iglidur® A290 - Material data

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)

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.

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

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.