wear atlas (rus. атлас износа) — a specific image of wear particles, by characteristic features of which provide the type of wear of rubbing parts is determined.

Description

The wear atlas is required to determine the wear types of materials by tribodiagnostic methods.

By analysing the motor oil’s specter one can chart the wear atlas, which is a major part of the motor condition control because oil circulates through most important parts and assemblies. The typical wear particles in the oil system can mark evidence of the beginning of the process of degradation of the friction pairs to the level at which they may fail.

Generally, the spectral analysis of oil samples uses x-ray and optical emission analysers to determine the presence of metals in the oil. The particles of normal wear resemble flakes, with a diameter up to several micrometers and a thickness of less than one micron. Usually, they are completely burned in the emission spectrometer, and do not interfere with X-rays in further analysis.

But it is more important to detect particles of another class: those signaling abnormal wear and destruction. Abnormal wear particles may include particles of fatigue crumbling, scuffing, and microcutting. These particles have a different physical nature and signal different dangerous processes, but in terms of control they have one important common feature: they are considerably large, exceeding the size of normal wear particles by an order of magnitude.

One of the most efficient methods for monitoring those large destruction particles is through the use of optical particle counters, such as laser particle counter LNF-C. A sample feeder, operating as a peristaltic pump, supplies working oil to the control zone. The oil passes through a transparent cell where it is periodically scanned with a pulse laser, which enables the recording of the average impurity size. The overall image formed by coherent radiation passing through a sample is captured by a CCD-camera. The analyser registers and counts all particles greater than 4 microns. If the particle size exceeds 20 microns, it is automatically classified into the following categories:

- microcutting;

- scuffing;

- fatigue crumbling;

- non-metallic fibres.

Illustrations

A wear
  atlas piece.
A wear atlas piece.

Authors

  • Goryacheva Irina G.
  • Bronovets Marat A.

Sources

  1. International Journal of Condition Monitoring // The British Institute of NDT, 2007. —www.bindt.org/Publications/IJCM_Journal (reference date: 12.12.2011).
  2. Madhavan P., Steves M. et al. Lubricant Condition Monitoring Using Filter Debris Analysis // Noria Corporation, 2009. —www.oilanalysis.com/article_detail.asp?articleid=630 (reference date: 12.12.2011).

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