ASTM F2328-05
(Test Method)Standard Test Method for Determining Decarburization and Carburization in Hardened and Tempered Threaded Steel Bolts, Screws and Studs
Standard Test Method for Determining Decarburization and Carburization in Hardened and Tempered Threaded Steel Bolts, Screws and Studs
SIGNIFICANCE AND USE
Decarburization and carburization are two surface conditions created, either intentionally or unintentionally, as with a pre-existing condition created during the rod rolling process, the rod/wire annealing process, or while heat treating threaded steel products. Too much of either will adversely affect the safety and performance of the threaded product. Therefore, limits have been established for three different product groups: the harder and greater the tensile strength of the product, the more susceptible to failure the product becomes if these limits are exceeded.
When testing to a particular product specification that lists the dimensions and microindentation data to be used, that data shall take precedence over the tables in this test method.
There are only two viable methods available to detect these deficiencies, either by the visual method or the microindentation method. Both methods are used for routine inspections when evaluations are conducted at a single location on the product sample.
4.3.1 Because an evaluation at a specific location may not be representative of the whole part, the referee method employs the microindentation method taken as an average of evaluations conducted on four adjacent threads. This procedure significantly reduces the random test variables when compared to testing on a single thread.
Specifying this test method does not specify or imply that testing shall be for either decarburization or carburization alone or for both conditions. When either test method is performed, both conditions will be apparent and shall be reported. For example, if an order is placed to test for decarburization and none is found, but the presence of carburization is detected, it shall be reported on the test report that carburization was found.
SCOPE
1.1 This test method covers procedures for measuring, classifying, and determining the presence of decarburization and carburization in the threaded section of hardened and tempered inch series steel bolts, screws, studs, and similar parts which have been heated to facilitate fabrication or to modify its mechanical properties. This test method is not intended to address products which are intentionally carburized to achieve specific results.
1.2 Two routine methods are described for measuring the limits of and determining the presence of decarburization or carburization-the optical method and the microindentation method 1. Either method is appropriate for routine examinations. The microindentation method 2 shall be considered the referee method.
1.3 For the purpose of these tests, there are three classes of hardened and tempered steel products for which specific measurements must be made with respect to their physical properties.
This standard does not purport to address all of 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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Standards Content (Sample)
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Designation: F2328 – 05
Standard Test Method for
Determining Decarburization and Carburization in Hardened
1
and Tempered Threaded Steel Bolts, Screws and Studs
This standard is issued under the fixed designation F2328; 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.
1. Scope 3.1.1 carburization—process or result of increasing the
carbon content of the surface layers of the steel fastener
1.1 This test method covers procedures for measuring,
product.
classifying, and determining the presence of decarburization
3.1.2 decarburization—in accordance with Terminology
and carburization in the threaded section of hardened and
F1789,isalossofcarbonfromthesurfacelayerofthefastener,
temperedinchseriessteelbolts,screws,studs,andsimilarparts
normally associated with heat treatment.
whichhavebeenheatedtofacilitatefabricationortomodifyits
3.1.3 gross decarburization—also known as complete de-
mechanical properties. This test method is not intended to
carburization, is characterized by a sufficient carbon loss to
address products which are intentionally carburized to achieve
show only clearly defined ferrite grains.
specific results.
3.1.4 partial decarburization—characterized as a loss of
1.2 Two routine methods are described for measuring the
carbon sufficient to cause a lighter shade of tempered marten-
limits of and determining the presence of decarburization or
site than that of the immediately adjacent base metal, but as
carburization—the optical method and the microindentation
being of insufficient carbon loss to show clearly defined ferrite
method 1. Either method is appropriate for routine examina-
grains.
tions. The microindentation method 2 shall be considered the
referee method.
4. Significance and Use
1.3 For the purpose of these tests, there are three classes of
4.1 Decarburization and carburization are two surface con-
hardened and tempered steel products for which specific
ditions created, either intentionally or unintentionally, as with
measurements must be made with respect to their physical
a pre-existing condition created during the rod rolling process,
properties.
the rod/wire annealing process, or while heat treating threaded
1.4 This standard does not purport to address all of the
steel products. Too much of either will adversely affect the
safety concerns, if any, associated with its use. It is the
safety and performance of the threaded product. Therefore,
responsibility of the user of this standard to establish appro-
limits have been established for three different product groups:
priate safety and health practices and determine the applica-
the harder and greater the tensile strength of the product, the
bility of regulatory limitations prior to use.
more susceptible to failure the product becomes if these limits
2. Referenced Documents are exceeded.
2
4.2 When testing to a particular product specification that
2.1 ASTM Standards:
lists the dimensions and microindentation data to be used, that
E3 Guide for Preparation of Metallographic Specimens
data shall take precedence over the tables in this test method.
E384 Test Method for Microindentation Hardness of Mate-
4.3 There are only two viable methods available to detect
rials
these deficiencies, either by the visual method or the microin-
F1789 Terminology for F16 Mechanical Fasteners
dentation method. Both methods are used for routine inspec-
3. Terminology
tionswhenevaluationsareconductedatasinglelocationonthe
product sample.
3.1 Definitions:
4.3.1 Because an evaluation at a specific location may not
be representative of the whole part, the referee method em-
1
This test method is under the jurisdiction of ASTM Committee F16 on
ploys the microindentation method taken as an average of
Fasteners and is the direct responsibility of Subcommittee F16.01 on Test Methods.
evaluationsconductedonfouradjacentthreads.Thisprocedure
Current edition approved May 1, 2005. Published May 2005. Originally
significantly reduces the random test variables when compared
approved in 2004. Last previous edition approved in 2004 as F2328 – 04. DOI:
10.1520/F2328-05.
to testing on a single thread.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.4 Specifying this test method does not specify or imply
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
that testing shall be for either decarburization or carburization
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. alone or for both conditions. When either test method is
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