iglidur® K - material data

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

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 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).
 

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

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.