ASTM C749 - 13

    Standard Test Method for Tensile Stress-Strain of Carbon and Graphite

    Active Standard ASTM C749 | Developed by Subcommittee: D02.F0

    Book of Standards Volume: 05.05


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    Significance and Use

    5.1 The round robin testing on which the precision and bias for this test method have been determined employed a range of graphites (see Table 2) whose grain sizes were of the order of 1 mil to 1/4 in. (0.0254 to 6.4 mm) and larger. This wide range of carbons and graphites can be tested with uniform gauge diameters with minimum parasitic stresses to provide quality data for use in engineering applications rather than simply for quality control. This test method can be easily adapted to elevated temperature testing of carbons and graphites without changing the specimen size or configuration by simply utilizing elevated temperature materials for the load train. This test method has been utilized for temperatures as high as 4352°F (2400°C). The design of the fixtures (Figs. 2-9 and Table 1) and description of the procedures are intended to bring about, on the average, parasitic stresses of less than 5 %. The specimens for the different graphites have been designed to ensure fracture within the gauge section commensurate with experienced variability in machining and testing care at different facilities. The constant gauge diameter permits rigorous analytical treatment.

    5.2 Carbon and graphite materials exhibit significant physical property differences within parent materials. Exact sampling patterns and grain orientations must be specified in order to make meaningful tensile strength comparisons. See also Test Methods C565.

    1. Scope

    1.1 This test method covers the testing of carbon and graphite in tension to obtain the tensile stress-strain behavior, to failure, from which the ultimate strength, the strain to failure, and the elastic moduli may be calculated as may be required for engineering applications. Table 2 lists suggested sizes of specimens that can be used in the tests.

    TABLE 1 List of Materials Shown in Fig. 2

    Assembly

    Item

    Quantity

    Name, Description, Material

    1A

    101

    2

    Crosshead attachment yoke—1 dia x 4 long—416 or 440 S.S.

    1/2 in. A grips B,C

    102

    2

    Chain—3/16  dia, 700 pound tensile limit, 10 links long—Carbon Steel

     

    103

    4

    Chain journal—9/16 dia x 1/2 long—416 or 440 S.S.D

     

    104

    4

    Pin—3/16 dia x 1—Std Dowel

     

    105

    2

    Grip attachment yoke—1 dia x 25/8 long—416 or 440 S.S.D

     

    106

    2

    Pin—1/4 shank dia with 1/2 dia x 3/4 long knurled head, total length
     21/2 , taper first half inch at 10°—416 or 440 S.S.D

     

    107

    2

    Grip sleeve—11/2  dia x 25/16 long—416 or 440 S.S.D

     

    108

    2

    Split sleeve—1 dia x 1 long—416 or 440 S.S.D

     

    109

    1

    Specimen—0.510 dia x 43/4 long—Carbon

     

    110

     

    Not Used

    1B

    . . .

    2

    Item 101—Crosshead attachment yoke

    3/4 in. A grips

    . . .

    2

    Item 102—Chain

     

    . . .

    4

    Item 103—Chain journal

     

    . . .

    4

    Item 104—Pin

     

    . . .

    2

    Item 105—Grip attachment yoke

     

    . . .

    2

    Item 106—Pin

     

    111

    2

    Grip sleeve—11/2 dia x 25/16 long—416 or 440 S.S.D

     

    112

    2

    Split sleeve—1 dia x 1 long—416 or 440 S.S.D

     

    113

    1

    Specimen—0.760 dia x 43/4 long—Carbon

     

    114

     

    Not Used

    1C

    115

    2

    Crosshead attachment yoke—11/2 dia x 4 long—416 or 440 S.S.D

    11/4 in. A grips

    116

    2

    Chain—3/8 dia, 5100 pound tensile limit, 10 links long—Carbon Steel

     

    117

    4

    Chain journal—5/8 dia x 5/8 long—416 or 440 S.S.D

     

    118

    4

    Pin—3/8 dia x 11/2 long—Std Dowel

     

    119

    2

    Grip attachment yoke—11/2 dia x 25/8 long—416 or 440 S.S.D

     

    120

    2

    Pin—1/2 shank dia with 3/4 dia x 3/4 long knurled head, total length
     41/4 , taper first half inch at 10°—416 or 440 S.S.D

     

    121

    2

    Grip sleeve—17/8 dia x 35/8 long—416 or 440 S.S.D

     

    122

    2

    Split sleeve—11/2 dia x 21/4 long—416 or 440 S.S.D

     

    123

    1

    Specimen—11/4 dia x 93/4 long—Carbon

     

    124

     

    Not Used

    1D

    . . .

    2

    Item 115—Crosshead attachment yoke

    2 in. A grips

    . . .

    2

    Item 116—Chain

     

    . . .

    4

    Item 117—Chain journal

     

    . . .

    4

    Item 118—Pin

     

    125

    2

    Grip attachment yoke—21/4 dia x 25/8 long—416 or 440 S.S.D

     

    126

    2

    Pin—1/2 shank dia with 3/4 dia x 3/4 long knurled head, total length
     41/4 , taper first half inch at 10°—416 or 440 S.S.D

     

    127

    2

    Grip sleeve—23/4 dia x 51/2 long—416 or 440 S.S.D

     

    128

    2

    Split sleeve—21/4 dia x 4 long—416 or 440 S.S.D

     

    129

    1

    Specimen—2.000 dia x 143/8 long—Carbon

     

    130

     

    Not Used

    A 1 in. is equal to 25.4 mm.
    B Preload chain to yield using a load time recording.
    C Commercially available.
    D Or alternative high strength stainless steel.
    TABLE 2 Sample Sizes Used in Round-Robin Tests (Suggested Specimen Size)A

    MaterialB

    Max Grain Size, in.

    Sample, in.

    Specimen
    Size, in.

    Recommended
    Shank and
    Maximum Gauge,
    in.

    AXM-50

    0.001

    5 by 5 by 5, molded

    1/2 by 0.200C

    1/2 by 3/16 

     

     

     

     

    3/4 by 1/4 

    9326

    0.001

    20 by 10 by 2, molded

    1/2 by 1/4 

     

     

     

     

    3/4 by 0.3

     

     

     

     

    1/2 by 3/16 C

     

     

     

     

     

    1/2 by 3/16 

     

     

     

     

    3/4 by 1/4 

    9326A

    0.001

    20 by 10 by 2, molded

    1/2 by 1/4 

    1/2 by 3/16 

     

     

     

    3/4 by 3/8 

     

     

     

     

    3/4 by 0.3

    3/4 by 0.3

     

     

     

    3/4 by 3/8 

     

     ATJ

    0.006

    13, rounds, molded

    1/2 by 1/4 

    1/2 by 1/4 

     

     

     

    3/4 by 3/8 

    3/4 by 1/4 

     

     

     

    3/4 by 3/8 

    3/4 by 1/4 

     

     

     

    3/4 by 3/8 

     

    HLM

    0.033

    molded, 10 by 18 by 25

    1/2 by 1/4 

    3/4 by 3/8 

     

     

     

    3/4 by 3/8 

     

     

     

     

    3/4 by 3/8 

     

     

     

     

    3/4 by 3/8 

     

     CS

    0.030

    10, rounds, extruded

    2 by 1

     

     

     

     

    3/4 by 3/8 

    3/4 by 3/8 

     

     

     

    1/2 by 1/4 

     

     

     

     

    1/2 by 1/4 

     

    C565 Test Methods for Tension Testing of Carbon and Graphite Mechanical Materials

    C709 Terminology Relating to Manufactured Carbon and Graphite

    E4 Practices for Force Verification of Testing Machines

    E6 Terminology Relating to Methods of Mechanical Testing

    E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods

    E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method


    ICS Code

    ICS Number Code 71.060.10 (Chemical elements)

    UNSPSC Code

    UNSPSC Code 11101507(Graphite)


    DOI: 10.1520/C0749

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