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
10. Preparation of Test Specimen
10.1 Homogenization - Used oil samples may contain particulate matter and, in order to be representative, must always be vigorously shaken prior to pouring a test specimen for analysis.
10.2 Ultrasonic Homogenization - Samples that have been in transit for several days, idle in storage or very viscous, shall be placed in a heated ultrasonic bath to break up clusters of particles and to bring them back into suspension. The samples shall be vigorously shaken after being in the ultrasonic bath and prior to pouring a test specimen for analysis. The bath temperature shall be at least 60°C and the total agitation time at least 2 min.
10.3 Specimen Holders - Used oil samples and oil standards shall be poured into a specimen holder of at least 1 mL capacity prior to analysis. Exercise care to pour the sample consistently to the same level in the specimen holders to maintain good repeatability of analysis.
10.4 Specimen Table - The specimen table shall be adjusted so that when it is in the fully raised position, at least one-third of the disc electrode is immersed in the oil test specimen.
11. Preparation of Apparatus
11.1 Warm-up Burns - If the instrument has been idle for several hours, it may be necessary to conduct at least three warm-up burns to stabilize the excitation source. The warm-up procedure can be performed with any oil sample or standard. Consult the manufacturer's instructions for specific warm-up requirements.
11.2 Optical Profile - Perform the normal optical profile procedure called for in the operation manual of the instrument. An optical profile shall also be performed if the instrument has been inoperative for an extended period of time or if the temperature has shifted more than 10°C since the last calibration check.
11.3 Validation Check - A go/no go standardization check can be performed with one or more check samples to confirm calibration prior to the analysis of routine samples. A calibration standard or known oil sample can be used for this purpose. The optical profile and standardization routine recommended by the instrument manufacturer shall be performed if the validation check fails to meet the more or less 10 % accuracy guidelines for each element of interest.
