ASTM D 2000 • SAE J 200
Standard Classification System for Rubber Products in Automotive Applications
This classification system tabulates the properties of vulcanized rubber materials that are intended for, but not limited to, use in rubber products for automotive applications. The purpose of the classification system is to provide guidance in the selection of practical, commercially available rubber materials, and to provide a method for specifying these materials by the use of a simple “line call-out” designation.
Type and Class
Rubber materials are classified on the basis of type (heat resistance) and class (oil resistance). Type and class are indicated by letter designations as shown below:
Type is based on changes in tensile strength of not more than ±30%, elongation of not more than − 50%, and hardness of not more than ±15 points after heat aging for 70 hours at a temperature from the table above.
Class is based on the resistance of the material to swelling in ASTM Oil No. 3 after 70 hour immersion at a temperature determined from the same table. Limits of swelling for each class are shown above.
The letter designations are followed by a three-digit number to specify the hardness and the tensile strength—for example, 605. The first digit indicates durometer hardness, for example, 5 for 50 ± 5, 6 for 60 ± 5. The next two digits indicate the minimum tensile strength—for example, 05 for 5 MPa, 14 for 14 MPa.
Since the basic requirements do not always describe sufficiently all the necessary qualities, provision is made for deviation or adding requirements through a system of prefix grade numbers.
The suffix letters together with their meaning are listed below. Each suffix letter is followed by two suffix numbers. The first suffix number indicates the test method; the second suffix number indicates the temperature of test.
A “line call-out,” which is a specification, contains the documents names, the prefix letter M, the grade number, the material designation (type and class), and the hardness and tensile strength, followed by the appropriate suffix requirements.