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iglidur® UW - material data

Material data table

General properties

Unit

iglidur® UW

Testing method

Density

g/cm³

1.52

Colour

black

Max. moisture absorption at +23°C/50% room humidity

% weight

0.2

DIN 53495

Max. water absorption3)

% weight

0.8

Coefficient of sliding friction, dynamic against steel

μ

0.15-0.35

pv value, max. (dry)

MPa x m/s

0.11

Mechanical properties

Flexural modulus

MPa

9,600

DIN 53457

Flexural strength at 20°C

MPa

90

DIN 53452

Compressive strength

MPa

70

Maximum recommended surface pressure (20°C)

MPa

40

Shore D hardness

78

DIN 53505

Physical and thermal properties

Max. long-term application temperature

°C

+90

Max. short-term application temperature

°C

+110

Min. application temperature

°C

-50

Thermal conductivity

W/m x K

0.60

ASTM C 177

Coefficient of thermal expansion (at 23°C)

K-1 x 10-5

6

DIN 53752

Electrical specifications2)

Specific transitional resistance

Ωcm

<105

DIN IEC 93

Surface resistance

Ω

<105

DIN 53482

  1. Under certain circumstances, the good conductivity of this plastic can favour the generation of corrosion on the metallic contact components.
  2. With regard to the application of the material in direct contact with water, it must be pointed out that all results were obtained under laboratory conditions using DI water (deionised water). We therefore recommend application-specific tests under real conditions of use.
    Table 01: Material data
Logarithmic graph with a falling red line on the X- and Y-axes.
Logarithmic graph with a falling red line on the X- and Y-axes.

Diagram 01: Permissible pv values for iglidur® UW plain bearing with a wall thickness of 1mm in dry operation against a steel shaft at +20°C, mounted in a steel housing

X = Surface speed [m/s]
Y = Load [MPa]

iglidur® UW was developed for underwater applications in which the maximum temperatures are significantly lower than +100°C. For application temperatures above this limit, the plain bearings made from iglidur® UW500 are available. Although iglidur® UW was developed for application in liquids, it is also suitable for dry operation. This is particularly important in applications that are used in both dry and wet operations, which is often encountered in practice. Unless specifically stated otherwise, the specifications of the bearings made from iglidur® UW described in this section apply to the dry operation.

Line chart with a falling curve from about 40 at X = 20 to 20 at X = 90.

Diagram. 02: Maximum recommended surface pressure as a function of temperature (50MPa at +20°C)

X = Temperature [°C]
Y = Load [MPa]

Mechanical specifications
The maximum recommended surface pressure represents mechanical material parameter. No conclusions regarding the tribological properties can be drawn from this. With increasing temperatures, the compressive strength of iglidur® UW plain bearings decreases. Picture 02 shows this relationship.

Graph with two lines: +60°C rises significantly more steeply than +23°C from X = 0 to 40.

Diagram 03: Deformation under pressure and temperature

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

Diagram 03 shows the elastic deformation of iglidur® UW at radial loads. At the maximum recommended surface pressure of 40MPa, the deformation is less than 1%.

m/s

Rotating

Oscillating

Linear

permanent

0.5

0.4

2

Short-term

1.5

1.1

3

Table 02: Maximum surface speed

Permissible surface speed
iglidur® UW is suitable for dry operation as well as in liquids and at higher speed. Due to hydrodynamic lubrication, which is possible underwater at high speeds, a surface speed far higher than 2m/s can be achieved.

The iglidur® UW plain bearings can be used in dry operation at a short-term speed of up to 1.5m/s.

iglidur® UW

Application temperature

Minimum

-50°C

Maximum, long-term

+90°C

Maximum, short-term

+110°C

In addition secure axially from

+80°C

Table 03: Temperature limits for iglidur® UW

Temperatures
As stated earlier, iglidur® UW plain bearings are required for use in the low-temperature range. As the liquid usually dissipates heat in underwater applications, the temperature of the liquid is of great importance. Temperatures of over +80°C require additional securing.

Graph with an almost constant characteristic curve: Y-value rises slightly from about 0.33 to 0.35 at X = 0.05 to 0.30.

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 surface finish of the shafts should not be too smooth so as to prevent a high adhesion effect and a related increase in the coefficient of friction. Please contact us for the specifications of shaft surface finish in underwater applications.

Graph with a falling curve: Y-value falls from about 0.5 at X = 0 to around 0.12 at X = 40.

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

X = Load [MPa]
Y = Coefficient of friction µ

iglidur® UW

dry

Greases

Oil

Water

Coefficient of friction µ

0.15 - 0.35

0.09

0.04

0.04

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

Bar chart with four categories A to D and two coloured data series.

Diagram 07: Wear in oscillating and rotating applications with Cf53 depending on the load

Y = wear [μm/km]

A = Cf53
B = hard-chromed
C = 304 stainless steel
D = HR carbon steel

Pink = oscillating
Blue = rotating

Medium

Resistance

Alcohols

Hydrocarbons

Greases, oils without additives

Fuels

Diluted acids

0 to -

Strong acids

-

Diluted alkalines

Strong alkalines

+ up to 0

+ resistant      0 partially resistant      - non-resistant
All information applies to room temperature [+20 °C]
Table 05: Chemical resistance of iglidur® UW

Chemical resistance
iglidur® UW plain bearings are resistant to diluted alkalis and very weak acids as well as solvents and all types of lubricants.

**
Electrical specifications**

Specific transitional resistance

<105Ωcm

Surface resistance

<105Ω

Radioactive radiation
Plain bearings made of iglidur® UW are resistant to a radiation intensity of up to 3 x 102Gy.

Maximum moisture absorption

at +23°C/50% r. humidity

0.2% weight

Max. moisture absorption

0.8% weight

Table 06: Moisture absorption of iglidur® UW

Moisture absorption
The moisture absorption of iglidur® UW plain bearings in ambient conditions is approximately 0.2%. The saturation limit submerged in water amounts to 0.8%. These values are so low that moisture expansion needs to be considered only in extreme cases.

Line chart with an ascending line between the X- and the Y-axis.

Diagram 10: Influence of moisture absorption

X = Moisture absorption [Gew.-%]
Y = Reduction of inner diameter [%]

Diameter
d1 [mm]

Shaft h9
[mm]

iglidur® UW
E10 [mm]

Housing H7
[mm]

up to 3

0 - 0.025

+0.014 +0.054

0 +0.010

> 3 up to 6

0 - 0.030

+0.020 +0.068

0 +0.012

> 6 up to 10

0 - 0.036

+0.025 +0.083

0 +0.015

> 10 up to 18

0 - 0.043

+0.032 +0.102

0 +0.018

> 18 up to 30

0 - 0.052

+0.040 +0.124

0 +0.021

> 30 up to 50

0 - 0.062

+0.050 +0.150

0 +0.025

>50 to 80

0 - 0.074

+0.060 +0.180

0 +0.030

>80 to 120

0 - 0.087

+0.072 +0.212

0 +0.035

> 120 up to 180

0 - 0.100

+0.085 +0.245

0 +0.040

Table 07: Important tolerances according to ISO 3547-1 after press-fit

Installation tolerances
iglidur® UW plain bearings are the standard for shafts with h-tolerance (recommended minimum: h9).

The bearings are designed for press-fit into a housing machined to a H7 tolerance. After being assembled into a nominal size housing, the inner diameter automatically adjusts to the E10 tolerances. For particular dimensions the tolerance differs depending on the wall thickness (please see product range table).

Consulting

I look forward to answering your questions

igus® (Pty) Ltd. +27 11 312 1848Write e-mail

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