A major challenge for companies sourcing and buying automotive rubber products is to accurately specify the desired material properties to suppliers. Communicating desired material properties fully and accurately gives buyers the confidence that suppliers will be able to supply the rubber compound that best meets their specific needs.

The Society of Automotive Engineers (SAE) introduced a standard (SAE J200 – Classification System for Rubber Materials) to provide engineers with a classification system for commercially available rubber materials and to provide a simple designation method for these materials, called the “Line call-out.” An equivalent standard to J200 was subsequently developed by the American Society of Testing and Materials (ASTM); this is the ASTM D2000 standard (ASTM D2000 – Standard Classification System for Rubber Products in Automotive Applications). The J200 standard is now obsolete and the ASTM D2000 standard is now the de facto standard for line call-outs used in the marketplace.

The ASTM D2000 standard provides a common language through which buyers may communicate their material requirements to suppliers of automotive rubber products. Specifying desired material characteristics and requirements through ASTM D2000 affords suppliers like CRGI the opportunity to choose and supply the rubber compound which is most appropriate for a particular application (i.e., under-hood, diesel, exterior vehicle, interior, etc.).  Most importantly, through ASTM D2000, suppliers are able to help buyers meet cost targets without compromising quality and performance: the supplier can select the most economical rubber compound which fully satisfies the specified line call-out.

Buyers should familiarize themselves with how D2000 line call-outs work in practice. At the most basic level, both standards begin by classifying rubber materials by both Type (heat resistance) and Class (oil resistance). From there, a line call-out becomes progressively more detailed as it further defines the specific material properties desired for an automotive rubber product.

Here is an example of a typical D2000 line call-out:

ASTM D2000-12 M3 CA 7 10 A25 B35 C32 F17 G21 Z1, Z1= {Desired result, test method}

This line call-out breaks down as follows:

“ASTM D2000” is the reference number for the standard used in the line call-out. “-12” indicates the version year of the standard; the latest version should always be used.

“M3” designates the units of measure and the material grade number. “M” means metric units are to be used, and “3” designates the grade number of the rubber. The various rubber grades are shown in a table contained within the D2000 standard. The grade number designates instances where more extensive material tests are required. Any grade number other than 1 mandates additional requirements that are spelled out in the D2000 standard.

“CA” designates the material type and class. “C” indicates the type (resistance of the material to heat aging) and “A” indicates the class (oil resistance of the material as measured by volume and swell tests). Both type and class designations are drawn from tables contained within the D2000 standard. The type and class designations can be combined to specify the material type; for example, the type and class values in this example line-call out designate the material in this example line call-out as “ethylene propylene” (EPM, EPDM).

“7” designates the material hardness, or durometer. In this case, “7” is equal to a Shore A durometer of 70.

“10” designates the minimum material tensile strength. Since the units in this example are metric, “10” means a minimum tensile strength of 10MPa.

The remaining portion of the example line call-out is the so-called “suffix requirements.” The suffix requirements indicate any additional testing requirements needed to satisfy the specification callout. Each requirement is comprised of a suffix letter, calling out the property being tested, and the suffix numbers which call out the test method and test temperature.

In our line call-out example, the “A” in “A25” means that a heat resistance test is required. The “2” indicates that the test method is D965, while “5” indicates that the test temperature range is from -25°C to 125°C. The values for the suffix letters and numbers are contained within the D2000 standard. Thus, in our example, “B35” indicates a compression set test, “C32” an ozone resistance test, “F17” a low temperature test, and “G21” a tear resistance test. “Z1” is a suffix which allows an engineer to customize a line call-out outside the parameters of the specification. The “Z1” suffix  MUST be defined in the line call out as above. There are no limitations to the number of “Z” suffixes.

Canada Rubber Group Inc. (CRGI) has extensive experience in using the ASTM D2000 standard to provide automakers, and their supply chain, with the highest quality automotive rubber products. We know how to work with buyers who use the ASTM D2000 standard in procurement and avoid the pitfalls noted above. CRGI can help streamline your ASTM D2000 buying process and ensure that your application needs are fully understood and met, first time, every time. To find out how CRGI can help you with your automotive rubber product needs, contact our Automotive Sales Manager, Paul Carey at crg@canadarubbergroup.com.

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