8. Procedure
8.1 Preparation for New Test Set-Up for Reference Oil and Test Oils:
8.1.1 Insert the tied coupons in the test tube, positioning the squares vertically (so that the air tube can be inserted to touch the bottom of the test tube). Weigh the air tube, test tube, and contents together to within 0.1 g.
8.1.2 Add 100 +/- 1 mL of oil to the test tube, reweigh the air tube, test tubes, and contents together to within 0.1 g, and determine the weight of oil added.
8.1.3 Assemble the test tube and condenser and mount the assembly so that 30 +/- 5 cm of test tube is submerged in the bath with the sample operating at a temperature of 121 +/- 0.5°C.
8.1.4 Start the flow of cooling water through the condenser jacket.
8.1.5 Insert the air tube (orifice-end down) through the condenser and into the oil sample and support it so that its orifice is within 0.3 cm of the bottom of the tubes.
8.2 To begin testing connect the source of clean, dry air (5 +/- 0.5 L/h) to the air tube and allow the air to flow for 168 h.
8.3 End of Test - After 168 h at 121°C, shut off the air-flow, disassemble, and check test setup as follows:
8.3.1 Remove air supply and disconnect condenser.
8.3.2 Remove test tube from the constant-temperature bath, allow it to cool, and wipe off the outside of the tube with a naphtha-dampened cloth.
8.3.3 Re-weigh the air tube, test tube, and contents to within 0.1 g, determine weight of oil sample remaining, and compute the percentage of weight loss resulting from evaporation of oil (see 10.1). If the evaporation loss is greater than 8 %, leakage is present. Correct the leak, and repeat the determination, using fresh oil sample and new coupons.
8.3.4 Using forceps, withdraw the coupons from the test tube, and remove the wire holding them together. (Retain the test tube and sample for further examination).
8.4 Preparing Squares for Examination:
8.4.1 Using forceps, wash each square individually in tetrahydrofuran.
8.4.2 Repeat the washing, using fresh tetrahydrofuran, scrubbing the squares with the short-bristled brush until the tetrahydrofuran shows no additional discoloration. Use a piece of Kimwipe, dampened with acetone, to rub and wipe the coupons repeatedly until the tissue remains clean after wiping. Allow the squares to air-dry. The reaction products that are to be removed by this cleaning process may tend to have a stronger affinity to the bronze material, and therefore may be more difficult to remove from the bronze coupon. Improper removal of the reaction products from the coupons may result in inaccurate weight change measurements. With the bronze coupon, brushing may need to be more vigorous to remove the reaction products, but care must be taken not to scrub to the point where any of the coupon surfaces are being polished or abraded.
8.5 Examining Each Square:
8.5.1 Re-weigh each square to the nearest 0.1 mg and compute (in mg/cm2 of surface) the change in weight of each square (see 10.2).
8.5.2 Rate both sides of the copper coupon according to Test Method D130, and note the color of any stains present on the copper and bronze squares.
8.6 Examining the New Oil and the Oil Sample in the Test Tube:
8.6.1 Immediately after calibration of the ICP-AES instrument (as specified in Test Method D5185), use Test Method D5185 to determine, in duplicate, the concentration of copper, lead, and tin in both the new and used oil.
9. Reference Oil Testing
9.1 Test a TMC-coded reference oil along with each batch of non-reference oil tests. Run the reference oil simultaneously with, and in the same bath as, the non-reference oils.
NOTE 1 - Annex A1 discusses the involvement of the ASTM TMC with respect to the reference test monitoring program.
9.1.1 Prior to requiring a reference oil test, procure a supply of reference oils directly from the TMC. These oils have been formulated or selected to represent specific chemistry types, or performance levels, or both. Each reference oil sample is identified using a unique set of identification codes on the container labels. The coded reference samples provide for a blind reference testing program to protect against the possibility of bias in the results.
9.1.1.1 The testing laboratory tacitly agrees to use the TMC reference oils exclusively in accordance with the TMC's published Policies for Use and Analysis of ASTM Reference Oils, and to run and report the reference oil test according to TMC guidelines.
NOTE 2 - Policies for the Use and Analysis of ASTM Reference Oils is available from the TMC.
9.1.2 Request a reference oil assignment from the TMC for the CBT Test. The TMC shall determine the specific reference oil to be tested by the laboratory. Assignments shall be made by the TMC using the unique identifying codes on the reference oil container labels. Provide the TMC with the bath identification number for the test.
9.1.3 Run the TMC reference oil test according to the procedure and in the same manner as the non-reference oil test(s).
9.1.4 Reporting of Reference Oil Test Results - Report the results of all reference oil tests to the TMC according to the following directives:
9.1.4.1 Use the data reporting formats detailed in Annex A2 (see Figs. A2.1 through A2.4) for reporting all TMC reference oil test data to the TMC. Report only the reference oil results to the TMC; do not include any non-reference test data. Complete all of the required blank fields on the forms.
9.1.4.2 Transmit reference test data by electronic means, or by telephone facsimile, to the TMC immediately upon completion of the test analysis. Include all of the reporting forms in the transmission.
NOTE 3 - Specific protocols for the electronic transmission of test data to the TMC are available from the TMC.
9.1.4.3 In addition to the transmitted data, send by mail or other courier one copy of the completed standard final reference test report to the TMC. The signatory line on the mailed Final Report Cover Sheet (Fig. A2.1) requires an original signature by an authorized representative of the testing laboratory. This signature is not to be a copy or mechanically reproduced. The signature affirms the statements made in the affidavit on the Final Report Cover Sheet. Mail the final test report so that it is received at the TMC within 30 days from the test completion date.
9.1.5 Evaluation of Reference Test Oil Results - Upon receipt of the transmitted TMC reference oil test results, the TMC shall review the test for operational adherence to the published procedure. If the test is found to be operationally valid, the reference oil results shall be evaluated using acceptance criteria established by the governing surveillance panel. The reference oil acceptance criteria are subject to change at the discretion of the surveillance panel.
9.1.5.1 If the transmitted test is found to be both operationally valid and statistically acceptable the testing laboratory will be notified of the acceptable status of the reference test. The uncoded TMC reference oil identification will also be disclosed to the testing laboratory. The validity findings are considered preliminary until the formally signed final report of the data is received and reviewed by the TMC. Discrepancies between the initial transmitted data and the mailed final report may result in the suspension or reversal of the preliminary validity decision.
9.1.5.2 In the event that a TMC reference oil test is found to be unacceptable, an explanation of the problem relating to the failure shall be provided to the testing laboratory. If there is an obvious operational reason for the failed test, correct the problem before requesting another TMC reference oil assignment. If the reason for the fail is not obvious, recheck all test related equipment for compliance to the procedure and good laboratory practice. Following this recheck the TMC will assign another TMC reference oil for testing.
9.1.6 Status of Non-Reference Oil Tests Relative to TMC Reference Oil Tests - The batch of non-reference tests is considered valid only if the results of the TMC reference oil test meet the predetermined acceptance specifications for the particular reference oil tested.
10. Calculations
10.1 Evaporation Loss:
L = (W1 - W2)/W3 x 100
where:
L = percentage evaporation loss,
W1 = initial weight of the air tube, test tube and contents, including oil,
W2 = final weight of the air tube, test tube and contents, including oil, and
W3 = initial weight of oil sample.
10.2 Change in Metal Square Weight:
where:
M = change in metal weight per surface area, mg/cm2,
M1 = final weight, mg,
M2 = original weight, mg,
W = width of metal square, cm, and
Le = length of metal square, cm.
10.3 Change in Metal Concentration in the Used Oil:
C = C2 - C1
where:
C = change in metal concentration before and after test,
C1 = average of the duplicate measurement of metal concentration in new oil, and
C2 = average of the duplicate measurement of metal concentration in used oil.
10.3.1 Correction Factor - Apply a correction factor of 0.276 to the lead coupon batches designated by the Central Parts Distributor (CPD) with a serial number ending in "-A" or "-Cx" (where x denotes a number designating the coupon batch cut). Multiply non-reference test results for change in lead (C in 10.3) by this correction factor as follows:
CLead Corrected = CLead x 0.276
where:
CLead Corrected = corrected change in lead concentration, ppm, and
CLead = change in lead concentration, before and after test, ppm, as determined in 10.3.