ASTM D7216 Standard Test Method for Determining Automotive Engine Oil Compatibility with Typical Seal Elastomers
6.1 The testing equipment as specified in Test Methods D412, D471, D2240, and D5662 is required for the use of this test method.
6.2 Balance - Use any commercially available balance capable of weighing to the nearest 0.1 mg. Equip the balance with a suspension hook and a platform to locate a hydrostatic-weighing beaker above the balance pan.
6.2.1 Calibration - Calibrate the balance annually as described in Test Method D5662.
6.3 Hardness Durometer A - See Test Method D2240. Use a stand–mounted Durometer.
6.3.1 Calibration - Calibrate the hardness Durometer annually as described in Test Method D2240. Use an outside source, with standards traceable to the National Institute for Standards Technology (NIST), for annual calibration. Perform checks with internal standards weekly. Checks with internal standards shall be within +/- 3 points. Calibrate internal standards annually, using an outside source, with standards traceable to NIST.
6.4 Tension Testing Machine - See the appropriate sections of Test Method D412. The rate of grip separation for the tension testing shall be 8.5 +/- 0.8 mm/s (0.33 +/- 0.3 in./s).
6.4.1 Calibration - Using an outside source, calibrate the tension testing machine annually, as described in Test Method D412, using standards traceable to NIST.
6.5 Glass Tubes - Preferably of borosilicate glass, having an outside diameter of 38 mm (1.5 in.) and an overall length of 300 mm (12 in.). Fit each tube loosely with an inert sealing device (such as a cork stopper covered with aluminum foil) that will not contaminate the test oil.
6.6 Hanger Wire - Stainless steel, about 0.5 mm (0.020 in.) diameter, having a suitably sized eye at one end and a hook with an approximately 8-mm (0.31-in.) gape at the other, to suspend the elastomer test specimens when measuring their mass in water.
6.7 Specimen Suspension Wire - Stainless steel, about 0.8 to 1 mm (0.03 to 0.04 in.) diameter to the shape and dimensions shown in Fig. 1, to hold the elastomer test specimens submerged in the immersion oil. (The specimens are attached to the suspension wire which is hung over the edge of the glass tube and held in place by the stopper as shown in Fig. 2.)
6.8 Heated Immersion Test Bath or Block - Capable of maintaining the test oil in the glass tube to within +/- 1°C of the test temperature. The immersion test bath or block shall contain a rack or holes that will accept the glass tubes specified in 6.5 and hold them in a vertical position.
6.9 Die for Cutting Dumbbells - Use Die C as specified in Test Method D412.
7. Reference Materials
7.1 Reference Oil - The reference oil is maintained and distributed by the (TMC). The reference oil designation is TMC 1006-1. In order to receive this reference oil, individual laboratories shall agree to furnish the TMC with immersion test results obtained with the reference oil.
7.1.1 The TMC is responsible for managing a system that ensures the performance and formulation consistency of the reference oil. Store the reference oil in locations where the ambient temperature does not exceed 32°C. Under these conditions the shelf life of the reference oil is five years. In some circumstances, however, the TMC may specify a shelf life longer than five years. In such cases, they will use documented analysis procedures to justify the longer shelf life.
7.2 Purity of Water - Unless otherwise indicated, references to water shall be understood to mean water conforming to Specification D1193 Type III deionized water or water of equivalent purity.
7.3 Wetting Agent Solution - 0.1 % sodium dioctyl sulfosuccinate, made by a suitable dilution of concentrated solution with reagent water. (Warning - Eye irritant.)
7.4 Reference Seal Elastomers - Obtain cured prepared sheets of the reference seal elastomers from the Parts Distributor (PD). The sheets are at least 152 by 152 mm (6 by 6 in.) and have a uniform thickness of 2 +/- 0.1 mm (0.079 +/- 0.004 in.). The specific reference elastomers described in this test method are a fluoroelastomer (FKM), a polyacrylate material (ACM), a silicone rubber (VMQ), a nitrile rubber (NBR), and a VAMAC (MAC).
NOTE 4 - Elastomer sheets received from the PD are numbered in the following format: [type] X. Type = the elastomer type (for example, FKM, ACM, VMQ, NBR, or MAC), and X = batch number for the particular formulation.
7.4.1 Table A1.1 specifies the formulations for the reference elastomers listed in 7.4. Some typical properties of the reference elastomers are also shown in Table A1.1; these data are provided for information purposes only.
7.4.2 The PD is responsible for maintaining the numbering and tracking system for the reference elastomers and for managing the procurement of elastomers that meet the specifications of this standard. Certain specific information concerning these reference materials is available only to the PD. This information is used to ensure batch-to-batch consistency.
7.4.3 Store the reference elastomers in a location shielded from light, where the relative humidity is in the range of 40 to 55 % and the temperature in the range of 10 to 25°C. Under these conditions the shelf life of the reference elastomers is three years from the date of cure provided by the PD. Do not use any elastomer with a seal cure date older than three years.