ASTM D3520 for Quenching Time of Heat-Treating Fluids
ASTM D3520 Standard Test Method for Quenching Time of Heat-Treating Fluids (Magnetic Quenchometer Method)
5. Apparatus
5.1 Magnetic Quenchometer, as shown in Figs. 1 and 2.
5.2 Furnace, Electric Muffle, with air atmosphere, capable of maintaining a temperature of 885 more or less 5°C (1625 more or less 9°F), as measured at the ball by the thermocouple prior to quenching, and fitted with (1) a clean ceramic base plate, for supporting the test ball, and (2) a No. 14 B&S gage Chromel-Alumel thermocouple probe (without a protection tube) inserted through a hole in a wall of the furnace, and positioned to contact the test ball.
NOTE 5 - A rheostat on the power supply may be used to provide a closer control of furnace temperature, or a separate thermocouple-connected controller near the heating elements can be used to minimize temperature overrides, or both may be used. Further, 1 by 2 by 3-in. heat sinks can be placed next to the area where the ball is to be placed to act as heat shields and provide a more uniform temperature in this particular area.
6. Materials
6.1 Ball, Chromized Nickel, having a diameter of 22.22 more or less 0.13 mm (0.875 more or less 0.005 in.), a weight of 50 more or less 2 g, and surface finish from 0.38 to 0.76 µm (15 to 30 µin.).
6.2 Reference Fluid.
NOTE 6 - Fluids used in cooperative testing covered in Annex A2 are suitable. Reference fluids TDL-VI-1 (35) the primary reference fluid and TDL-VI-1 (100X) the secondary standard are suitable.
NOTE 7 - The use of non-chromized nickel balls is not included in this test method and is not recommended since the results obtained are commonly more scattered and may be inconsistent with data properly obtained with chromized nickel balls. It is also recommended that chromized nickel balls be used with a final initialization value of 29.0 to 32.0 seconds to obtain optimal repeatability.
6.3 Stoddard Solvent, conforming to Specification D484. (Warning - Combustible, skin irritant on repeated contact, aspiration hazard.)
6.4 Precipitation Naphtha, conforming to the requirement for precipitation naphtha in Test Method D91. (Warning - Extremely flammable, skin irritant on repeated contact, aspiration hazard.)
6.5 Forceps, approximately 450 mm (18 in.) long. Weld two 20 mm (3/4 in.) stainless steel washers to the tips of the forceps for greater safety in transporting the hot nickel balls.
6.6 Tissue, lintless.
7. Preparation of Apparatus
7.1 Tester:
7.1.1 Place the instrument near the furnace and where lighting does not activate the photo cell.
7.1.2 Connect to 110 V ac.
7.1.3 Set the switch (Fig. 1, Item 2) to ON position.
NOTE 8 - The shield of the photo cell should be cleaned before each test with lintless tissue to ensure proper functioning.
NOTE 9 - The "horseshoe" magnet inside the instrument is positioned as close as possible to the beaker housing. Occasionally check the magnet and reposition if necessary.
7.2 Test Ball:
7.2.1 Apply Stoddard solvent. Dry with lintless tissue. Repeat.
7.2.2 Apply precipitation naphtha. Wipe off with lintless tissue. Repeat. Air dry, and remove any traces of lint.
NOTE 10 - Do not allow the solvents to evaporate from the ball. The solvents should be absorbed by the tissue. Avoid touching the ball with hands or any other sources of contamination.
7.3 Test Sample:
7.3.1 Determine water content per Test Method D1744.
7.3.2 If the water content is >0.03 %, then dry the oil sample prior to the test.
7.3.3 The oil is to be dried by heating the oil to 100°C (212°F) with agitation. Continue heating the oil at 100°C (212°F) with agitation until bubbling ceases (typically 1 to 2h).
NOTE 11 - It is not recommended that this test method be used with dirty quench oils, those oils with 0.5 % pentane insolubles, since dirty oils may lead to erroneous results and potentially damage the nickel ball.
NOTE 12 - Extreme care must be used to remove carbonaceous deposits or other residues which might be difficult to remove with Stoddard solvent. Attempts with fiber brushes, etc., must be carefully viewed, and if the ball does not appear satisfactory when tested in the standard fluid TDL-VI-1 (35) (see Annex A2), it should be discarded and a new ball put into use.
