table 03: Temperature limits

Temperatures

The temperatures prevailing in the bearing system also have an influence on the bearing wear. The wear increases with rising temperatures, and the influence is especially marked from 100°C temperature onwards. An additional securing is recommended at temperatures higher than +70°C.


iglidur® K Dry Grease Oil Water
Coefficients of friction µ 0,06-0,21 0,09 0,04 0,04

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

Friction and wear

Just like the wear resistance, the coefficient of friction µ also alters with the load (Fig. 04 and 05).

Figure 04: Coefficients of friction dependent on the surface speed, p = 0,75 MPa

X = Surface speed [m/s]
Y = Coefficient of friction μ
Figure 05: Coefficients of friction dependent on the load, v = 0,01 m/s

X = Load [MPa]
Y = Coefficient of friction μ

iglidur® K wear for different materials Figure 06: Wear, rotating application with different shaft materials, p = 1 MPa, v = 0,3 m/s
 
X = Shaft material
Y = Wear [μm/km]
 
A = Aluminum, hard-anodized
B = machining steel
C = Cf53
D = Cf53, hard chrome-plated
E = St37
F = V2A
G = X90

shaft materials

Friction and wear also depend to a high degree on the reverse partner. Very smooth shafts increase the coefficient of both friction and wear. A smoothed surface with an average surface finish Ra = 0.15–0.20 µm is best suited for iglidur® K. Figure 06 displays a summary of the results of tests with different shaft materials, which were conducted with iglidur® K plain bearings. In this connection it is important to note that with increasing loads, the recommended hardness of the shaft increases. The "soft" shafts tend rather to wear themselves and thus increase the wear of the entire system, if the loads exceed 2 MPa. The comparison of rotating and pivoting movements shows that the wear is virtually identical up to a load of 5 MPa. Higher the load, the greater is the difference (Fig. 07).
 

Wear in oscillating and rotating Fig. 07: Wear with oscillating and rotating applications with Cf53 as a function of the load
 
X = Load [MPa]
Y = Wear [μm/km]
 
A = rotary
B = oscillating

Medium Resistance
Alcohols + to 0
Hydrocarbons +
Fats, oils, without additives +
Fuels +
Diluted acids 0 to -
Strong acids -
Diluted bases +
Strong bases 0
+ resistant      0 partially resistant      - non-resistant All specifications at room temperature [+20°C]
Table 05: Chemical resistance of iglidur® K


Electrical properties

Specific forward resistance > 1012 Ωcm
Surface resistance > 1012 Ω

chemical resistance

iglidur® K bearings are resistant to diluted alkalis and very weak acids as well as to fuels and all kinds of lubricants. The low humidity absorption allows them to be used in wet or humid environment.

Radioactive rays

iglidur® K plain bearings are radiation resistant up to a radiation intensity of5 x 102 Gy.

UV-resistant

iglidur® K plain bearings change colour under the influence of UV radiation. However, the material properties do not change.

Vacuum

In vacuum, iglidur® K degases. The use in vacuum is possible only limitedly.

Electrical properties

Electrically insulating


Maximum moisture absorption
by +23 °C/50 % r. F. 0,1 Wt.-%
Max. water absorption 0,6 Wt.-%

Table 06: Moisture absorption

Influence of moisture absorption Fig. 08: Influence of moisture absorption
 
X = Moisture absorption [Wt-%]
Y = Reduction of the inner diameter [%]

humidity absorption / moisture absorption

The humidity absorption of iglidur® K bearings amounts to about 0.1 % in standard climatic conditions. The saturation limit in water is 0,6 %. These values are so low that a moisture expansion need to be considered only in extreme cases.


Diameter
d1 [mm]
Shaft
h9 [mm]
iglidur® K
E10 [mm]
Housing H7
[mm]
Up to 3 0 - 0,025 +0,014 +0,054 0 +0,010
> 3 bis 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 bis 180 0 - 0,100 +0,085 +0,245 0 +0,040

Table 07: Important tolerances iaw. ISO 3547-1 after press-fitting

Installation tolerances

iglidur® K bearings are standard bearings for shafts with h-tolerance (recommended minimum h9). The bearings are designed for press-fit in a housing with h7 tolerance. After the installation in a housing with nominal diameter, the inner diameter of the bearing automatically adjusts to the E10 tolerance. Compared to the installation tolerance, the inner diameter varies according to moisture absorption.