iglidur® RW370 – material data

Diagram 02: Recommended maximum surface pressure of a function of temperature (75 MPa at +20 °C)
 
X = Temperature [°C]
Y = Load [MPa]

Mechanical properties

With increasing temperatures, the compressive strength of iglidur® RW370 plain bearings decreases. The diagram 02 shows this inverse relationship. The recommended maximum surface pressure is a mechanical material parameter. No conclusions regarding the tribological properties can be drawn from this.

Diagram 03: Deformation under pressure and temperature
 
X = Load [MPa]
Y = Deformation [%]

Diagram 03 shows the elastic deformation of iglidur® RW370 at radial loads. A possible deformation could be, among others, dependant on the duty cycle of the load.

Maximum running speed

m/s	Rotating	Oscillating	linear
Long-term	0,9	0,6	2,5
Short-term	1,0	0,8	2,6

Table 02: Maximum surface speeds

Permissible surface speeds

Even if the typical applications for iglidur® RW370 plain bearings are generally for intermittent service, depending on the type of motion, the maximum attainable speeds can be quite high. The speeds stated in table 03 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 pv value.

iglidur® RW370	Application temperature
Minimum	-50°C
Max. long-term	+170°C
Maximum, short-term	+190°C
In addition secure axially from	+120°C

Table 03: Temperature limits

Temperature

The short-term permissible temperature limit is +190°C, thus permitting the use of iglidur® RW370 plain bearings in all applications with elevated ambient temperatures. With increasing temperatures, the compressive strength of iglidur® RW370 plain bearings decreases. When considering temperatures, the additional frictional heat in the bearing system must be taken into account. For temperatures over +120°C an additional securing is required.

Diagram 04: Coefficient of friction as a function of the surface speed, p = 1MPa
 
X = Surface speed [m/s]
Y = Coefficient of friction μ

Friction and wear

The excellent coefficient of friction level of iglidur® RW370 in dry operation decreases with speed, to a value of 1.1 m/s. Diagram 04 shows this with respect to a steel shaft. Above a speed of 1.25 m/s the coefficient of friction increases significantly as the load limit of the material is reached.
 

iglidur® RW370	Dry	Greases	Oil	Water
C. o. f. µ	0,13 - 0,17	0,09	0,04	0,04

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

Diagram 05: Wear, rotating with different shaft materials, pressure, p = 1MPa, v = 0.3m/s
 
X = Shaft material
Y = Wear [μm/km]

Diagram 06: Wear for oscillating and rotating applications with shaft material Cf53 hardened and ground steel, as a function of the load
 
X = Load [MPa]
Y = Wear [μm/km]

Shaft materials

Diagrams 05 and 06 display a summary of the results of tests with different shaft materials conducted with plain bearings made from iglidur® RW370. At a surface pressure of 0.3m/s and 1MPa, shafts made of hard-anodised aluminium and hard-chromed Cf53 are the most suitable glide surfaces. Shafts made from 304 stainless steel or high grade steel also show good results. If the shaft material you plan on using is not shown in these test results, please contact us.

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

+ resistant      0 limited resistance      - non-resistant
 
All information given at room temperature [+20°C]
Table 04: Chemical resistance

Moisture absorption

The moisture absorption of iglidur® RW370 plain bearings is below 0.25% weight in ambient conditions. The saturation limit in water is 1.2 %weight.

Radiation resistance

Plain bearings made from iglidur® RW370 are resistant up to a radiation intensity of 3 · 10² Gy.

UV resistance

When subjected to UV radiation, iglidur® RW370 plain bearings change colour. However, hardness, compressive strength and wear resistance of the material do not change.

Vacuum

In vacuum, the moisture content is released as vapour. Due to its low moisture absorption, use in a vacuum is possible.

Electrical properties

Specific volume resistance	> 1012 Ωcm
Surface resistance	> 1012 Ω

Ø d1 [mm]	Housing H7 [mm]	Plain bearing F10 [mm]	Shaft h9 [mm]
to 3	+0,000 +0,010	+0,006 +0,046	-0,025 +0,000
> 3 to 6	+0,000 +0,012	+0,010 +0,058	-0,030 +0,000
> 6 to 10	+0,000 +0,015	+0,013 +0,071	-0,036 +0,000
> 10 to 18	+0,000 +0,018	+0,016 +0,086	-0,043 +0,000
> 18 to 30	+0,000 +0,021	+0,020 +0,104	-0,052 +0,000
> 30 to 50	+0,000 +0,025	+0,025 +0,125	-0,062 +0,000
> 50 to 80	+0,000 +0,030	+0,030 +0,150	-0,074 +0,000
> 80 to 120	+0,000 +0,035	+0,036 +0,176	-0,087 +0,000
> 120 to 180	+0,000 +0,040	+0,043 +0,203	+0,000 +0,100

Table 05: Important tolerances for plain bearings according to ISO 3547-1 after press-fit

 

Installation tolerances

iglidur® RW370 plain bearings are standard bearings 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, in standard cases the inner diameter automatically adjusts to the F10 tolerances. For particular dimensions the tolerance differs depending on the wall thickness (please see product range table).