ASTM B406-96(2005)
(Test Method)Standard Test Method for Transverse Rupture Strength of Cemented Carbides
Standard Test Method for Transverse Rupture Strength of Cemented Carbides
SIGNIFICANCE AND USE
This test method is used as a means of determining the quality of cemented carbide grade powders by measuring their sintered strength. It is performed on test specimens prepared to specified shape, dimensions, and surface finish; test specimens may be prepared from finished parts if size permits. There is no known standard material for this test method. The transverse rupture strength of cemented carbides is not a design value.
3.1.1 Most commercial cemented carbides have mechanical behavior that is best classified as brittle (negligible ductility). Fracture strengths are dependent on internal or surface flaws. Examples of incoherent internal flaws are macropores, Type B porosity (see Test Method B 276), and inclusions of foreign particles. Such flaws are randomly distributed spatially and in size within the sintered material. This imparts a statistical nature to any transverse rupture strength measurement.
3.1.2 The stress distribution in a beam in three-point loading is non-uniform. It increases linearly along the span to a maximum at the center, and varies linearly through any section from compression on the top to tension on the bottom. The maximum tensile stress therefore occurs at center span in the bottom most fibers of the sample, and is defined as the transverse rupture strength at failure. Failure is initiated at a random flaw site, which is most probably not coincident with the maximum stress. This imparts an additional statistical nature to transverse rupture strength measurements.
SCOPE
1.1 This test method covers the determination of the transverse rupture strength of cemented carbides.
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI values in parentheses are provided for information only.
1.3 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:B406–96 (Reapproved 2005)
Standard Test Method for
Transverse Rupture Strength of Cemented Carbides
This standard is issued under the fixed designation B406; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope Examples of incoherent internal flaws are macropores, Type B
2 porosity (see Test Method B276), and inclusions of foreign
1.1 This test method covers the determination of the
particles. Such flaws are randomly distributed spatially and in
transverse rupture strength of cemented carbides.
size within the sintered material. This imparts a statistical
1.2 The values stated in inch-pound units are to be regarded
nature to any transverse rupture strength measurement.
as the standard. The SI values in parentheses are provided for
3.1.2 Thestressdistributioninabeaminthree-pointloading
information only.
is non-uniform. It increases linearly along the span to a
1.3 This standard does not purport to address the safety
maximum at the center, and varies linearly through any section
concerns, if any, associated with its use. It is the responsibility
from compression on the top to tension on the bottom. The
of the user of this standard to establish appropriate safety and
maximum tensile stress therefore occurs at center span in the
health practices and determine the applicability of regulatory
bottom most fibers of the sample, and is defined as the
limitations prior to use.
transverse rupture strength at failure. Failure is initiated at a
2. Referenced Documents
random flaw site, which is most probably not coincident with
the maximum stress. This imparts an additional statistical
2.1 ASTM Standards:
nature to transverse rupture strength measurements.
B276 Test Method for Apparent Porosity in Cemented
Carbides
4. Apparatus
2.2 ISO Standard:
4.1 Either a specially adapted machine for applying the load
ISO-3327 Hardmetals—Determination of Transverse Rup-
or a special fixture suitable for use with a conventional
ture Strength
load-applying machine may be used. In either case, the
3. Significance and Use
apparatus shall have the following parts:
4.1.1 Two ground-cemented-carbide cylinders 0.250 6
3.1 This test method is used as a means of determining the
0.001 in. (6.35 6 0.02 mm) in diameter, at least 0.500 in. (13
quality of cemented carbide grade powders by measuring their
mm) in length with the long axes parallel, and center to center
sintered strength. It is performed on test specimens prepared to
spacing of 0.563 6 0.005 in. (14.3 6 0.1 mm).
specified shape, dimensions, and surface finish; test specimens
4.1.2 Amovablemember(freetomovesubstantiallyonlyin
maybepreparedfromfinishedpartsifsizepermits.Thereisno
a line perpendicular to the plane established by the axes of the
known standard material for this test method. The transverse
two cylinders) containing a 0.4 6 0.05-in. (10 6 1.3-mm)
rupture strength of cemented carbides is not a design value.
cemented-tungsten-carbide ball or a ground-cemented-carbide
3.1.1 Most commercial cemented carbides have mechanical
cylinder of the same dimensions as, and with axis parallel to,
behavior that is best classified as brittle (negligible ductility).
those of the two previously mentioned cylinders (see 4.1.1).
Fracture strengths are dependent on internal or surface flaws.
This ball or cylinder shall be so positioned that movements of
the member will cause the ball or cylinder to contact a
This test method is under the jurisdiction of ASTM Committee B09 on Metal
specimen placed on the two lower cylinders at the midpoint of
Powders and Metal Powder Products and is the direct responsibility of Subcom-
the span between them.
mittee B09.06 on Cemented Carbides.
4.1.3 The apparatus shall be so constructed that the appli-
Current edition approved Oct. 1, 2005. Published October 2005. Originally
approved in 1963. Last previous edition approved in 2000 as B406 – 96 (2000).
cation of a sufficient load to the movable member to effect
DOI: 10.1520/B0406-96R05.
breaking of a specimen will not cause appreciable deflection of
This test method is comparable to ISO-3327.
the line of movement of the movable member and the plane
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM established by the two fixed cylinders. The apparatus shall be
Standards volume information, refer to the standard’s Document Summary page on
capable of applying sufficient load to break the specimen. The
the ASTM website.
apparatus shall be capable of registering the load required
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B406–96 (2005)
(within 61 % of the load) to break the specimen. The 7.3 Perform all tests at room temperature but not lower than
cemented-tungsten-carbide ball and cylinders shall not show 65°F (18°C).
permanent deformation after use. 7.4 Five specimens shall be tested.
8. Calculation
5. Specimen Size
8.1 Calculat
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