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iglide® J2 - Material data
Material table
| General features | Unit | iglide® J2 | test method |
|---|---|---|---|
| Density | g/cm3 | 1,44 | |
| Color | light-yellow | ||
| Max. humidity absorption at 73°F/50% R. H. | % weight | 0,2 | DIN 53495 |
| Max. water absorption | % weight | 1,3 | |
| Coefficient of surface friction, dynamic, against steel | µ | 0,11 - 0,27 | |
| PV values max. (dry) | PSI - ft/min | 6,600 | |
| Mechanical properties | |||
| Bending E-module | psi | 522,860 | DIN 53457 |
| Tensile strength at +68 °F | psi | 14,648 | DIN 53452 |
| Compressive strength | psi | 11,167 | |
| Maximum recommended surface pressure (68° F) | psi | 6,670 | |
| Shore D hardness | n.b. | DIN 53505 | |
| Physical and thermal properties | |||
| Max. long term application temperature | °F | +194 | |
| Max. short term application temperature | °F | +230 | |
| Lower application temperature | °F | -58 | |
| Heat conductivity | [W/m x K] | 0,25 | ASTM C 177 |
| Coefficient of thermal expansion (at 73° F) | [K-1 x 10-5] | 7 | DIN 53752 |
| Electrical properties | |||
| Specific forward resistance | Ωcm | > 1013 | DIN IEC 93 |
| Surface resistance | Ω | > 1012 | DIN 53482 |
Figure 01: Permitted pv-values for iglide® J2 bearings with 1 mm wall thickness in dry operation against a steel shaft, at +68°F, installed in a steel housing.
X = Sliding speed [ft/min]
Y = Load [psi]
With respect to its general mechanical and thermal specifications, iglide® J2 is directly comparable to our classic, iglide® J. In terms of mechanical properties, such asmaximum recommended surface pressure, however,iglide® J2 is superior to iglide® J. Sights should, on the other hand,be lowered with regard to the wear resistance in dry-running operation.
Figure 02: Maximum recommended surface pressure dependent on the temperature (6,672 psi to +68 °F)
X = Temperature [°F]
Y = Load [psi]
Mechanical properties
With increasing temperatures, the compressive strength of iglide® J2 plain bearings decreases. Fig. 02 clarifies this connection. Maximum recommended surface pressure represents a mechanical material parameter. Tribological conclusions cannot be drawn from it.
Figure 03: Deformation under load and temperatures
X = Load [psi]
Y = Deformation [%]
Figure 03 shows the elastic deformation of iglide® J2 with radial loads. A potential plastic deformation depends, among other things, on the length of exposure.
Permitted surface speeds
iglide® J2 is predominantly suitable for low speeds and dry running conditions; the limit values indicated in Table 02 can only be achieved at very low pressure loads. At the specified speeds, an increase in temperature up to the long-term permitted value can occur due to friction. In practice these limit values are not always reached.
| ft/min | rotary | oscillating | linear |
|---|---|---|---|
| Constant | 157 | 137 | 590 |
| Short-term | 374 | 216 | 984 |
Temperatures
The temperatures prevailing in the bearing system also have an influence on the bearing wear. The wear increases with rising temperatures, and the influence is especially marked from 194°F temperature onward. An additional securing is recommended at temperatures higher than +140°F.
| iglide® J2 | Application temperature |
|---|---|
| Lower | - 122 °F |
| Upper, long-term | + 194 °F |
| Upper, short-term | + 230 °F |
| Secure axially in addition | + 140 °F |
| Table 03: Temperature limits for iglide® J2 |
Friction and wear
The coefficient of friction and wear resistance depend on the application parameters (Fig. 04 and 05).
| iglide® J2 | Dry | Grease | Oil | Water |
|---|---|---|---|---|
| Coefficients of friction µ | 0,11 - 0,27 | 0,08 | 0,07 | 0,04 |
| Table 04: Coefficients of friction for iglide® J2 against steel (Ra = 1 µm, 50 HRC) |
Fig. 06: Wear, rotating application with various shaft materials p = 145 psi, v = 59 ft/min
X = shaft materials
Y = wear [μm/km]
A = Aluminum, hard-anodized
B = machining steel
Shaft materials
Friction and wear also depend to a high degree on the reverse partner. Very smooth shafts increase the coefficient of both friction and wear. Figure 06 shows an excerpt of the results of tests with different shaft materials. Fig. 06 showsthat when rotating under 145 psi, iglide® J2has the best wear coefficients with machining steel. Duringdry-running operations, the wear coefficients on other shaftsare sometimes far higher.
Unlike many other iglidea® materials, thewear rate is slightly higher with pivoting movements thanwith rotational movements with otherwise identical parameters(Fig. 07).
Further properties
Chemical resistance
iglige® J2 bearings are resistant to diluted alkali's and very weak acids as well as to fuels and all kinds of lubricants. The low humidity absorption allows them to be used in wet or humid environment. Plain bearings made from iglide® J2 are resistant to a wide range of cleaning agents used in the food industry.
Radioactive rays iglide® J2 bearings are radiation resistant up to a radioactive intensity of 3 • 102 Gy.
UV-resistant iglide® J2 bearings change color under the influence of UV rays. However the hardness, compressive strength and the wear resistance of the material do not degrade.
VacuumIn application in vacuum, the potentially existent moisture content is degassed. For this reason only the dry iglide® J2 bearings are suitable for vacuum.
| Medium | Resistance |
|---|---|
| Alcohols | + |
| Hydrocarbons | + |
| Greases, oils without additives | + |
| Fuels | + |
| Diluted acids | 0 to - |
| Strong acids | - |
| Diluted bases | + |
| Strong bases | + to 0 |
| + resistant 0 conditionally resistant - non-resistant | |
| All specifications at room temperature[+68 °F] | |
| Table 05: Chemical resistance of the iglide® bearings J2 |
Electrical properties
iglide® J2 bearings are electrically insulating.
| Specific forward resistance | Surface resistance |
|---|---|
| > 1013 Ωcm | > 1012 Ω |
Moisture absorption
The humidity absorption of iglide® J2 bearings amounts to about 0.2 % in standard climatic conditions. The saturation limit in water is 1,3 %. These values are so low that a moisture expansion need to be considered only in extreme cases.
| by 73 °F/50 % r. F. | Max. water absorption |
|---|---|
| 0,2 Wt.-% | 1,3 Wt.-% |
| Table 06: Humidity absorption of iglide® J2 |
Installation tolerances
iglide® J2 bearings are standard bearings for shafts with h-tolerance (recommended minimum h9). The bearings are designed for press-fit in a housing with h7 tolerance. After the installation in a housing with nominal diameter, the inner diameter of the bearing automatically adjusts to the E10 tolerance. Compared to the installation tolerance, the inner diameter varies according to moisture absorption.
| Diameter d1 [mm] | Shaft h9 [mm] | iglide® J2 E10 [mm] | Housing H7 [mm] |
|---|---|---|---|
| Up to 3 | 0 - 0,025 | +0,014 +0,054 | 0 +0,010 |
| > 3 to 6 | 0 - 0,030 | +0,020 +0,068 | 0 +0,012 |
| > 6 to 10 | 0 - 0,036 | +0,025 +0,083 | 0 +0,015 |
| > 10 to 18 | 0 - 0,043 | +0,032 +0,102 | 0 +0,018 |
| > 18 to 30 | 0 - 0,052 | +0,040 +0,124 | 0 +0,021 |
| > 30 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 to 180 | 0 - 0,100 | +0,085 +0,245 | 0 +0,040 |
| Table 07: Important tolerances for iglide® J2 bearings according to ISO 3547-1 after the press-in. |