iglidur® H4 - Material data

Materials table

Genera l features Unit iglidur® H4 test method
Density g/cm³ 1,79
Colour Brown
Max. humidity absorption at 23°C/50% R. H. % weight 0,1 DIN 53495
Max. water absorption % weight 0,2
Coefficient of surface friction, dynamic, against steel μ 0,08-0,25
pv value, max. (dry) MPa x m/s 0,7

Mechanical properties
Bending E-module MPa 7.500 DIN 53457
Tensile strength at +20 °C MPa 120 DIN 53452
Compressive strength at 20°C MPa 50
Maximum recommended surface pressure (20° C) MPa 65
Shore D-hardness 80 DIN 53505

Physical and thermal properties
Max. long term application temperature °C +200
Max. short term application temperature °C +240
Minimum application temperature °C -40
thermal / heat conductivity W/m x K 0,24 ASTM C 177
Coefficient of thermal expansion (at 23° C) K–1 x 10–5 5 DIN 53752

Electrical properties
Specific forward resistance Ωcm > 1013 DIN IEC 93
surface resistance Ω > 1012 DIN 53482
1) Without additional load; no gliding movement; relaxation not excluded.
'Table 01: Material Data
Fig. 01: Permissible pv values for iglidur® H4 bearings with a wall thickness of 1 mm


Figure 01: Permitted PV values for iglidur® H4 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® H4 bearings stand for high carrying capacity, good abrasion resistance and good temperature resistance, besides the obvious economic factors. Temperatures up to +200°C, permitted surface pressure of up to 65 MPa and excellent chemical resistance are just some of the essential attributes. Solid lubricants lower the coefficient of friction and support the wear resistance, which was essentially improved compared to the likewise cost-efficient iglidur® H2 bearings. iglidur® H4 bearings are self-lubricating and suitable for all motions.
Figure 02: Maximum recommended surface pressure dependent on the temperature (65 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® H4 bearings decreases. Fig. 02 clarifies this connection. With the long-term permitted application temperature of +200°C, the permitted surface pressure still amounts to 7 MPa.
 
Figure 03 shows the elastic deformation of iglidur® H4 with radial loads.

Maximum surface speed

m/s Rotary oscillating Linear
Constant 1 0,7 1
Short-term 1,5 1,1 2
Table 02: Maximum surface speeds

Permitted surface speeds

In contrast to the similarly cost-efficient iglidur® H2 bearings, the iglidur® H4 has an essentially favorable coefficient of friction. This accounts for the higher permitted surface speeds that can be attained with these bearings. In the dry operation, long-term speeds of
1 m/s are possible. The speeds stated in Table 02 are limit values for the lowest bearing loads. With higher loads, the permitted speed drops with the extent of the load due to the limitations by the p x v value.
Surface speed
p x v value and lubrication
iglidur® H4 Operating temperature
Lower - 40 °C
Upper, long-term + 200 °C
Upper, short-term + 240 °C
Secure axially in addition + 110 °C
Table 03: Temperature limits for iglidur® H4

Temperatures

iglidur® H4 is a temperature-resistant material. As a result, iglidur® H4 bearings can be used in applications in which bearings are subjected to a drying process without further load. With increasing temperatures, the compressive strength of iglidur® H4 bearings however decreases. The additional frictional heat in the bearing system must be taken into account. An additional securing is recommended at temperatures higher than +110°C.
Temperatures, coefficient of thermal expansion
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 of iglidur® H4 bearings is very low (Fig. 04 and 05). However it must be noted that an extremely coarse gliding partner increases the friction.
iglidur® H4 Dry Grease Oil Water
Coefficients of friction µ 0,08 - 0,25 0,09 0,04 0,04

Table 04: Coefficients of friction for iglidur® H4 against steel (Ra = 1 μm, 50 HRC)
Coefficients of friction
Wear resistance
Wear, rotating application with Fig. 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

Particularly given the high number of usable shaft materials, the iglidur® H4 is the economical alternative to many other high-temperature bearings. The important thing is however the selection of the suitable shaft material. It cannot be generally stated that iglidur® H4 is better suited for hard or soft shafts. Tests have however shown that pivoting motions yield better wear data. In rotating applications, the wear increases markedly from 10 MPa.
Shaft materials
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 = rotating
B = oscillating
Medium Resistance
Alcohols +
Hydrocarbons +
Greases, oils without additives +
Fuels +
Diluted acids + to 0
Strong acids + to -
Diluted bases +
Strong bases +
+ resistant      0 limited resistance      - not resistant
All specifications at room temperature[+20 °C]
Table 05: Chemical resistance of the iglidur® bearings H4


Electrical properties

Specific forward resistance > 1013 Ωcm
Surface resistance > 1012 Ω

Chemical resistance

iglidur® H4 bearings have a good resistance against chemicals. They are resistant to most lubricants.
The iglidur® H4 is not affected by most weak organic and inorganic acids.

Radioactive rays

iglidur® H4 withstands both the neutron and gamma particle radiations without noticeable loss of its excellent mechanical properties.
iglidur® H4 bearings are radiation resistant up to a radiation intensity of 2 x 102 Gy.

UV-resistant

iglidur® H4 bearings alter under the influence of UV rays and other climatic influences. The surface becomes coarser, and the compressive strength declines. Therefore the use of iglidur® H4 in applications directly exposed to climatic conditions should be tested.

Vacuum

The low water elements degas in the vacuum. The use in vacuum is possible.

Electrical properties

iglidur® H4 bearings are electrically insulating.
Max. humidity absorption
by +23 °C/50 % r. F. 0,1 weight-%
Max. water absorption 0,2 weight-%

Table 06: Moisture absorption of iglidur® H4
Effect of moisture absorption on plain bearings Diagram 10: Effect of moisture absorption
 
X = Moisture absorption [weight %]
Y = Reduction of inside diameter [%]
The humidity absorption of iglidur® H4 bearings is about 0.1% in standard climatic conditions. The saturation limit in water is 0,2 %. iglidur® H4 is therefore the ideal material for wet areas.
Diameter
d1 [mm]		 Shaft h9
[mm]		 iglidur® H4
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® H4 bearings according to ISO 3547-1 after the press-fit.

Installation tolerances

iglidur® H4 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 F10 tolerance. In certain dimensions the tolerance in dependence on the wall thickness deviates from this (See delivery program )