ASTM D6546-23
Standard Test Methods for and Suggested Limits for Determining Compatibility of Elastomer Seals for Industrial Hydraulic Fluid Applications
- Standard No.
- ASTM D6546-23
- Release Date
- 2023
- Published By
- American Society for Testing and Materials (ASTM)
- Latest
- ASTM D6546-23
- Scope
- 1.1 These test methods cover the procedure for measuring physical properties of elastomer seals in the form of O-rings after exposure to industrial hydraulic fluids and thermal aging. The measured properties are then compared to the physical properties of elastomer seals that have not been exposed to the industrial hydraulic fluids and thermal aging. The changes in these properties form a basis for assessing compatibility when these changes are compared against the suggested limits in Table 1. 1.2 While these test methods involve the use of O-rings, they can also be used to evaluate the compatibility of the elastomeric compounds of specialty seals with industrial hydraulic fluids and their resistance to thermal aging. The compounds can be molded into O-rings for evaluation purposes. 1.3 These test methods provide procedures for exposing O-ring test specimens to industrial hydraulic fluids under definite conditions of temperature and time. The resulting deterioration of the O-ring material is determined by comparing the changes in work function, hardness, physical properties, compression set, and seal volume after immersion in the test fluid to the pre-immersion values. 1.4 The values stated in SI units are to be regarded as the standard. 1.4.1 Exception—The values given in parentheses are for information only. 1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 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. A1.1 Scope A1.1.1 This test method covers the determination of the cure state of elastomers by DSC. It is based on Test Method D5028.This test method is applicable to elastomers with adequate vulcanizers. The normal operating temperature range is from room temperature to 250 °C (482 °F), but not limited to such. All elastomers should be fully cured. D6546 − 23 6 A1.2 Apparatus A1.2.1 Differential Scanning Calorimeter, capable of heating a test specimen and a reference material at a controlled rate up to at least 20 °C (68 °F) per minute and of automatically recording the differential heat flow. A1.2.2 Specimen Holders, composed of clean aluminum or other high thermal conductivity material. Specimen holders may be of the open, covered, or sealed type. A1.2.3 Nitrogen, or other inert purge gas supply. A1.2.4 Flowmeter, for purge gas. A1.2.5 Recording Charts, for temperature recording apparatus with suitable graduation for measurements of energy differential or time. A1.3 Calibration A1.3.1 Calibrate the apparatus in accordance with the manufacturer’s instructions with appropriate standard reference materials at the same heating rate to be used for samples. For the temperature range of this procedure, indium with a melting point of 156 °C (312.8 °F) may be used. A1.4 Procedure A1.4.1 Cured Elastomer Part: A1.4.1.1 Randomly select a cured elastomer part and randomly choose a small section of the part from its center, and weigh out 76.54 mg to 153.08 mg of the section. A1.4.1.2 Crimp a flat metal cover against the pan with the sample sandwiched between them to ensure good heat transfer. Place the sample in the DSC cell. A1.4.1.3 Intimate thermal contact between the sample and the thermocouple is essential for reproducible results. A1.4.1.4 Purge the cell with nitrogen at 50 cc ⁄min to 100 cc ⁄min (3.06 in.3 /min to 6.10 in.3 /min) gas flow rate. A1.4.1.5 Heat the sample at a rate of 10 °C ⁄min (50 °F ⁄min) under nitrogen atmosphere from ambient to a temperature high enough to achieve the entire exothermic curing curve. Record the thermogram. A1.4.1.6 Measure the heat of reaction (∆HR), the shaded area of Fig. A1.1 (see Figs. A1.1 and A1.2). A1.5 Calculation A1.5.1 Use the resulting thermogram to determine the exothermic heat of the curing reaction (∆HR) of the crosslinking reaction. This is used to indicate the extent of cure. A fully cured material shall exhibit a ∆HR of 0 cal/g (0 Btu/lb). Fig. A1.2 depicts a fully cured material. A1.5.2 If the sample exhibits a ∆HR of 0 cal/g (0 Btu/lb), the sample is fully cured. If the sample exhibits a ∆HR of greater than 0 cal/g (0 Btu/lb) (see Fig. A1.1), run a duplicate sample. If the duplicate sample yields a ∆HR of 0 cal/g (0 Btu ⁄lb), run a third sample such that two independent runs are in agreement. If the duplicate sample yields a ∆HR greater than 0 cal/g (0 Btu/lb), the elastomer part is not fully cured and processing is not consistent. A1.6 Report A1.6.1 Report the following information: A1.6.1.1 Sample identification including compound and batch inside diameter and mass, FIG. A1.1 Thermogram Representative of an Uncured Elastomer D6546 − 23 7 A1.6.1.2 Heating rate and purge gas flowrate, A1.6.1.3 Value of ∆HR, A1.6.1.4 Date of testing, and A1.6.1.5 Copies of the actual DSC curves. A1.7 Precision and Bias A1.7.1 Since this test method is designed to determine whether a sample is fully cured or not, the heat of reaction (∆HR) is the value of interest. If the value of ∆HR is positive, then the sample is not fully cured. Calorimetric precision is normally 61 % and calorimetric accuracy is also 61 %, but fully cured materials have no exotherm. What is important in determining if a material is fully cured is the stability of the baseline because any positive value above baseline can be interpreted as an exotherm. Baseline noise for these types of instruments is 0.00431 cal (0.0000171 Btu). Baseline noise during a run can in effect create a positive indication. If the maximum baseline noise value is divided by the minimum sample mass, 76.54 mg, then a baseline maximum deviation of 0.0563 cal ⁄g can be expected. Therefore, any test value that ranged from 0 cal ⁄g to +0.0563 cal ⁄g would be equivalent to fully cured material. A2. SIZES OF O-RINGS USED IN TEST PROCEDURES A2.1 Table A2.1 lists the actual sizes of the O-rings used in the test methods. The sizes are in accordance with AS568A. FIG. A1.2 Thermogram Representative of a Fully Cured Elastomer D6546 − 23 8 SUMMARY OF CHANGES Subcommittee D02.N0 has identified the location of selected changes to this standard since the last issue (D6456 – 15) that may impact the use of this standard. (Approved July 1, 2023.) (1) Added Terminology D4175 to Sections 2 and 3. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585 (phone), 610-832-9555 (fax), or [email protected] (e-mail); or through the ASTM website (www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http://www.copyright.com/ TABLE A2.1 O-ring Sizes AS568A Designation Inside Diameter (in.) Cross Section, in. Inside Diameter (mm) Cross Section, mm -021 0.926 ± 0.009 0.070 ± 0.003 23.52 ± 0.23 1.78 ± 0.08 -120 0.987 ± 0.010 0.103 ± 0.003 25.07 ± 0.25 2.62 ± 0.08 -214 0.984 ± 0.010 0.139 ± 0.004 24.99 ± 0.25 3.53 ± 0.10 -320 1.100 ± 0.012 0.210 ± 0.005 27.94 ± 0.30 5.33 ± 0.13 D6546 − 23 9
ASTM D6546-23 Referenced Document
- ASTM D1414 Standard Test Methods for Rubber O-Rings
- ASTM D2000 Standard Classification System for Rubber Products in Automotive Applications
- ASTM D2240 Standard Test Method for Properties of Rubber &8212; Durometer Hardness*， 2024-04-21 Update
- ASTM D3677 Standard Test Methods for Rubber
- ASTM D3767 Standard Practice for Rubber-Measurement of Dimensions
- ASTM D395 Standard Test Methods for Rubber Property-Compression Set
- ASTM D412 Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers8212;Tension
- ASTM D4175 Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
- ASTM D471 Standard Test Method for Rubber Property-Effect of Liquids
- ASTM D5028 Standard Test Method for Curing Properties of Pultrusion Resins by Thermal Analysis
- ASTM E1131 Standard Test Method for Compositional Analysis by Thermogravimetry
ASTM D6546-23 history
- 2023 ASTM D6546-23 Standard Test Methods for and Suggested Limits for Determining Compatibility of Elastomer Seals for Industrial Hydraulic Fluid Applications
- 2015 ASTM D6546-15 Standard Test Methods for and Suggested Limits for Determining Compatibility of Elastomer Seals for Industrial Hydraulic Fluid Applications
- 2000 ASTM D6546-00(2010) Standard Test Methods for and Suggested Limits for Determining Compatibility of Elastomer Seals for Industrial Hydraulic Fluid Applications
- 2000 ASTM D6546-00(2005) Standard Test Methods for and Suggested Limits for Determining Compatibility of Elastomer Seals for Industrial Hydraulic Fluid Applications
- 2000 ASTM D6546-00 Standard Test Methods for and Suggested Limits for Determining Compatibility of Elastomer Seals for Industrial Hydraulic Fluid Applications
