ASTM D1474-98

Designation: D 1474 – 98
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Methods for
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Indentation Hardness of Organic Coatings
This standard is issued under the fixed designation D 1474; 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.
This standard has been approved for use by agencies of the Department of Defense.
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1. Scope * E 384, Test Method for Microhardness of Materials
2.2 Other Standards:
1.1 These test methods cover the determination of the
ISO 6441-1 Hardness testing—Part 1: Determination of
indentation hardness of organic materials such as dried paint,
Knoop hardness by measurement of the indentation length
varnish, and lacquer coatings, when applied to an acceptable
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using a microscope
plane rigid surface, for example, metal or glass.
ISO 6441-2 Hardness testing—Part 2: Determination of
1.2 Two methods are covered as follows:
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Knoop hardness by measurement of the indentation depth
Sections
Method A—Knoop Indentation Hardness 6-12
3. Terminology
Method B—Pfund Indentation Hardness 13-19
3.1 Definitions:
1.3 Method A, which has the greater precision, provides
3.1.1 indentation hardness—the resistance to penetration by
hardness values in terms of Knoop Hardness Number (KHN).
an indenter.
Method B provides hardness in terms of Pfund Hardness
3.1.2 Knoop indenter—a pyramidal diamond of prescribed
Number (PHN). Although the hardness value scales of these
dimensions.
methods differ, the methods agree in the ranking of coating
3.1.3 Pfund indenter—hemispherical quartz or sapphire in-
hardness.
denter of prescribed dimensions.
1.4 Test Method A of these test methods is similar in content
3.1.4 Knoop hardness number, KHN—the indentation hard-
(but not technically equivalent) to ISO 6441-1 and ISO 6441-2.
ness determined with a Knoop indenter, and calculated as
1.5 The values stated in inch-pound units are to be regarded
follows:
as the standard. The values given in parentheses are for
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infomation only.
KHN 5 L/A 5 L/l C (1)
p p
1.6 This standard does not purport to address the safety
where:
concerns, if any, associated with its use. It is the responsibility
L 5 load applied to the indenter, kg,
of the user of this standard to establish appropriate safety and
l 5 measured length of long diagonal of the indentation,
health practices and determine the applicability of regulatory
mm,
limitations prior to use.
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C 5 indenter constant relating l to A , and
p p
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A 5 projected area of indentation, mm .
2. Referenced Documents
p
3.1.5 Pfund hardness number, PHN—the indentation hard-
2.1 ASTM Standards:
ness determined with a Pfund indenter, and calculated as
D 823 Practices for Producing Films of Uniform Thickness
2 follows:
of Paint, Varnish, and Related Products on Test Panels
2 2
D 1005 Test Methods for Measurement of Dry-Film Thick-
PHN 5 L/A 5 4L/pd 5 1.27 ~L/d ! (2)
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ness of Organic Coatings Using Micrometers
where:
D 1186 Test Methods for Nondestructive Measurement of
L 5 load/kg applied to the indenter, kg,
Dry Film Thickness of Nonmagnetic Coatings Applied to
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A 5 area of projected indentation, mm , and
2
a Ferrous Base
d 5 diameter of projected indentation, mm.
D 1400 Test Method for Nondestructive Measurement of
Dry-Film Thickness of Nonconductive Coatings Applied
4. Significance and Use
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to a Nonferrous Metal Base
4.1 Indentation hardness measurements have proven to be
useful in rating coatings on rigid substrates for their resistance
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to mechanical abuse, such as that produced by blows, gouging,
These test methods are under the jurisdiction of ASTM Committee D-1 on Paint
and Related Coatings, Materials, and Applications and are the direct responsibility
of Subcommittee D01.23 on Physical Properties of Applied Paint Films.
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Current edition approved Dec. 10, 1998. Published February 1999. Originally Annual Book of ASTM Standards, Vol. 03.01.
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published as D 1474 – 57 T. Last previous edition D 1474 – 92. Available from American National Standards Institute, 11 W 42nd St., 13th
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Annual Book of ASTM Standards, Vol 06.01. Floor, New York, NY 10036.
*A Summary of Changes section appears at the end of this standard.
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D 1474
and scratching. These measurements do not necessarily char- the eyepiece to millimetres.
acterize the resistance to mechanical abuse of coatings that are 8.3 With a 25-g load on the indenter, determine the KHN of
required to remain intact when deformed. a calibrated standard (Note 2) with an assigned value not
greater than 50 KHN. If the obtained value is within 65% of
5. Test Specimens
the assigned value, the instrument is considered to be in
5.1 T
...