ASTM D7127-05
(Test Method)Standard Test Method for Measurement of Surface Roughness of Abrasive Blast Cleaned Metal Surfaces Using a Portable Stylus Instrument
Standard Test Method for Measurement of Surface Roughness of Abrasive Blast Cleaned Metal Surfaces Using a Portable Stylus Instrument
SIGNIFICANCE AND USE
This method may be useful in assuring conformance of a prepared surface to profile requirements specified by the manufacturer of a protective coating.
This method includes determination of the peak density (number of profile peaks in a specified distance). Some workers in the field believe that optimizing peak height and peak density can improve coating adhesion.
This method allows specifiers to objectively define surface texture after abrasive blast cleaning rather than using subjective terms such as “angular pattern” or “dense and uniform pattern.”
SCOPE
1.1 This test method describes a shop or field procedure for determination of four roughness characteristics of surfaces prepared for painting by abrasive blasting. The procedure uses a portable skidded or non-skidded stylus profile tracing instrument. The three measured characteristics are: Rt, Rmax, and Pc.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 In general, this method should be limited to the measurement of surface roughness where Rmax is in the range 10 to 150 m (0.4 to 6 mil) and where the Peak Count, Pc, is less than 180 peaks/cm (450 peaks/in.).
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.
General Information
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Designation: D7127 − 05
StandardTest Method for
Measurement of Surface Roughness of Abrasive Blast
Cleaned Metal Surfaces Using a Portable Stylus Instrument
This standard is issued under the fixed designation D7127; 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 surface roughness and instrument parameters below are con-
tained in the referenced standards.
1.1 This test method describes a shop or field procedure for
3.1.1 deadband, n—that distance above and below the mean
determination of four roughness characteristics of surfaces
line that a continuous trace line must cross in both directions
prepared for painting by abrasive blasting. The procedure uses
(up and down) to count as a single peak.
a portable skidded or non-skidded stylus profile tracing instru-
3.1.1.1 Discussion—Use of a deadband diminishes the ef-
ment. The three measured characteristics are: Rt, Rmax, and
fect of small, spurious peaks due to noise.
Pc.
3.1.2 evaluation length, n—a sequence of five consecutive
1.2 The values stated in SI units are to be regarded as the
sampling lengths.
standard. The values given in parentheses are for information
3.1.3 Pc, n—the number of peak/valley pairs, per unit of
only.
length, extending outside a “deadband” centered on the mean
1.3 In general, this method should be limited to the mea-
line.
surement of surface roughness where Rmax is in the range 10
3.1.4 Rmax, n—the largest peak to valley measurement is
to 150 µm (0.4 to 6 mil) and where the Peak Count, Pc, is less
determined from the five sampling lengths, and the largest of
than 180 peaks/cm (450 peaks/in.).
these five values is Rmax.
1.4 This standard does not purport to address all of the
3.1.5 Rt, n—the distance between the highest peak and the
safety concerns, if any, associated with its use. It is the
lowest valley within any given evaluation length.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.1.6 sampling length, n—thenominalintervalwithinwhich
bility of regulatory limitations prior to use.
a single value of a surface parameter is determined.
3.1.7 surface preparation, n—the cleaning and profiling of a
2. Referenced Documents
metallic surface using an abrasive blast media or mechanical
2.1 ASME Standard:
means to prepare that surface for coating.
ASME B46.1-2002 Surface Texture, Surface Roughness
3.1.8 surface profile, n—for purposes of the standard, the
Waviness and Lay
positive and negative vertical deviations (peaks and valleys)
2.2 ISO Standards:
are measured from a mean line approximately the center of the
ISO 4287: 1997 Geometrical Product Specifications
profile being evaluated.
(GPS)—Surface Texture: Profile Method—Terms,
3.1.9 surface roughness, n—the combined characteristics of
Definitions, and Surface Parameters
surface profile (height) and peak count (linear density) for a
surface.
3. Terminology
3.1.10 traversing length, n—seven sampling lengths com-
3.1 Definitions—The following definitions are provided as
prising the evaluation length and the pre-travel and post-travel
an aid to users of this document. Formal definitions of the
segments.
4. Summary of Test Method
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
4.1 This test method describes the proper use of a portable
Subcommittee D01.46 on Industrial Protective Painting.
stylus surface roughness measuring device to evaluate specific
Current edition approved Dec. 1, 2005. Published January 2006. DOI: 10.1520/
D7127-05.
surface parameters and evaluate their suitability for the appli-
Available from American Society of Mechanical Engineers (ASME), ASME
cation of the selected coating to the surface being prepared by
International Headquarters, Three Park Ave., New York, NY 10016-5990.
abrasive blasting, or other mechanical means, prior to applica-
Available from International Organization for Standardization (ISO), 1 rue de
Varembé, Case postale 56, CH-1211, Geneva 20, Switzerland. tion.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7127 − 05
4.2 The method describes considerations relevant to setup 8. Preparation of the Sample
of stylus instruments for acquisition of required surface rough-
8.1 Select a 15 by 15 cm (6 by 6 in.) area of the surface to
ness parameters.
be tested that is visibly free from obvious defects such as
scratches, deep marks, or other construction or corrosion
5. Significance and Use
defects.
5.1 This method may be useful in assuring conformance of
8.2 Using a stiff nylon bristle brush, remove any dust or
a prepared surface to profile requirements specified by the
abrasive particles from the surface in the selected sample
manufacturer of a protective coating.
evaluation area. If not removed, such dust and micronic
5.2 This method includes determination of the peak density
metallic particles may cause damage to the stylus and errone-
(number of profile peaks in a specified distance). Some
ous readings.
workers in the field believe that optimizing peak height and
peak density can improve coating adhesion.
9. Calibration and Standardization
5.3 This method allows specifiers to objectively define 9.1 Precisionreproductionsofstandardsurfaceprofilessuch
surface texture after abrasive blast cleaning rather than using
as those used by the manufacturer of the equipment, or
subjective terms such as “angular pattern” or “dense and described in their operational literature, may be used as
uniform pattern.”
calibration standards for the apparatus.
6. Apparatus
10. Procedure
6.1 The apparatus consists of a portable skidded or non-
10.1 Obtain an initial trace m
...
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