iglidur® X6 - material data

With respect to its general mechanical and thermal properties, iglidur® X6 is directly comparable to our high-temperature classic, iglidur® X, and may even provide advantages, such as its wear behavior.

Figure 2.2: Maximum recommended surface pressure dependent on the temperature (150 MPa at 20°C)

Figure 2.3: Deformation under load and temperatures

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® X6 plain bearings decreases. Fig. 02 clarifies this connection.

Figure 2.3 shows the elastic deformation of iglidur® X6 with radial loads. At a surface pressure of 100 MPa, the deformation is less than 2%. A potential plastic deformation depends, among other things, on the length of exposure.

m/s	Rotary	oscillating	Linear
Constant	1,5	1,1	5
Short-term	3,5	2,5	10

Table 2.2: Maximum surface speeds

Permitted surface speeds

iglidur® X6 is also intended for higher speeds due to its high temperature resistance and good thermal conductivity. 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® X6	Operating temperature
Lower	–100°C
Upper, long-term	+250 °C
Upper, short-term	+315 °C

Table 2.3: Temperature limits for iglidur® X6

Temperatures

The ambient temperatures influence the properties of bearings to a high degree. In terms of temperature resistance, iglidur® X6 takes a top position among iglidur® materials. In many tests, a six times higher wear resistance than the established "high-temperature specialist" iglidur® X was determined. iglidur® X6 bearings require additional axial securing only above +165°C temperatures.

Figure 2.4: Coefficients of friction dependent on the surface speed, p = 0,75 MPa

Figure 2.5: Coefficients of friction dependent on the load, v = 0,01 m/s

Friction and wear

Just like the wear resistance, the coefficient of friction µ, friction coefficient in short, also alters with the load. The friction coefficient of iglidur® X6 falls with the load and is more or less constant from about 30 MPa. The friction coefficient drops significantly also with the speed (see Figures. 2.4 and 2.5)

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 shaft material. Too smooth shafts increase the friction coefficient and the wear of the bearing at the same time. The best case for iglidur® X6 is a bottom surface with an average roughness of Ra = 0.4-0.7 μm. Fig. 06 shows the results of tests of different shaft materials with plain bearings made of iglidur® X6. The best performance is achieved with the shaft materials machining steel and bright steel 1.0037. For higher load cases we recommend tougher steels. Unhardened steel shafts may be subject to wear through the bearing at pressures of over 2 MPa. According to the wear database, iglidur® X6 is more suitable for rotary than swivel motion (Fig. 07). If the shaft material you are planning to use is not listed in these test results, please contact us.

iglidur® X6	Dry	Grease	Oil	Water
Coefficients of friction μ	0,09–0,21	0,09	0,04	0,04

Table 2.4: Coefficients of friction for iglidur® X6 against steel (Ra = 1 µm, 50 HRC)

Medium	Resistance at 20°C
Alcohols	+
Hydrocarbons	+
Fats, oils, without additives	+
Fuels	+
Diluted acids	+
Strong acids	+
Diluted bases	+
Strong bases	+

+ resistant      0 partially resistant      - non-resistant
Table 2.5: Chemical resistance of iglidur® X6

Electrical properties

Specific forward resistance	< 105 Ωcm
Surface resistance	< 103 Ω

Table 2.6: Electrical properties of iglidur® X6

chemical resistance

iglidur® X6 bearings have almost universal chemical resistance. They are affected only by concentrated nitric acid and sulfuric acid. The low humidity absorption allows them to be used in wet or humid environment. The bearings made of iglidur® X6 are resistant to common cleaning agents used in the food industry. The humidity absorption of iglidur® X6 bearings amounts to about 0,3 % in standard climatic conditions. The saturation limit in water is 1,3 %. These values are so low that an expansion due to moisture absorption needs to be considered only in extreme cases.

Radioactive rays

Resistant up to a radiation intensity of 2 x 10⁵ Gy

UV-resistant

limited resistance against UV rays

Vacuum

The iglidur® X6 bearings can also be used almost unrestrictedly in vacuum. An outgassing takes place only to a very minor degree.

Maximum moisture absorption
at +23 °C/50 % r.F.	0,1 weight-%
Max. water absorption	0,5 weight-%

Table 06: Moisture absorption of iglidur® X6

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

humidity absorption / moisture absorption

The moisture absorption of iglidur® X6 plain bearings amounts to about 0.1% in standard climatic conditions. The saturation limit in water is 0,5 %. These values are so low that a moisture expansion needs to be considered only in extreme cases.

Important tolerances for iglidur® X bearings according to ISO 3547-1 after the press-in

Diameter d1 [mm]	Shaft h9 [mm]	iglidur® X6 F10 [mm]	Housing H7 [mm]
Up to 3	0 - 0,025	+0,006 +0,046	0 +0,010
> 3 to 6	0 - 0,030	+0,010 +0,058	0 +0,012
> 6 to 10	0 - 0,036	+0,013 +0,071	0 +0,015
> 10 to 18	0 - 0,043	+0,016 +0,086	0 +0,018
> 18 to 30	0 - 0,052	+0,020 +0,104	0 +0,021
> 30 to 50	0 - 0,062	+0,025 +0,125	0 +0,025
> 50 to 80	0 - 0,074	+0,030 +0,150	0 +0,030

Table 07: Important tolerances for iglidur® X6 bearings according to ISO 3547-1 after the press-fit.

Installation tolerances

iglidur® X6 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.