iglidur® L250 - material data

The most important specifications at a glance

iglidur L250 is a plain bearing material for high speed, fast sliding movements and low coefficient of friction. The iglidur L250 material plays to its strengths particularly with low loads. Applications that make use of these advantages are fans, small motors, fast-running sensors or magnet technology.

Descriptive technical specifications
Wear resistance at +23°C	- 🟧 🟧 🟧 ⬜️ ⬜️ +	More information on wear resistance
Wear resistance at +90°C	- 🟧 🟧 🟧 ⬜️ ⬜️ +
Wear resistance at +150°C	- 🟧 🟧 ⬜️ ⬜️ ⬜️ +
Slide property	- 🟧 🟧 🟧 🟧 🟧 +	Coefficient of friction, dynamic, against steel: µ 0.08 - 0.19
Wear resistance under water	- 🟧 ⬜️ ⬜️ ⬜️ ⬜️ +
Media resistance	- 🟧 🟧 🟧 ⬜️ ⬜️ +	More information on media resistance
Resistant to edge pressures	- 🟧 🟧 🟧 🟧 ⬜️ +
Resistant to shock and impact loads	- 🟧 🟧 🟧 🟧 ⬜️ +
Dirt resistance	- 🟧 🟧 🟧 ⬜️ ⬜️ +

When do I use this material?

For rotating applications at high speed
When the highest service life is required
For low load applications
When a low noise level is required
For very low coefficient of friction

When do I use a different material?

In case of high compressive strength -> iglidur Q, iglidur W300
When continuous operating temperatures are higher than +90°C -> iglidur V400
When you require low moisture absorption -> iglidur H1, iglidur J

Download data sheet

Temperatures

iglidur L250 plain bearings can be used at short-term temperatures of up to 180°C. Please bear in mind that a mechanical securing of the bearings is recommended from temperatures starting at 55°C. Higher temperatures can also cause the plain bearings to lose their press-fit and move in the hole.

Temperatures, coefficient of thermal expansion

Min. application temperature	Upper application temperature, long-term	Upper application temperature, short-term	In addition secure axially from
-40°C	+90°C	+180°C	+55°C

Permissible surface speeds

iglidur L250 has been developed especially for high surface speeds with low loads. Apart from the physical limit, which is determined by the increasing temperature of the bearing, the coefficient of wear also has a limiting effect when long sliding distances occur quickly at high peripheral speeds and the permissible wear limit is reached prematurely as a result. The maximum speeds are shown in the table.

Surface speeds of various iglidur materials

Maximum surface speeds [m/s]	Rotating	Oscillating	Linear
Long-term	1.0	0.7	2.0
Short-term	1.5	1.1	3.0

Permissible pv values

pv value, max. (dry)

MPa · m/s

0.40

Information on the pv value and lubrication

Mechanical properties

The maximum recommended surface pressure is a mechanical material parameter. No conclusions regarding the tribological properties can be drawn from it. With increasing temperatures, the compressive strength of iglidur L250 plain bearings decreases. Diagram 02 illustrates this inverse relationship. Diagram 03 shows the elastic deformation of iglidur L250 under radial loads. At the maximum recommended surface pressure of 45MPa, the deformation is less than 3%. A plastic deformation can be negligible up to this value. However, it also depends on the impact.

Friction and wear

In the best pairing (with shafts made of 304 stainless steel), a coefficient of friction of 0.14 is achieved even at low loads. A coefficient of friction below 0.1 was measured even at 10MPa (Diagrams 04 and 05).

Coefficient of friction against steel (Ra = 1µm, 50HRC):

iglidur L250	dry	Greases	Oil	Water
Coefficient of friction μ	0.08 - 0.19	0.09	0.04	0.04

Shaft materials

As seen in diagram 06, many shafts are recommendable for low loads and low rotations. The low coefficient of friction is additionally retained over a wide range of recommendable shaft surfaces finish. For loads higher than 1MPa, particular attention should be paid to the shaft material used.

Further information on shaft materials

Chemical resistance

iglidur L250 plain bearings are resistant to diluted alkalis and very weak acids as well as solvents and all types of lubricants.

All data at room temperature [+20 °C], + resistant 0 conditionally resistant - non-resistant

Chemicals	Resistance
Alcohols	+ up to 0
Greases, oils without additives	+
Hydrocarbons	+
Fuels	+
Strong alkalines	0
Strong acids	-
Diluted alkalines	+
Diluted acids	0 to -

Moisture absorption

With regard to applications where the smallest bearing clearances are concerned, please take the moisture absorption into consideration.

Maximum moisture absorption

at +23°C/50% r. humidity

0.7% weight

Maximum water absorption

3.9% weight

Installation tolerances

iglidur L250 plain bearings are standard bearings for shafts with h-tolerance (recommended minimum h9). After being fitted into a nominal size housing, the bearing's inner diameter automatically adjusts to the E10 tolerances. For particular dimensions the tolerance differs depending on the wall thickness (please see product range).

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

Diameter d1 [mm]	Housing H7 [mm]	iglidur L250 plain bearing E10 [mm]	Shaft h9 [mm]
up to 3	+0.000 +0.010	+0.014 +0.054	-0.025 +0.000
> 3 up to 6	+0.000 +0.012	+0.020 +0.068	-0.030 +0.000
> 6 up to 10	+0.000 +0.015	+0.025 +0.083	-0.036 +0.000
> 10 up to 18	+0.000 +0.018	+0.032 +0.102	-0.043 +0.000
> 18 up to 30	+0.000 +0.021	+0.040 +0.124	-0.052 +0.000
> 30 up to 50	+0.000 +0.025	+0.050 +0.150	-0.062 +0.000
>50 to 80	+0.000 +0.030	+0.060 +0.180	-0.074 +0.000
>80 to 120	+0.000 +0.035	+0.072 +0.212	-0.087 +0.000
> 120 up to 180	+0.000 +0.040	+0.085 +0.245	-0.100 +0.000

Thermal conductivity

[W/m · K] 0.24

ASTM C 177

Coefficient of thermal expansion

(at +23°C) [K-1 · 10-5] 10

DIN 53752

Compressive strength

47MPa

Vacuum

In a vacuum, any present moisture is released as vapour. You can only use dry iglidur L250 bearings in a vacuum.

Radiation resistance

Plain bearings made from iglidur L250 are resistant to a radiation intensity of 3 · 104Gy. Higher radiation weakens the material and may result in a significant decrease in its mechanical properties.