These specifications cover vulcanized elastomer compounds of natural rubber, reclaimed rubber, synthetic rubber, or rubberlike materials, alone or in combination, which are intended for use in manufacturing products for automotive applications. Compounds for tires, inner tubes, sponge rubber, hard rubber, belts, hose, mats, and insulated wire and cable are not included.

The compounds listed in

Tables 1 to 6

are of three types grouped in six classifications, based primarily on physical properties, which are prescribed in the tables. These values together with any additional requirements indicated by suffix letters in the grade designations as described in section, Types, Classes, and Grades of Compounds, define the properties of the compounds after vulcanization. These values apply to test specimens obtained from standard laboratory test slabs or blocks prepared in accordance with procedures described in the applicable ASTM methods.

test results from finished products may not duplicate the values obtained from standard test specimens

. When differences due to the method of processing or to the difficulty in obtaining suitable test specimens from the finished part arise, the purchaser and the supplier may agree on acceptable deviations. This can be done by comparing results of standard test specimens with those obtained on actual parts.

Since it is recognized that basic requirements used mainly to classify compounds do not sufficiently describe some compositions, provision is made for added requirements which are indicated by suitable suffixes to the grade numbers. When the compounds may be used for purposes where the requirements are too specific to be prescribed in general specifications, it is advisable for the purchaser to consult the supplier to secure adjustment of the properties to suit the actual operations to which the material is to be subjected.

In case of conflict between the provisions of these general specifications and those of detailed specifications for a particular product, the latter shall take precedence.

These automotive classified compounds will serve many of the needs of other industries, even as SAE numbered steels are used. It must be remembered, however, that these specifications are subject to revision when required by automotive needs, and there is no assurance that the change will be acceptable to all other users.

A key chart for reference use contains pertinent information and an example illustrating the use of these specifications.