ASTM F2328M-05

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Designation: F 2328M – 05
METRIC
Standard Test Method for
Determining Decarburization and Carburization in Hardened
and Tempered Threaded Steel Bolts, Screws and Studs
1
[Metric]
This standard is issued under the fixed designation F 2328M; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope F 1789 Terminology for F16 Mechanical Fasteners
1.1 This test method covers procedures for measuring,
3. Terminology
classifying, and determining the presence of decarburization
3.1 Definitions:
and carburization in the threaded section of hardened and
3.1.1 carburization—process or result of increasing the
tempered metric steel bolts, screws, studs, and similar parts
carbon content of the surface layers of the steel fastener
whichhavebeenheatedtofacilitatefabricationortomodifyits
product.
mechanical properties. This test method is not intended to
3.1.2 decarburization—in accordance with Terminology
address products which are intentionally carburized to achieve
F 1789, is a loss of carbon from the surface layer of the
specific results.
fastener, normally associated with heat treatment.
1.2 Two routine methods are described for measuring the
3.1.3 gross decarburization—also known as complete de-
limits of and determining the presence of decarburization or
carburization, is characterized by a sufficient carbon loss to
carburization; the Optical Method and the Microindentation
show only clearly defined ferrite grains.
Method 1. Either method is appropriate for routine examina-
3.1.4 partial decarburization—characterized as a loss of
tions. The Microindentation Method 2 shall be considered the
carbon sufficient to cause a lighter shade of tempered marten-
referee method.
site than that of the immediately adjacent base metal, but as
1.3 For the purpose of these tests, there are three classes of
being of insufficient carbon loss to show clearly defined ferrite
hardened and tempered steel products for which specific
grains.
measurements must be made with respect to their physical
properties.
4. Significance and Use
1.4 This standard does not purport to address all of the
4.1 Decarburization and carburization are two surface con-
safety concerns, if any, associated with its use. It is the
ditions created, either intentionally or unintenionally, as with a
responsibility of the user of this standard to establish appro-
pre-existing condition created during the rod rolling process,
priate safety and health practices and determine the applica-
the rod/wire annealing process, or while heat treating threaded
bility of regulatory limitations prior to use.
steel products. Too much of either will adversely affect the
2. Referenced Documents safety and performance of the threaded product. Therefore,
2 limits have been established for three different product groups:
2.1 ASTM Standards:
the harder and greater the tensile strength of the product, the
E3 Practice for Preparation of Metallographic Specimens
more susceptible to failure the product becomes if these limits
E 384 Test Method for Microindentation Hardness of Ma-
are exceeded.
terials
4.2 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.
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This test method is under the jurisdiction of ASTM Committee F16 on
4.3 There are only two viable methods available to detect
Fasteners and is the direct responsibility of Subcommittee F16.01 on Test Methods.
these deficiencies: either by the visual method or the microin-
Current edition approved June 15, 2005. Published June 2005. Originally
approved in 2004. Last previous edition approved in 2004 as F 2328M – 04.
dentation method. Both methods are used for routine inspec-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tionswhenevaluationsareconductedatasinglelocationonthe
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
product sample. Because an evaluation at a specific location
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. maynotberepresentativeofthewholepart,therefereemethod
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F 2328M – 05
employs the microindentation method taken as an average of 7.2.2 Allowablelimitsforgrossdecarburization(G)shallbe
evaluationsconductedonfouradjacentthreads.Thisprocedure in accordance with 3.1.3 and the measured values as defined in
significantly re
...