ASTM D4417-21

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4417 − 20a D4417 − 21
Standard Test Methods for
Field Measurement of Surface Profile of Blast Cleaned
Steel
This standard is issued under the fixed designation D4417; 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 U.S. Department of Defense.
1. Scope
1.1 These test methods cover the description of techniques for measuring the profile of abrasive blast cleaned surfaces in the field,
shop, and laboratory. There are other techniques suitable for laboratory use not covered by these test methods.
1.2 Method B may also be appropriate to the measurement of profile produced by using power tools.
NOTE 1—The Method B procedure in this standard was developed for use on flat surfaces. Depending on the radius of the surface, the results could have
greater variability with lower values and averages.
1.3 SSPC standard SSPC-PA 17 provides additional guidance for determining conformance with surface profile requirements.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D7127 Test Method for Measurement of Surface Roughness of Abrasive Blast Cleaned Metal Surfaces Using a Portable Stylus
Instrument
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
2.2 SSPC Standard:
SSPC-PA 17 Procedure for Determining Conformance to Steel Profile/Surface Roughness/Peak Count Requirements
These test methods are under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and are the direct responsibility of
Subcommittee D01.46 on Industrial Protective Coatings.
Current edition approved Dec. 1, 2020Jan. 1, 2021. Published December 2020January 2021. Originally approved in 1984. Last previous edition approved in 2020 as
D4417 – 20.D4417 – 20A. DOI: 10.1520/D4417-20A.10.1520/D4417-21.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Society for Protective Coatings (SSPC), 800 Trumbull Dr., Pittsburgh, PA 15205, http://www.sspc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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2.3 ASME Standard:
ASME B46.1-2002 Surface Texture, Surface Roughness Waviness and Lay
2.4 ISO Standards:
ISO 4287: 1997 Geometrical Product Specifications (GPS)—Surface Texture: Profile Method—Terms, Definitions, and Surface
Parameters
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 deadband, n—that distance above and below the mean line that a continuous stylus trace line must cross in both directions
(up and down) to count as a single peak.
3.1.2 evaluation length, n—a sequence of five consecutive stylus sampling lengths.
3.1.3 H, n—the average of the maximum peak-to-valley height distances obtained by measuring the thickness of replica tape.
3.1.3.1 Discussion—
H is the thickness measurement adjusted for tape non-linearity.
L
3.1.4 Pd (peak density), n—the number of peaks per unit area obtained from burnished replica tape.
3.1.5 peak, n—a high point in a surface profile.
3.1.6 Rpc (peak count), n—the number of peak/valley pairs, per unit of length, extending outside a “deadband” centered on the
mean line of a stylus trace.
3.1.6.1 Discussion—
For the purpose of Rpc, a peak is defined relative to an upper and lower height threshold. This is a single number (peak count
threshold) and is the distance from a lower threshold to an upper threshold centered on the mean line of the profile.
3.1.7 Rt, n—the vertical distance between the highest peak and the lowest valley within any given stylus evaluation length.
3.1.8 sampling length, n—the nominal distance parallel to the surface within which surface parameters are determined.
3.1.9 surface profile, n—the height of the major peaks relative to the major valleys.
3.1.10 traversing length, n—seven sampling lengths comprising the evaluation length and the stylus pre-travel and post-travel
segments.
4. Summary of Test Method
4.1 The methods are:
4.1.1 Method A—The abrasive cleaned surface is compared to commercial replicas of various surface profile depths prepared by
different blast media and the range determined. The geometry of the specific abrasive cleaned surface can also be observed.
4.1.2 Method B—The depth of profile relative to the peaks is measured using a fine-pointed probe at a number of locations and
the average of the maximum peak-to-valley distances (or alternatively, the average peak-to-valley distances) is determined.
4.1.3 Method C—A composite plastic tape is impressed into the blast cleaned surface forming a reverse image of the profile. The
average maximum peak-to-valley distance can be measured using a suitable thickness gage. The average of these distances can
be determined from a group of measurements. Specially designed optical readers can also determine the peak density from the tape
replica.
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
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4.1.4 Method D—A trace measurement is taken by a portable stylus surface roughness instrument to obtain maximum
peak-to-valley distance. The average of these distances is determined from a group of five traces. These devices can also determine
peak count information.
5. Significance and Use
5.1 The height of surface profile has been shown to be a factor in the performance of various coatings applied to steel. For this
reason, surface profile should be measured prior to coating application to ensure conformance of a prepared surface to profile
requirements specified by the manufacturer of a protective coating or the coating job specification.
NOTE 2—The peak count/peak density has been shown to be a factor in the performance of various coatings applied to steel. According to research
performed by Roper, Weaver and Brandon , an increase in peak count can improve the adhesion of some coatings to the prepared steel, as well as provide
greater resistance to corrosion undercutting once the coating becomes damaged in service.
NOTE 3—Optical microscope methods serve as a referee method for surface profile measurement methods A and B. Profile depth designations are based
on the concept of mean maximum profile (h max); this value is determined by averaging a given number (usually 20) of the highest peak to lowest valley
measurements made in the field of view of a standard measuring microscope. This is done because of evidence that coating performance in any one small
area is primarily influenced by the highest surface features in that area and not by the average roughness.
6. Apparatus
6.1 Method A—A profile comparator consisting of a number of areas (each approximately one square inch in size), usually side
by side, with a different profile or anchor pattern depth. Each area is marked giving the nominal profile depth in mils or
micrometres. Typical comparator surfaces are prepared with steel shot, steel grit, or sand or other nonmetallic abrasive, since the
appearance of the profile created by these abrasives may differ. The comparator areas are used with or without magnification of
5 to 10 power.
6.2 Method B—A depth micrometer fitted with a pointed probe. The probe is typically machined at a 60° included angle with a
nominal radius of 50 μm and exerting a minimum force of 75 g. The base of the instrument rests on the tops of the peaks of the
surface profile while the spring loaded tip projects into the valleys.
1) The tape consists of a compressible foam coated onto an incompressible polyester substrate.
2) In use, the tape is compressed (“burnished”) against the roughened surface to be measured.
3) After burnishing, the foam retains an impression of the surface.
4) Subsequent measurement of the replica’s thickness, minus that of the substrate, yields surface roughness.
FIG. 1 Illustration of Replica Tape Principle of Measurement
The Effect of Peak Count or Surface Roughness on Coating Performance, JPCL Vol. 22, No. 6, pp 52-64.
John D. Keane, Joseph A. Bruno, Jr., Raymond E. F. Weaver, “Surface Profile for Anti-Corrosion Paints,” Oct. 25, 1976, Steel Structures Painting Council, 4400 Fifth
Ave., Pittsburgh, PA 15213.
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6.3 Method C—A replica tape containing a compressible foam attached to a flexible, incompressible plastic substrate of uniform
thickness. A burnishing tool, having a spherical rounded end approximately 8 mm (0.3 in.) in diameter, is used to impress the foam
face of the tape into the surface to be measured, to create a reverse replica. The thickness of the reverse replica is then measured
using a thickness gage specifically designed for use with this replica tape. This sequence of steps is illustrated in Fig. 1.
6.3.1 Thickness gages suitable for use in this application have plane parallel circular contact surfaces with the top contact surface
that touches the incompressible polyester side having a diameter of 6.3 mm (0.25 in.), a closing force of 100 grams-force 615 g
and an accuracy of at least 65 μm (0.2 mils).
6.3.2 Peak density Pd is extracted from burnished replica tape with an instrument that counts bright spots on a photograph taken
by a digital image sensor (camera).
6.4 Method D—An apparatus consisting of a portable skidded or non-skidded electronic surface roughness measurement
instrument (“tester”) capable of measuring Rt in compliance with ISO 4287 and Rpc in compliance with ASME B46.1. The
apparatus should have a vertical range of at least 300 μm (12 mil) and permit a sampling length of 2.5 mm (0.1 in.) and an
evaluation length of 12.5 mm (0.5 in.) (laboratory experience suggests this vertical range is a practical requirement to meet the
provisions of 6.4.1).
6.4.1 The apparatus should include a stylus with a tip radius of 5 μm (0.2 mil), and permit recording of Rt in the range 10 to 150
μm (0.4 to 6 mil) and Rpc up to 180/cm (450/in.).
6.4.2 Surface deviations are sensed by the stylus and converted to electrical signals within the device. Internal processing converts
these signals into standard surface characterization parameters, which are then displayed or printed.
7. Calibration and Standardization
7.1 Method A:
7.1.1 Comparators require careful handling and if any surface wear is detected the comparator should be discarded.
7.2 Method B:
7.2.1 Before use, each instrument’s accuracy shall be verified by the user in accordance with the instructions of the manufacturer,
employing suitable standards and, if necessary, any deficiencies found shall be corrected.
7.3 Method C:
7.3.1 Before use, each replica tape micrometer’s accuracy shall be verified by the user in accordance with the instructions of the
manufacturer, employing suitable standards and, if necessary, any deficiencies found shall be corrected.
7.4 Method D:
7.4.1 Precision reproductions of standard surface profiles such as those used by the manufacturer of the equipment, or described
in their operational literature, may be used as calibration standards for the apparatus.
8. Preparation of Apparatus
8.1 Method A:
8.1.1 Select the comparator standard appropriate for the abrasive used for blast cleaning.
8.2 Method B:
The sole source of supply of suitable replica tape, Press-O-Film, known to the committee at this time is Testex, 8 Fox Lane, Newark, DE 19711. If you are aware of
alternative suppliers, please proved this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend.
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8.2.1 Prior to use verify that the gage reads zero by placing it on a piece of plate float glass. Hold the gage by its base and press
firmly against the glass. Adjust the instrument to zero if necessary.
8.3 Method C:
8.3.1 Confirm that the target profile is within the primary profile measurement range for replica tape of 20 to 115 μm. Grades
(thicknesses) of tape permit measurement outside this range, but these additional grades should only be used to check
measurements near the ends of the primary range.
8.4 Method D:
8.4.1 Set the apparatus to display the chosen parameters in accordance with the manufacturers’ instructions.
8.4.2 The evaluation length should be set to five sampling lengths. The sampling length and evaluation length should be set to 2.5
mm (0.1 in.) and 12.5 mm (0.5 in.), respectively.
8.4.3 The traversing length of the apparatus should be set to include pre-travel and post-travel segments, usually equal to one
sampling length at the beginning and one sampling length at the evaluation length. These portions of a traverse are discarded by
the instrument in its calculation of surface parameters.
8.4.4 The low frequency (“long wavelength” or “cutoff”) filter should be set to “Gaussian” or “Gaussian 50 %.” In general, the
default setting will be compliant.
8.4.5 If the apparatus has a high frequency (“short wavelength” or “Ls”) filter, it should be set to “off.”
8.4.6 The apparatus should be adjusted (if necessary) to a deadband width (C1 = –C2) in the range 0.5 to 2.0 μm (20 to 80 μin.).
The choice of deadband for profiles as large as those discussed in this standard will have little effect on the measurements. In
general, the default setting will be compliant.
8.4.7 The accuracy of the apparatus should be checked regularly using a calibration block available from the equipment
manufacturer using their written procedure and at their recommended interval.
9. Preparation of the Sample
9.1 Use any metal surface that, after blast cleaning, is free of loose surface interference material, dirt, dust, and abrasive residue.
9.2 Select an area of the surface to be tested that is visibly free from obvious defects such as scratches, deep marks, or other
construction or corrosion defects.
9.3 Using a stiff nylon bristle brush, remove any dust or a
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