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WEAR LIFE TESTING

Journal Bearing Test | Timken Ring Block Test | Rider and Plate Test | Quality Control Testing

The best wear life tests are conducted with the actual assembled hardware, using techniques and procedures that are the same as those used in production, and tested in the same environment in which it is intended for use. Temperature and contamination environment and the same start-stop intervals and the same lull periods should be duplicated as closely as possible. However, time required to duplicate actual operating conditions may not be available, so the next best thing is the accelerated bench test. This type of test serves best as a screening tool.

In the following pages we will describe several different types of bench tests. Possibly there is one that is similar in geometry and mechanics to an application you have in mind. If so, you may be able to get some indication of whether or not Vitro-Lube will meet your needs. If your extrapolation shows promise, then this should be regarded as justification for an actual test of production components. The following test data were generated outside of our facilities.

JOURNAL BEARING TEST

This test technique was used by North American during the development of this coating and simulates typical air frame bearing usage. Figure 1 presents curves of cycle life versus loading at various temperatures, and Figure 2 compares Vitro-Lube to an accepted commercial sodium silicate bonded dry film lubricant. More details of this test technique and the results can be obtained by contacting NPI.

Journal bearing testing

 

Figure 1 presents curves of cycle life versus loading at various Temperatures

 

Figure 2 compares Vitro-Lube to an accepted commercial sodium silicate bonded dry film lubricant.

curves of cycle life versus loading at various Temperatures

 

compares Vitro-Lube to an accepted commercial sodium silicate bonded dry film lubricant.

 

TIMKEN RING AND CONFORMING BLOCK TEST (1996)

 

These tests were conducted using a timken ring and conforming block test machine (see figure 3) which subjects the coating to a unit pressure of 1900 psi, a speed of 50 cycles per minute (oscillating), an amplitude of oscillation of 60 degrees, and at room temperature. Test materials were 17-4 PH corrosion resistant steel. The following is a comparison between Vitro-Lube NPI-1220 and NPI-1220C.

PRODUCT

CYCLES

Vitro-Lube NPI-1220

197,000

Vitro-Lube NPI-1220C

335,000

Based on these results, the 1220C coating has been added to an existing user specification for use on newer design applications.

TIMKEN RING AND CONFORMING BLOCK TEST (1996)
Figure 3

 

RIDER AND PLATE TEST
(1968 - 1970) at +450°F

 

These tests were conducted using circular riders made of 440C stainless steel and flat rectangular plates made of 17-4PH stainless steel. Both the rider and the specimens was accomplished through an air cylinder and lever system. The flat plate was attached to a table and reciprocated under the rider by a mechanical drive system. The stress level at the contact area between the rider and the plate was 10,000 psi; the stroke length was one inch (two inches per cycle); the speed of reciprocation was 33 cycles per minute; and the test temperature was 450°F. Failure occurred when the friction coefficient reached 0.45.

RIDER AND PLATE TEST

 

This test program evaluated twenty-two commercial dry film lubricant products, the best of which are reported as follows:

 

QUALITY CONTROL TESTING

 

PIN AND V BLOCK (Falex Test)
This test technique is the one used at our facility, primarily as a quality control tool. It is conducted in accordance with ASTM test method D2625-69. This test is not considered to be a meaningful test in terms of predicting wear life as the test parameters and the geometry of the test specimens are not typical of those found in airframe hardware. The technique, however, does provide batch to batch performance verification as well as comparative data with other coatings. The following is a comparison of Vitro-lube NPI-1220 and 1220C based on batch check tests (1992-1997):

Product

Hours

Vitro-lube NPI-1220

8.8

Vitro-lube NPI-1220C

14.0

PIN AND V BLOCK (Falex Test)

 

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National Process Industries, Inc.
42250 Baldaray Circle, Temecula, CA. 92590
TEL: (951) 676-0343 • FAX: (951) 676-1549
Email : npi@npi-lube.com
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