Engineering Understanding ASTM

Understanding ASTM

Understanding ASTM D2000 specifications

ASTM D2000 is a published specification that provides buyers and suppliers with a standard way to describe elastomer materials, using a ‘line call-out’ designation.

By understanding the ASTM D2000 structure, we can determine the important elements of the elastomer in question. These elements include:

  • Standards
  • Year Last Revised
  • Units of Measure
  • Grade
  • Type and Class
  • Hardness (Durometer)
  • Tensile Strength
  • Additional Requirement Suffixes

For the purpose of understanding ASTM D2000 specifications, we will refer to the following example:

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Standards

The standard in use. In specifying rubber products, this will be ASTM D2000.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Year Last Revised

A two digit code specifying the year that the standard was last revised. In our example, this value is 03.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Units of Measure

The units of measure used to report the test results. This will be either the inclusion of the letter M for metric units, or it will be left blank for English units of measure. In our example, the M is included.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Grade

The grade of the elastomer, indicates the level of test requirements to be applied. A grade of 1 indicates that only basic requirements are necessary, and grades of 2-9 define additional test requirements. In our example, this value is 2.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Type and Class

ASTM D2000 categorizes elastomer material types based on temperature resistance, and requires that they meet the following requirements after 70 hours, 100DC of heat aging at various temperatures, depending on the type.

Change in tensile strength: ±30%

Change in elongation: -50% max

Change in hardness: ±15 points

Class is used to differentiate materials on the basis their resistance to being immersed for 70 hours in IRM 903 Oil.

These tables show the letter designations for type and class:

The table below shows the most common polymer used for the given type / class:

ASTM D2000 SAE J200
Material Designation
(Type and Class)

Type of Polymer most often Used

AA

Natural rubber, Reclaimed rubber, SBR, Butyl,  EP Polybutadiene, Polyisoprene

BA

High temperature SBR and butyl compounds

BC

Chloroprene polymers (neoprene)

BE

Chloroprene polymers (neoprene)

BF

NBR polymers

BG

NBR polymers

BK

Organic dihalide polymers (Thickol), NBR

CA

Ethylene propylene

CE

Chlorosulfonated polyethylene (Hypalon)

CH

NBR Polymers

DF

Polyacrylic (butyl-acrylate type)

DH

Polyacrylic polymers, HNBR

EE

AEM, (Vamac)

FC

Silicones (high strength)

FE

Silicones

FK

Fluorinated silicones

GE

Silicones

HK

Fluorinated elastomers (Viton®)

KK

Perfluroroelastomers

In our example, the type is B and the class is G.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Hardness (Durometer)

The hardness of the material indicating the durometer range in Shore A units, ± 5 durometer. The call-out value is multiplied by 10 to get the actual value of the elastomer. In our example, the hardness is 70 ± 5 durometer.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Tensile Strength

The next two digits indicate the elastomer’s minimum tensile strength. This will be measured in MPa for metric units, and in psi for English units. In our example, the minimum tensile strength is 17 MPa.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

Additional Requirement Suffixes

The remaining part of the ASTM D2000 specification consists of suffix requirements, which are used when the basic requirements for a particular type and class of elastomer material are not sufficient to achieve the desired properties in the finished product.

The first letter of the suffix identifies the required test, as shown in the following table:

Suffix

Required Test

A

Heat Resistance

B

Compression Set

C

Ozone or Weather Resistance

D

Compression-Deflection Resistance

EA

Water Resistance

EF

Fuel Resistance

EO

Oil and Lubricant Resistance

F

Low Temperature Resistance

G

Tear Resistance

H

Flex Resistance

J

Abrasion Resistance

K

Adhesion

M

Flammability Resistance

N

Impact Resistance

P

Staining Resistance

R

Resilience

For each of the suffixes, the starting letter(s) are followed by numbers. The first number specifies the test method to be used, and the duration of that test. The second number indicates the testing temperature.

Depending on your specific application, you may need to use several of the suffix requirements to provide the exact compound that is desired.

In our example, the first letter ‘B’ of the first suffix indicates a Compression Set requirement, and the ‘14’ indicates the Test Methods D 395, Method B, max, %, 22 h at 100°C.

ASTM D2000 03 M2 BG 717 B14 EO14 EO34 F17

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