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iglidur® A290 - Material data

Materials table

General features Unit iglidur® A290 test method
Density g/cm³ 1,41
Colour white
Max. humidity absorption at 23°C/50% R. H. % weight 1,7 DIN 53495
Max. water absorption % weight 7,3
Coefficient of surface friction, dynamic, against steel µ 0,13 - 0,40
PV values max. (dry) MPa x m/s 0,23

Mechanical properties
Bending E-module MPa 8.800 DIN 53457
Tensile strength at +20 °C MPa 250 DIN 53452
compressive strength MPa 91
Maximum recommended surface pressure (20° C) MPa 70
Shore D hardness 88 DIN 53505

Physical and thermal properties
Max. long term application temperature °C +140
Max. short term application temperature °C +180
Lower application temperature °C -40
Heat conductivity [W/m x K] 0,24 ASTM C 177
coefficient of thermal expansion [K-1 x 10-5] 7 DIN 53752

Electrical properties
Specific forward resistance Ωcm > 1011 DIN IEC 93
Surface resistance Ω > 1011 DIN 53482
'Table 01: Material Data



 

Fig. 01: Permitted PV values for iglidur® A290 plain bearings with 1 mm wall thickness in dry-running operation against a steel shaft, at +20°C, installed in a steel housing
 
X = Surface speed [m/s]
Y = Load [MPa]

iglidur® 290 bearings was developed for use in the food industry. Compared to the bearings made of iglidur® A200, the tribological properties could be significantly improved.


Figure 02: Maximum recommended surface pressure dependent on the temperature (70 MPa to +20 °C)

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

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

Mechanical properties

Maximum recommended surface pressure represents a mechanical material parameter. Tribological conclusions cannot be drawn from it. With increasing temperatures, the compressive strength of iglidur® A290 plain bearings decreases. Fig. 02 clarifies this connection.
 
Under this load, the deformation is only about 2.5% at room temperature. A plastic deformation can be negligible up to this load. It is however also dependent on the period of exposure. Figure 03 shows the elastic deformation of iglidur® A290 with radial loads.


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

Table 02: Maximum surface speeds

Permitted surface speeds

iglidur® A290 is suitable for low surface speeds. Due to the relatively high friction particularly in the low load range, the bearings made of iglidur® A290 heat more strongly than other bearings. With higher speeds, the friction also increases.


iglidur® A290 Operating temperature
Lower - 40 °C
Upper, long-term + 140 °C
Upper, short-term + 180 °C
Secure axially in addition +110 °C
Table 03: Temperature limits for iglidur® A290

Temperatures

With increasing temperatures, the compressive strength of iglidur® A290 plain bearings decreases. Fig. 02 clarifies this connection. 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 120°C temperature onwards. An additional securing is recommended at temperatures higher than +110°C.


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

Friction and wear

The coefficient of friction alters like the wear resistance with increasing loadand surface speed (Fig. 04 and 05).

iglidur® A290 Dry Grease Oil Water
Coefficients of friction µ 0,13 - 0,40 0,09 0,04 0,04

Table 04: Coefficients of friction for iglidur® A290 against steel (Ra = 1 μm, 50 HRC)


Fig. 06: Wear, rotating application with various Figure 06: Wear, rotating application with different shaft materials, p = 1 MPa, v = 0.3 m/s
 
X = shaft materials
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

Figures 06 and 07 show an excerpt of the results of tests with different shaft materials conducted with bearings made of iglidur® A290. Compared to iglidur® A200, the improved tribological properties of iglidur® A290 are also reflected in the coefficients of wear. At low loads, the differences in the wear resistance of the combinations of iglidur® A290 with different shaft materials are very distinct.

Fig. 07: Wear in oscillating and rotating applications Fig. 07: Wear in oscillating and rotating applications with various shaft materials, p = 2 MPa
 
Y = wear [μm/km]
 
A= Cf53
B= hard chrome-plated
C= V2A
D= St37
 
Pink = rotating
Blue = oscillating

Medium Resistance
Alcohols + to 0
Hydrocarbons +
Greases, oils without additives +
Fuels +
Diluted acids 0 to -
Strong acids -
Diluted bases +
Strong bases + to 0
+ resistant      0 limited resistance      - not resistant
All specifications at room temperature[20 °C]
Table 05: Chemical resistance of the iglidur® bearings A290


Electrical properties

Specific forward resistance > 1011 Ωcm
Surface resistance > 1011 Ω

Chemical resistance

iglidur® A290 bearings have a good resistance against chemicals. They are resistant to most lubricants. iglidur® A290 is not affected by most weak organic and inorganic acids.
 

Radioactive rays

iglidur® A290 bearings are radiation resistant up to a radioactive intensity of 3 x 10² Gy.

UV-resistant

iglidur® A290 bearings are resistant to UV radiation, but the tribological properties deteriorate.

Vacuum

The iglidur® A290 bearings can be used in vacuum only restrictedly due to the high humidity absorption.

Electrical properties

iglidur® A290 bearings are electrically insulating.


Maximum moisture absorption
by +23 °C/50 % r. F. 1,7 weight-%
Max. water absorption 7,3 weight-%
Table 06: humidity absorption of iglidur® A290

Effect of moisture absorption on plain bearings Diagram 10: Effect of moisture absorption
 
X = Moisture absorption [weight %]
Y = Reduction of inside diameter [%]

Moisture absorption

The humidity absorption of iglidur® 200 bearings amounts to about 1,7% in standard climatic conditions. The saturation point in water at 7.3% is a disadvantage, which must be accounted for by all means in humid and wet area applications.


Diameter
d1 [mm]
Shaft h9
[mm]
iglidur® A290
D11 [mm]
Housing H7
[mm]
Up to 3 0 - 0,025 +0,020 +0,080 0 +0,010
> 3 to 6 0 - 0,030 +0,030 +0,105 0 +0,012
> 6 to 10 0 - 0,036 +0,040 +0,130 0 +0,015
> 10 to 18 0 - 0,043 +0,050 +0,160 0 +0,018
> 18 to 30 0 - 0,052 +0,065 +0,195 0 +0,021
> 30 to 50 0 - 0,062 +0,080 +0,240 0 +0,025
> 50 to 80 0 - 0,074 +0,100 +0,290 0 +0,030

Table 07: Important tolerances for iglidur® A290 bearings according to ISO 3547-1 after the press-in.

Installation tolerances

iglidur® A290 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 H7, the inner diameter of the bearing automatically adjusts to the D11 tolerance.