ASTM D3603 Rust-Preventing Characteristics of Steam Turbine Oil
ASTM D3603 Standard Test Method for Rust-Preventing Characteristics of Steam Turbine Oil in the Presence of Water (Horizontal Disk Method)
7. Test Specimens and Their Preparation
7.1 The horizontal and vertical specimens (Fig. 7 and Fig. 8, respectively) are attached to one another, separated by a 2.4-mm (3/32-in.) fluorocarbon washer (Fig. 9 ). A methyl methacrylate cap (Fig. 10 ) is attached to the vertical specimen for handling.
7.2 The horizontal specimen when new shall be 30.2 mm(1 3/16 in.) in diameter and 4.8 mm (3/16 in.) thick, with a 6.4-mm (1/4-in.) central threaded shaft 9.5 mm (3/8 in.) long. Specimens should be discarded when they reach a thickness of 1.6 mm (1/16 in.) after repeated use.
7.3 The vertical specimen when new shall be 12.7 mm (1/2 in.) in diameter and 15.9 mm (5/8 in.) in length exclusive of the 9.5-mm (3/8-in.) threaded shaft which screws into the 15.9-mm plastic cap. Specimens should be discarded when they reach a diameter of 9.5 mm after repeated use.
7.4 Both specimens shall be made of steel conforming to Grade 1018 of Specification A 108, or to BS 970: 1955-EN3B.
NOTE 6 - When making a check test, the steel specimen that showed rust should not be reused. Specimens that repeatedly show rust in tests of various oils may be imperfect. Such specimens should be used with oils known to pass the test. If rusting occurs in repeat tests, these specimens should be discarded.
7.5 Both specimens, either new or from a previous test (previously used unrusted specimens shall be stored in isooctane) shall be prepared as described in 7.6 and 7.7.
7.6 Preliminary Grinding - If the specimens have been used previously and are free from rust or other irregularities, the preliminary grinding may be omitted, and they may be subjected only to final polishing as prescribed in 7.7. If the specimens are new or if any part of their surfaces show rust or other irregularities, clean them with ASTM precipitation naphtha or isooctane or IP 60/80 petroleum spirit and grind with medium 150-grit aluminum oxide cloth to remove all irregularities, pits, and scratches, as determined by visual inspection.
7.6.1 The specimen shall not be touched with the hands at any stage after cleaning with naphtha or isooctane or the petroleum spirit (which precedes either preliminary grinding or final polishing) until the test is completed. Forceps or a clean, lintless cloth may be used.
7.7 Final Polishing - Just before the test is to be made, polish the specimens with 240-grit aluminum oxide cloth. If the preliminary grinding has just been completed, stop the motor which rotates the specimen. Otherwise, remove the specimen from the isooctane (previously used unrusted specimens shall be stored in this reagent), dry with a clean cloth, and place in the chuck.
7.7.1 Vertical Specimen - When polishing a vertical specimen, rub a new piece of 240-grit aluminum oxide cloth longitudinally over the static specimen until the entire cylindrical surface shows visible scratches. Rotate the specimen at a speed of 1700 to 1800 r/min and polish with a strip of 240-grit aluminum oxide cloth by wrapping it halfway around the specimen, and applying a firm but gentle downward pull to the loose ends of the cloth to produce a uniform finely scratched surface free from longitudinal scratches. Carry out the final stages of the polishing with new cloth. Use only the cylindrical surface in evaluating the test. However, the flat end and shoulder adjacent to the threaded shaft should be rust free, not necessarily polished, at the start of the test.
7.7.2 Horizontal Specimen - When polishing a horizontal specimen, rub a new piece of 240-grit aluminum oxide cloth across the flat test surface until the entire surface shows visible straight scratches. Rotate the specimen at a speed of 1700 to 1800 r/min and polish with a strip of 240-grit aluminum oxide cloth by pressing firmly against the cloth with the flat of the thumb and slowly moving it back and forth, across the flat surface to produce a uniform finely scratched surface free from straight scratches. Carry out the final stages of the polishing with new cloth. Use only the flat surface in evaluating the test. However, the edge and surface adjacent to the shaft should be rust free, not necessarily polished, at the start of the test.
7.8 Assembly of Specimens - Before assembly, clean the fluorocarbon washer and plastic cap with ASTM precipitation naphtha, isooctane, or 60/80 petroleum spirit, and dry thoroughly. Attach the cap to the vertical specimen, and attach the horizontal specimen to the vertical specimen, separating them with the fluorocarbon washer.
NOTE 7 - Fig. 1 shows the arrangement of the apparatus.
