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iglide® A181 - technical data

Material data

General Properties Unit iglide® A181 Testing Method
Density g/cm³ 1.38
Color blue
Max. moisture absorption at 73°F/50% r.h. % weight 0.2 DIN 53495
Max. moisture absorption % weight 1.3
Coefficient of surface friction, dynamic, against steel µ 0.10 - 0.21
p x v value, max. (dry) psl x fpm 8,750

Mechanical Properties
Modulus of elasticity psl 277,500 DIN 53457
Tensile strength at 68°F psl 6,962 DIN 53452
Compressive strength psl 8,702
Permissible static surface pressure (68°F) psl 4,496
Shore D-hardness 76 DIN 53505

Physical and Thermal Properties
Max. long-term application temperature °F 194
Max. short-term application temperature °F 230
Minimum application temperature °F -58
Thermal conductivity [W/m x K] 0.25 ASTM C 177
Coefficient of thermal expansion (at 73°F) [K-1 x 10-5] 11 DIN 53752

Electrical Properties
Specific volume resistance Ωcm < 1012 DIN IEC 93
Surface resistance Ω < 1012 DIN 53482
Table 01: Material properties


Permissible p x v values

Fig. 01: Permissible p x v values for iglide® A181 running dry against a steel shaft, at 68°F



Bearings made from iglide® A181 are suitable for application in direct contact with food. This means they are the ideal solution for bearing applications on machines used by the food and packaging industry and medical equipment manufacturers, among others.


deformation Figure 02: Deformation under load and temperatures
 
X = Pressure (psi)
Y = Deformatio [%]

Compressive Strength

With increasing temperatures, the compressive strength of iglide® A181 plain bearings decreases. The recommended maximum surface pressure is a mechanical material parameter. No conclusions regarding the tribological properties can be drawn from this. The graph at the right shows the elastic deformation of iglide® A181 during radial loading. At the recommended maximum surface pressure of 4,496 psi the deformation is less than 3%. Plastic deformation is minimal up to this radial load. However, it is also a result of the service time.


fpm Rotating Oscillating Linear
Continuous 158 118 689
Short Term 236 197 984
Table 02: Maximum surface speeds

Permissible surface speeds

iglide® A181 is developed for low surface speeds. Maximum speeds up to 158 fpm (rotating) and 689 fpm (linear) respectively are permitted for continuous use in dry operation. These given values indicate the limits at which an increase up to the continuous permissible temperature occurs. In practice these limit values are not always reached due to interactions.


iglide® A181 Application Temperature
Minimum - 58 °F
Max. long-term + 194 °F
Max. short-term + 230 °F
Additional axial securing + 140 °F
Table 03: Temperature limits

temprerature Figure 03: Recommended maximum static surface pressure if iglide® A181 as a result of the temperature (31 MPa to +68°F)
 
X = Temperature [°F]
Y = Pressure (psi)

Temperatures

The long-term upper temperature limit of +194°F permits broad use in applications with direct contact with food. As shown in the graph on the right, with increasing temperatures, the compressive strength decreases. When considering temperatures, the additional frictional heat in the bearing system must be taken into account.


Coefficients of friction Figure 04: Coefficients of friction of iglide® A181 as a function of the running speed; p = 108 psi
 
X = Surface speed [fpm]
Y = Coefficient of friction [μ]
Coefficients of friction Figure 05: Coefficients of friction of iglide® A181 as a function of the load, v = 1.97 fpm
 
X = Load [psi]
Y = Coefficient of friction [μ]

Friction and wear

Coefficient of friction and wear resistance alter with specific application parameters. For iglide® A181, the coefficient of friction μ is dependent on the surface speed of the shaft along with the shaft surface finish although generally speaking the effect is negligible as the table below represents. The coefficient of friction increases quickly with any load under 725 psi. As the load increases the coefficient of friction reduces drastically. For iglide® A181, a ground surface with an average between 8-64 rms is recommended, giving the user a wide range to work with.

iglidur® A181 Dry Grease Oil Water
Coefficients of Friction µ 0,05 - 0,23 0,09 0,04 0,04

Table 04: Coefficient of friction of iglide® A181 against steel (Shaft finish = 40 rms, 50 HRC)

A181 Figure 06: Coefficients of friction of iglide® A181 as a function of the shaft surface (1050 hard chromed)
 
X = Shaft Roughness [rms]
Y = Coefficient of friction [μ]

Fig. 07: Wear, rotating application with various Figure 07: Wear of iglide® A181 with different shaft materials in rotational applications p = 145 psi, v = 59 fpm
 
Y = Wear [μm/km]
 
A = Hard-anodized aluminum
B = Automatic screw steel
C = 1050 Steel
D = 1050, hard chromed
E = HR Carbon Steel
F = 304 Stainless
G = 440B Steel

Shaft Materials

The graphs show the test results of iglide® A181 bearings running against various shaft materials. Particular attention is paid in the food industry to corrosion-resistant shafts. The chart below shows that very low wear rates can be achieved in combination with these shafts. As with many of the iglide® materials, wear rate increases with otherwise identical parameters in rotation.

Fig. 08: Wear in oscillating and rotating Fig. 08: Wear of iglide® A181 with different shaft materials in rotational applications
 
A = Rotating
B = Oscillating
 
X = Pressure [psi]
Y = Wear [μm/km]
 
Fig. 09: Wear with different shaft materials Fig. 09: Wear with different shaft materials, oscillating and rotating movement p = 290 psi
 
X = Pressure [psi]
Y = Wear [μm/km]

Medium Resistance
Alcohol +
Hydrocarbons, chlorinated +
Greases, oils without additives +
Fuels +
Weak acids 0 to -
Strong acids -
Weak alkaline +
Strong alkaline + to 0
+ resistant      0 conditionally resistance      - not resistant
All specifications at room temperature (+68°F)
Table 05: Chemical resistance of iglide® A181


Electrical Properties

Specific volume resistance < 1012 Ωcm
Surface resistance < 1012 Ω
iglide® A181 bearings are electrically insulating.

Chemical Resistance

iglide® A181 bearings can be used under various environmental conditions and in contact with numerous chemicals. Table 05 gives an overview of the chemical resistance of iglide® A181 bearings at room temperature.

Radioactive Resistance

Plain bearings made of iglide® A181 are resistant to radiation up to an intensity of 2 · 102 Gy.

UV-Resistance

iglide® A181 bearings are only conditionally resistant to UV radiation.

Vacuum

When used in a vacuum environment, the iglide® A181 bearings release moisture as a vapor. Therefore, only dehumidified bearings are suitable in a vacuum environment.


Maximum moisture absorption
At 73 °F/50 % r.h. 0,2 weight-%
Max. water absorption 1,3 weight-%
Table 06: Moisture absorption

Fig. 10: Effect of moisture absorption on iglide® A181 plain Fig. 10: Effect of moisture absorption on iglide® A181 plain

X = Moisture absorption (weight %)
Y = Reduction of the inner diameter (%)

Moisture absorption

The moisture absorption of iglide® A181 bearings is approximately 0.2% in standard atmosphere. The saturation limit submerged in water is 1.3%. This must be taken into account for these types of applications.


For Metric Size Bearings

Length Tolerance (b1) Length of Chamfer (f)
Length (mm) Tolerance (h13)
(μm)
Based on d1
1 to 3 -0 /-140 f = 0.3 ➝ d1 1 - 6 mm
> 3 to 6 -0 /-180 f = 0.5 ➝ d1 > 6 - 12 mm
> 6 to 10 -0 /-220 f = 0.8 ➝ d1 > 12 - 30 mm
> 10 to 18 -0 /-270 f = 1.2 ➝ d1 > 30 mm
> 18 to 30 -0 /-330  
> 30 to 50 -0 /-390  
> 50 to 80 -0 /-460  

Table 07: Important tolerances iaw. ISO 3547-1 after press-fitting.

Installation tolerances

iglide® A181 plain bearings are meant to be oversized before being pressfit. After proper installation into a recommended housing bore, the inner diameter adjusts to meet our specified tolerances. Please adhere to the catalog specifications for housing bore and recommended shaft sizes. This will help to ensure optimal performance of iglide® plain bearings.