ASTM D6595 Method for Wear Metals and Contaminants in Used Lubricating Oils
ASTM D6595 Standard Test Method for Determination of Wear Metals and Contaminants in Used Lubricating Oils or Used Hydraulic Fluids by Rotating Disc Electrode Atomic Emission Spectrometry
1. Scope
1.1 This test method covers the determination of wear metals and contaminants in used lubricating oils and used hydraulic fluids by rotating disc electrode atomic emission spectroscopy (RDE-AES).
1.2 This test method provides a quick indication for abnormal wear and the presence of contamination in new or used lubricants and hydraulic fluids.
1.3 This test method uses oil-soluble metals for calibration and does not purport to relate quantitatively the values determined as insoluble particles to the dissolved metals. Analytical results are particle size dependent and low results may be obtained for those elements present in used oil samples as large particles.
1.4 The test method is capable of detecting and quantifying elements resulting from wear and contamination ranging from dissolved materials to particles approximately 10 µm in size.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. The preferred units are mg/kg (ppm by mass).
1.6 This standard does not purport to address all the safety problems, if any, associated with its use. It is the responsibility of the user of this method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
3. Terminology
3.1 Definitions:
3.1.1 burn, vt - in emission spectroscopy, to vaporize and excite a specimen with sufficient energy to generate spectral radiation.
3.1.2 calibration, n - the determination of the values of the significant parameters by comparison with values indicated by a set of reference standards.
3.1.3 calibration curve, n - the graphical or mathematical representation of a relationship between the assigned (known) values of standards and the measured responses from the measurement system.
3.1.4 calibration standard, n - a standard having an accepted value (reference value) for use in calibrating a measurement instrument or system.
3.1.5 emission spectroscopy, n - measurement of energy spectrum emitted by or from an object under some form of energetic stimulation; for example, light, electrical discharge, and so forth.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 arc discharge, n - a self-sustaining, high current density, high temperature discharge, uniquely characterized by a cathode fall nearly equal to the ionization potential of the gas or vapor in which it exists.
3.2.2 check sample, n - a reference material usually prepared by a laboratory for its own use as a calibration standard, as a measurement control standard, or for the qualification of a measurement method.
3.2.3 contaminant, n - material in an oil sample that may cause abnormal wear or lubricant degradation.
3.2.4 counter electrode, n - either of two graphite electrodes in an atomic emission spectrometer across which an arc or spark is generated.
3.2.5 graphite disc electrode, n - a soft form of the element carbon manufactured into the shape of a disc for use as a counter electrode in arc/spark spectrometers for oil analysis.
3.2.6 graphite rod electrode, n - a soft form of the element carbon manufactured into the shape of a rod for use as a counter electrode in arc/spark spectrometers for oil analysis.
3.2.7 profiling, n - to set the actual position of the entrance slit to produce optimum measurement intensity.
3.2.8 standardization, n - the process of reestablishing and correcting a calibration curve through the analysis of at least two known oil standards.
3.2.9 uptake rate, n - the amount of oil sample that is physically carried by the rotating disc electrode into the arc for analysis.
3.2.10 wear metal, n - material resulting from damage to a solid surface due to relative motion between that surface and a contacting substance or substances.
