ASTM D943-17 pdf download.Standard Test Method for Oxidation Characteristics of Inhibited Mineral Oils.
4. Significance and Use 4.1 This test method is widely used for specification pur- poses and is considered of value in estimating the oxidation stability of lubricants, especially those that are prone to water contamination. It should be recognized, however, that correla- tion between results of this method and the oxidation stability of a lubricant in field service may vary markedly with field service conditions and with various lubricants. The precision statement for this method was determined on steam turbine oils. N OTE 1—Furthermore, in the course of testing a lubricant by this method, other signs of deterioration, such as sludge formation or catalyst coil corrosion, may appear that are not reflected in the calculated oxidation lifetime. The subcommittee responsible for this method is investigating the application ofalternative criteria for evaluation oflubricants using this test apparatus. Test Method D4310 is now available for sludge measure- ment. 5. Apparatus 5.1 Oxidation Cell, of borosilicate glass, as shown in Fig. 1, consisting of a test tube, condenser, and oxygen delivery tube. The test tube has a calibration line at 300 mL (maximum error 1 mL). This calibration applies to the test tube alone at 20 °C. 5.2 Heating Bath, thermostatically controlled, capable of maintaining the oil sample in the oxidation cell at a tempera- ture of 95 °C 6 0.2 °C, fitted with a suitable stirring device to provide a uniform temperature throughout the bath, and large enough to hold the desired number ofoxidation cells immersed in the heating bath to a depth of 390 mm 6 10 mm and in the heating liquid itself to a depth of 355 mm 6 10 mm. N OTE 2—Metal block heaters meeting the test method requirements may also be used. It is not known what types of heating baths were used in developing the precision statement. 5.2.1 Studies have suggested that direct sunlight or artificial light may adversely influence the results of this test. 5 To minimize effects of light exposure on the lubricant being tested, light shall be excluded from the lubricant by one or more of the following ways: 5.2.1.1 Use of heated liquid baths that are designed and constructed of metal, or combinations of metals and other suitable opaque materials, that prevent light from entering the test cell from the sides is preferred. If a viewing window is included in the design, this viewing window shall be fitted with a suitable opaque cover and be kept closed when no observa- tion is being made.
5.2.1.2 If glass heating baths are used, the bath shall be wrapped with aluminum foil or other opaque material.
5.2.1.3 Bright light entering the test cell from directly overhead can be eliminated by use of an opaque shield.
5.3 Flowmeter, with a capacity of at least 3 L ⁄h of oxygen, and an accuracy of 60.1 L ⁄h.
5.4 Heating Bath Thermometer—ASTM Solvents Distilla- tion Thermometer having a range from 72 °C to 126 °C, and conforming to the requirements for Thermometer 40C as prescribed in Specification E1, or for Thermometer 70C as prescribed in Specifications for IP Standard Thermometers. Alternatively, digital contact thermometers such as PRTs (plati- num resistance thermometers), thermistors, or thermocouples in accordance with Specification E2877 of equal or better accuracy may be used.
5.5 Oxidation Cell Thermometer, 3 having a range from 80 °C to 100 °C, graduated in 0.1 °C, total length—250 mm, stem diameter—6.0 mm to 7.0 mm, calibrated for 76 mm immersion. 6,7 Alternatively, digital contact thermometers such as PRTs, thermistors, or thermocouples in accordance with Specification E2877 of equal or better accuracy may be used.
5.6 Thermometer Bracket, for holding the oxidation cell thermometer, of 18-8 stainless steel, having the dimensions shown in Fig. 2. The thermometer is held in the bracket by two fluoroelastomer O-rings of approximately 5 mm inside diam- eter. Alternatively, thin stainless steel wire may be used.
5.7 Wire Coiling Mandrel, as shown in Fig. 3.
5.8 Abrasive Cloth, silicon carbide, 100 grit with cloth backing. 5.9 Syringes, glass, with Luer-Lok locking connectors, 10 mL and 50 mL capacities for sampling, and water additions, respectively. 5.10 Syringe Sampling Tube, Grade 304 stainless steel tubing, 2.11 mm in outside diameter, 1.60 mm in inside diameter, 559 mm 6 2 mm long, with one end finished at 90° and the other end fitted with a Luer-Lok female connector. The Luer-Lok connector is preferably of elastomeric material, such as polyfluorovinylchloride to provide a good seal with the syringe. 8,7 5.11 Stopper, for Luer fitting ofsyringe sampling tube, made of polytetrafluoroethylene or polyfluorovinylchloride. 9 5.12 Sampling Tube Holder, for supporting the syringe sampling tube, made of methyl methacrylate resin, having the dimensions shown in Fig. 4.
5.13 Sampling Tube Spacer, for positioning the end of the sampling tube above the sampling tube holder, made of a length of plastic tubing polyvinyl chloride, polyethylene, polypropylene, or polytetrafluoroethylene having an inside diameter of approximately 3 mm and 51 mm 6 1 mm length.ASTM D943 pdf download.