temperature of 150°C (the upper limit of oil stability) shall be
used. Limits of swelling for each class are shown in
4.4.1 ASTM No. 1, No. 2, and No. 3 Oils have been
replaced by IRM 901, 902, and 903 Oils, respectively, under
Practice
These oils are similar but not identical to
ASTM No. 1, No. 2, and No. 3 Oils.
4.4.2 Substitutability of IRM 901, 902, and 903 Oils for
ASTM No. 1, No. 2, and No. 3 Oils has not been established,
as their swelling characteristics are different and may affect
compound classification.
N
OTE
4—The selection of type based on heat resistance is understood to
be indicative of the inherent heat resistance that can be normally expected
from commercial compositions. Likewise, choice of class is based on the
range of volume swell normally expected from such commercial compo-
sitions as established by type. The fact that a type and class of material is
listed in
, under Basic Requirements, indicates that materials that
meet these requirements for heat and oil resistance are commercially
available.
4.5 The letter designations shall always be followed by a
three-digit number to specify the hardness and the tensile
strength—for example, 505. The first digit indicates durometer
hardness, Type A, for example, 5 for 50 6 5, 6 for 60 6 5. The
next two digits indicate the minimum tensile strength—for
example, 05 for 5 MPa, 14 for 14 MPa. Correlation of
available materials for desired hardness and tensile strength is
obtained through the elongation values in
. See
5. Grade Numbers, Suffix Letters, and Number
5.1 Grade Numbers—Since the basic requirements do not
always describe sufficiently all the necessary qualities, provi-
sion is made for deviation or adding requirements through a
system of prefix grade numbers. Grade No. 1 indicates that
only the basic requirements are compulsory, and no suffix
requirements are permitted. Grades other than No. 1 are used
for expressing deviation or additional requirements and are
listed as “Available Suffix Grade Numbers” in the last column
under Basic Requirements in
. A grade number is
written as a material prefix number preceding the letters for
type and class (see
). Grade No. 1 is always an available
suffix grade number, and thus is not referenced in the last
column of each basic requirement table.
5.2 Suffıx Letters—The suffix letters that may be used,
together with their meaning, appear in
5.3 Suffıx Numbers—Each suffix letter should preferably be
followed by two suffix numbers (see
in
). The first
suffıx number always indicates the test method; time of test is
part of the method and is taken from the listings in
. The
second suffıx number, if used, always indicates the temperature
of test and is taken from
. Where three-digit numbers
are required, they are separated by a dash—for example: –10;
B4–10; F1–11.
6. Composition and Manufacture
6.1 This classification system is predicated upon materials
furnished under a specification based thereon being manufac-
tured from natural rubber, reclaimed rubber, synthetic rubber,
alone or in combination, together with added compounding
ingredients of such nature and quantity as to produce vulcani-
zates that comply with the specified requirements. All materials
and workmanship shall be in accordance with good commer-
cial practice, and the resulting product shall be free of porous
areas, weak sections, bubbles, foreign matter, or other defects
affecting serviceability.
6.2 Color—With the exception of FC, FE, FK, and GE
materials, the values in the material tables are based on black
compounds and comparable values may not be available in
color.
7. Basic Requirements
7.1 The basic requirements for physical properties specified
in
are based on values obtained from standard
laboratory test specimens prepared and tested in accordance
with the applicable ASTM test methods. Test results from
specimens prepared from finished products may not duplicate
values obtained from standard test specimens.
N
OTE
5—When standard test specimens are cut from finished parts in
accordance with Practice
, a deviation to the extent of 10 % (on
tensile strength and elongation values only) is permissible when agreed
upon by the purchaser and the supplier. This deviation is permissible only
because of the recognized effects of knitting, grain, and buffing on the
material when test specimens are prepared from finished parts and tested
for tensile strength and elongation. 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.
7.2 The available materials are listed in the appropriate
material section of the table, giving each hardness and tensile
strength with its appropriate elongation value. Also, there is a
repetition of the values for the basic heat and oil aging
requirements for the material resulting from the assignment of
type and class. In addition, values for compression set, nor-
mally a basic requirement to ensure proper vulcanization, are
specified.
7.3 Unless a suffix requirement is used to override an
existing basic requirement, the basic requirement applies.
TABLE 5 ASTM Test Methods
Basic Requirements
and First Suffix No.
Basic
1
2
3
4
5
6
7
8
9
Requirement or
Suffix Letter
Tensile Strength,
Elongation
die C
...
...
...
...
...
...
...
...
...
3
Tensile values are shown as pounds per square inch in
for information
only.
D 2000 – 08
3
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