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iglidur® H4 - Material data

Material table

General specification

Unit

iglidur® H4

Test method

density

g/cm³

1,79

Colour

brown

max. Moisture absorption at 23°C/50% room humidity.

% by weight

0,1

DIN 53495

max. total moisture absorption

wt.-%

0,2

Sliding friction coefficient, dynamic, against steel

μ

0,08-0,25

pv value, max. (dry)

MPa x m/s

0,7

Mechanical specification

flexural modulus

MPa

7.500

DIN 53457

flexural 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 specification

Upper long-term application temperature

°C

+200

Upper short-term application temperature

°C

+240

Lower application temperature

°C

-40

thermal 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 specification

Volume resistivity

Ωcm

> 1013

DIN IEC 93

surface resistance

Ω

> 1012

DIN 53482

  1. Without additional load; no sliding movement; relaxation not excluded

Table 01: Material data

diagram. 01: Permissible pv value for iglidur® H4 plain bearings with 1 mm wall thickness
diagram. 01: Permissible pv value for iglidur® H4 plain bearings with 1 mm wall thickness

diagram. 01: Permissible pv value for iglidur® H4 plain 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 load capacity, good abrasion resistance and good temperature resistance when economic aspects are also a priority. Temperatures up to +200 °C, permissible surface pressure up to 65 MPa and very good chemical resistance are just some of the key attributes. Solid lubricants lower the coefficient of friction and support the wear resistance, which has been significantly improved compared to the likewise very cost-effective iglidur® H2 bearings. iglidur® H4 bearings are self-lubricating and suitable for all movements.

Diagram 02: Maximum recommended surface pressure as a function of temperature (65MPa at +20°C)

X = temperature [°C]
Y = load [MPa]

Mechanical specification
The maximum recommended surface pressure is a mechanical material parameter. Conclusions on the tribology cannot be drawn from this. The compressive strength of iglidur® H4 bearings decreases with increasing temperatures. diagram.02 illustrates this correlation. At the long-term permissible application temperature of +200 °C, the permissible surface pressure is still 7 MPa.

Diagram 03: Deformation under pressure and temperature

X = load [MPa]
Y = Deformation [%]

diagram. 03 shows the elastic deformation of iglidur® H4 under radial load.

Maximum surface speed

m/s

rotating

oscillating

linear

continuous

1

0,7

1

short-term

1,5

1,1

2

Table 02: Maximum surface speed

Permissible sliding speeds
Compared to the cost-effective iglidur® H2 plain bearings, iglidur® H4 has a much more favourable friction coefficient. This is the reason for the higher permissible sliding speeds that can be achieved with these bearings.
1 m/s. The speeds given in Table 02 are limit values for the lowest bearing loads. At higher loads, the permissible speed decreases with the load due to the limitations of thepv value.

iglidur® H4

Application temperature

below

- 40 °C

upper, long-term

+ 200 °C

upper, short-term

+ 240 °C

additional axial protection from

+ 110 °C

Table 03: Temperature limits for iglidur® H4

Temperatures
iglidur® H4 is a temperature-resistant material, which is why iglidur® H4 plain bearings can be used in applications in which bearings are subjected to a drying process without further load. However, the compressive strength ofiglidur® H4 bearings decreases with increasing temperatures. The additional frictional heat in the bearing system must be taken into account. Additional protection is required at temperatures higher than +110 °C.

Diagram 04: Coefficient of friction as a function of the surface speed, p = 0.75MPa

X = surface speed [m/s]
Y = coefficient of friction μ

Friction and wear
The coefficient of friction of iglidur® H4 plain bearings is very low (diagrams 04 and 05). However, it must be noted that a rough sliding partner increases the friction.

Diagram 05: Coefficient of friction as a function of the pressure, v = 0.01m/s

X = load [MPa]
Y = coefficient of friction μ

iglidur® H4

dry

Grease

oil

water

coefficient of friction µ

0,08 - 0,25

0,09

0,04

0,04

Table 04: coefficient of friction for iglidur® H4 against steel (Ra = 1 μm, 50 HRC)

Wear, rotating application with

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

X = Shaft material
Y = wear [μm/km]

A = aluminium, hard anodised
B = free cutting steel
C = Cf53
D = Cf53, hard chrome-plated
E = HR carbon steel
F = 304 SS
G = high grade steel

Shaft materials
iglidur® H4 is the economical alternative to many other high-temperature bearings precisely because of the large number of shaft materials that can be used. However, it is important to select the suitable shaft material. It cannot generally be said that iglidur® H4 is better suited for hard or soft shafts. Tests have shown that swivelling movements lead to better wear data; in rotating operation, wear increases significantly from 10 MPa.

Shaft materials
Wear for oscillating and rotating

diagram. 07: Wear in 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, not additivated

fuels

Diluted acids

+ to 0

strong acids

+ to -

Dilute bases

strong bases

+ resistant 0 conditionally resistant - not resistant
All data at room temperature [+20 °C]
Table 05: chemical resistance of iglidur® H4

Chemical resistance
iglidur® H4 plain bearings have good resistance to chemicals. They are resistant to most lubricants.
Most weak organic and inorganic acids do not attack iglidur® H4.

**
Electrical specification

Volume resistivity

> 1013 Ωcm

surface resistance

> 1012 Ω

Radioactive radiation
iglidur® H4 resists both neutron and gamma particle radiation without any noticeable loss of its excellent mechanical specification.
Bearings made of iglidur® H4 are radiation-resistant up to a radiation intensity of 2 - 102 Gy.

max. Moisture absorption

at +23 °C/50 % room humidity.

0.1 % by weight

max. total moisture absorption

0.2 % by weight

Table 06: Moisture absorption of iglidur® H4

The moisture absorption of iglidur® H4 bearings is less than 0.1 % in a normal climate. The saturation limit in water is 0.2 %. iglidur® H4 is therefore the ideal material for wet environments.

Influence of moisture absorption

diagram. 10: Influence of moisture absorption

X = Moisture absorption [Gew.-%]
Y = Reduction inside ø [%]

Diameter****d1 [mm]

shaft h9**[mm]**

iglidur® H4****F10 [mm]

housing H7**[mm]**

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 plain bearings according to ISO 3547-1 after press-fitting

Installation tolerances
iglidur® H4 plain bearings are standard bearings for shafts with tolerance (recommended minimum h9).

The bearings are designed to be pressed into anH7-toleranced mounting. After installation in a mounting with nominal dimensions, the inner diameter of the bearing with F10 tolerance is automatically adjusted; for certain dimensions, the tolerance deviates from this depending on the wall thickness (see product range).

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