ASTM D2619-21

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2619 − 09 (Reapproved 2014) D2619 − 21
Standard Test Method for
Hydrolytic Stability of Hydraulic Fluids (Beverage Bottle
Method)
This standard is issued under the fixed designation D2619; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This test method covers the determination of the hydrolytic stability of petroleum or synthetic-based hydraulic fluids.
NOTE 1—Water-based or water-emulsion fluids can be evaluated by this test method, but they are run “as is.” Additional water is not added to the 100 g
sample. In these cases, the person requesting the test needs to let the test operator know that water is present.
1.2 The values stated in SI units are to be regarded as the standard. The English units given in parentheses are provided for
information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Specific warning statements are given in 3.1, 6.1, 6.3, 6.9 and Annex A1.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D130 Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test
D664 Test Method for Acid Number of Petroleum Products by Potentiometric Titration
D974 Test Method for Acid and Base Number by Color-Indicator Titration
3. Summary of Test Method
3.1 A copper test specimen and 75 g of test fluid plus 25 g of water (or 100 g of a water-containing fluid) are sealed in a
pressure-type beverage bottle. The bottle is rotated, end for end, for 48 h in an oven at 93 °C (200 °F). Layers are separated and
the weight change of the copper specimen is measured. The acid number change of the fluid and acidity of the water layer are
determined. (Warning—In addition to other precautions, because this test method involves the use of a glass bottle that may
contain approximately 200 kPa (2 atm) of air and water vapor at temperatures up to 93 °C, a full face shield and heavy woven
fabric gloves should be worn when handling or working with the heated and sealed sample container.)
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of Subcommittee
D02.N0 on Hydraulic Fluids.
Current edition approved Oct. 1, 2014May 1, 2021. Published November 2014June 2021. Originally approved in 1967. Last previous edition approved in 20092014 as
D2619 – 09.D2619 – 09 (2014). DOI: 10.1520/D2619-09R14.10.1520/D2619-21.
This test method is a modification of Federal Test Method Standard No. 791a, Method 3457 for Hydrolytic Stability.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2619 − 21
4. Significance and Use
4.1 This test method differentiates the relative stability of hydraulic fluids in the presence of water under the conditions of the test.
Hydrolytically unstable hydraulic fluids form acidic and insoluble contaminants which can cause hydraulic system malfunctions
due to corrosion, valve sticking, or change in viscosity of the fluid. The degree of correlation between this test method and service
performance has not been fully determined.
5. Apparatus
5.1 Air Oven, convection, adjusted to 93 °C 6 0.5 °C (200 °F 6 1 °F).
5.2 Pressure-Type Beverage Bottles, 200 mL (7 oz). 200 mL (7 oz), as shown in Fig. 1. It is not essential that bottles conform
exactly to the dimensions shown as long as they fit securely in the holders and caps do not leak. Bottles with straight sides and
FIG. 1 Beverage Bottle
TABLE 2 H O Acidity (mg KOH)
Repeatability Reproducibility Repeatability Reproducibility
Average,
Fluid Standard Deviation, Standard Deviation, Limit, Limit,
X¯
s s r R
r R
1 2.3267 0.5684 1.1103 1.5916 3.1088
2 0.3458 0.2156 0.4694 0.6038 1.3143
3 15.2358 1.4479 3.6158 4.0542 10.1244
4 0.6025 0.3282 0.5146 0.9190 1.4409
5 0.6533 0.2929 0.4413 0.8202 1.2355
Bottles can be obtained from suppliers of the test apparatus or from beverage distributors.
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a narrower neck are also marketed for this application but there are some reports of breakage during use as the copper coupon will
move with greater velocity during the rotation. The curved sides help to slow the movement of the coupon.
5.3 Capping Press, for bottles.
5.4 Rotating Mechanism, for holding bottles and rotating end over end at 5 r ⁄min in oven.
5.5 Büchner FunnelFiltration Assembly and Filter Flask.
5.6 Water Aspirator.Vacuum source, for filtration.
5.7 Typewriter Brush.
5.7 Separatory Funnel, 125 mL.
5.8 Balance, sensitive to 0.2 mg.
5.9 Caps, for sealing bottles.
5.10 Inert Seal, for cap gasket, 0.127 mm (0.005 in.) thick fluorocarbon seal.
6. Reagents and Materials
6.1 n-Heptane. (Warning— Flammable, harmful if inhaled, skin irritant on repeated contact, aspiration hazard; see A1.1.)
6.2 Phenolphthalein, 1 % alcoholic solution.
6.3 Potassium Hydroxide (KOH), 0.1 N aqueous solution standardized to within 0.0005 N. (Warning—Caustic.)
6.4 Copper Strip (QQ-C-576A), 16-22 B and S gage, 13 mm by 51 mm.
6.5 Steel Wool, grade 1-medium medium fine.
6.6 LitmuspH Paper.
6.7 Filter Paper, Whatman No. 41.
6.8 Anhydrous Sodium Sulfate (Na SO ).
2 4
6.9 1,1,1-Trichloroethane (optional–for use when the test fluid is a phosphate ester). (Warning—Harmful if inhaled, high
concentrations may cause unconsciousness or death; contact may cause skin irritations and dermatitis, may produce toxic vapors
if burned, eye irritant; see A1.2.)
7. Procedure
7.1 Fill the pressure beverage bottle with distilled water and allow to stand overnight. Drain and rinse with fresh distilled water,
but do not dry.
7.2 Determine the total acid number of the test fluid in accordance with Test Method D664 or D974.
7.3 Weigh 75 g of test fluid and 25 g of distilled water (or in the case of water-containing fluids, 100 g of the test fluid) to 0.5 g
into the beverage bottle.
D2619 − 21
7.4 Polish the copper test specimen (including the edges) to a clean surface with the steel wool and wash with n-heptane.
(Warning—see 6.1.) Dry and weigh to 0.2 mg. Immediately immerse the copper specimen in the fluid in the beverage bottle. Avoid
specimen contact by handling the cleaned copper test strip with cotton gloves or filter paper.
7.5 Prepare a disk of the inert seal and place in a new bottle cap. Seal the bottle using the cap with the gasket. Invert the bottle
for 5 min to check for leakage. If it leaks, start over in 7.3 with a fresh sample.
7.6 Place the bottle in the rotating mechanism in the oven adjusted to 93 °C 6 0.5 °C (200 °F 6 1 °F). Allow to rotate, end for
end, at 5 r ⁄min for 48 h.
7.7 Remove the bottle from the oven and place on an insulated surface until cool.surface, allowing it to cool for approximately
1 h.
7.8 Open the bottle and decant the contents (except for the copper specimen) into a 125 mL separatory funnel. Allow the layers
to separate and remove the aqueous layer to a beaker (Note 2). Wash the oil layer with 25 mL portions of distilled water, repeating
until the washings are neutral to litmus paper. Save the combined water washings. Dry the washed fluid with anhydrous sodium
sulfate or by vacuum dehydration (Note 3), or both. Filter the fluid through filter paper to remove the sodium sulfate solids.
NOTE 2—For water-containing fluids, there will be no separation, and so this step should be bypassed. Certain other fluids may emulsify with water and
not separate during this step. In either of these cases, no determination of water acidity will be conducted and a remark should be inserted into the test
report to this effect. If the fluid sample is heavier than water, drain the fluid from the separatory funnel, remove the water wash, and return the fluid to
the separatory funnel for repeated water washes.
NOTE 3—Mechanical stirring for 1 h with the anhydrous sodium sulfate dries the fluid efficiently. Add sufficient sodium sulfate with swirling until it no
longer forms clumps in the fluid.
7.9 Wash the oil layer with 25 mL portions of distilled water (inverting the separatory funnel several times to allow for sufficient
washing), repeating until the washings have the same pH as the distilled water, but perform no more than five washes (for most
samples, three are adequate). Add these water washes to the beaker from 7.8 and set aside for the water acidity determination in
7.12. Dry the washed fluid with anhydrous sodium sulfate or by vacuum dehydration (Note 3), or both.
NOTE 3—Mechanical stirring for 1 h with the anhydrous sodium sulfate dries the fluid efficiently. Add sufficient sodium sulfate with swirling until it no
longer forms clumps in the fluid.
7.10 Determine the After stirring, allow the fluid to stand 1 h so the sodium sulfate solids can settle. The fluid may be hazy at this
point, but if no visible solids are present, filtration is not necessary. Remove a sample (either by decantation or by using a pipet),
being careful that no solids are transferred, and determine the total acid number of the fluid in accordance with the same test
method that was used in 7.2. If solids have not settled enough to allow removal of a solid-free sample, filter the material through
filter paper to remove the solids and determine the total acid number of the filtered fluid in accordance with Test Methodthe same
D974test method that was used in 7.2. The acid number of the filtereddried fluid is compared to that of the original fluid
(determined in 7.2) and the change recorded.
7.11 Rinse the copper test specimen and beverage bottle with distilled water and n-heptane into the combined water washes (in
the beaker from 7.8) and then returntransfer to the separatory funnel. Separate the layers and wash the Wash the aqueous phase
with one 50 mL portion of n-heptane. Inversion of the separatory funnel several times allows for sufficient washing. Allow the
layers to separate.
7.12 Transfer the water entire aqueous layer to an EhrlenmeyerErlenmeyer flask. Determine total acidity by adding 1.0 mL of
phenolphthalein solution and titrating rapidly with 0.1 N KOH solution to the appearance of a pink phenolphthalein end point
which persists for 15 s. (Occasionally the solution will turn pink when the phenolphthalein is added. In that case, no titration or
calculation is necessary and water acidity should be reported as zero.) Calculate the water layer acidity as follows:
Total Acidity, mg KOH 5 A 2 B N 356,100 mg/Eq 1 L/1000 mL (1)
@~ ! # ~ !
D2619 − 21
where:
A = KOH solution required for titration of the sample, mL,
B = KOH solution required for titration of the blank, mL, and
N = normality of KOH solution.
On occasion, a test fluid may contain relatively large amounts of h
...