ASTM B946-11(2016)
(Test Method)Standard Test Method for Surface Finish of Powder Metallurgy (PM) Products
Standard Test Method for Surface Finish of Powder Metallurgy (PM) Products
SIGNIFICANCE AND USE
3.1 The surface finish of a component may be critical for certain applications, affecting properties such as wear resistance, fatigue strength, and coefficient of friction.
3.2 Surface finish may also be critical for component assembly or system performance. Dimensional fit and mating surface interaction may require certain surface finish requirements to meet performance specifications.
SCOPE
1.1 This test method covers measuring the surface finish of powder metallurgy (PM) products at all stages of manufacturing from green compact to fully hardened finished component.
1.2 This test method provides the definition and schematic of some common surface finish parameters (Ra, Rt, and RzISO)
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.4 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 to determine the applicability of regulatory limitations prior to use.
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Designation: B946 − 11 (Reapproved 2016)
Standard Test Method for
Surface Finish of Powder Metallurgy (PM) Products
This standard is issued under the fixed designation B946; 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 4. Interferences
4.1 Because many conventional PM materials contain open
1.1 This test method covers measuring the surface finish of
porosity at the surface, special consideration should be taken
powder metallurgy (PM) products at all stages of manufactur-
when measuring surface finish.
ing from green compact to fully hardened finished component.
4.2 The use of a conical point stylus may result in inaccurate
1.2 This test method provides the definition and schematic
or inconsistent surface finish results because the sharper point
of some common surface finish parameters (R , R , and R )
a t zISO
of the stylus may drop into open porosity on the surface of the
1.3 The values stated in inch-pound units are to be regarded
component.
as standard. The values given in parentheses are mathematical
4.3 A chisel point stylus may be used for better accuracy
conversions to SI units that are provided for information only
and consistency.
and are not considered standard.
4.4 Because the direction of pressing may cause direction-
1.4 This standard does not purport to address all of the
ality in surface finish values, the direction of measurement
safety concerns, if any, associated with its use. It is the
should be specified and reported.
responsibility of the user of this standard to establish appro-
priate safety and health practices and to determine the
5. Apparatus
applicability of regulatory limitations prior to use.
5.1 Surface Finish Measuring Instrument.
2. Referenced Documents
5.2 Stylus—Chisel point, 0.050 in. (1.27 mm) length and
2.1 ASTM Standards: 0.0004 in. 6 30 % (0.010 mm 6 30 %) tip radius as shown in
E691 Practice for Conducting an Interlaboratory Study to Fig. 1. To limit the possibility of the stylus dropping into open
Determine the Precision of a Test Method surface porosity, a chisel point stylus is recommended. If a
cone stylus is used, filtering software shall also be used to
2.2 MPIF Standard:
remove the influence of open surface porosity.
MPIF Standard 58 Method for Determination of Surface
Finish of Powder Metallurgy Products
6. Sampling, Test Specimens, and Test Units
3. Significance and Use 6.1 The test surface shall be clean and free of any oil, dirt,
debris, or foreign material.
3.1 The surface finish of a component may be critical for
6.2 Sufficient surface area shall be available to permit
certain applications, affecting properties such as wear
multiple traverses by the measuring instrument.
resistance, fatigue strength, and coefficient of friction.
6.3 The test surface shall be flat over a sufficient length (in
3.2 Surface finish may also be critical for component
accordance with instrument instructions) to allow proper
assembly or system performance. Dimensional fit and mating
movement of the stylus.
surface interaction may require certain surface finish require-
ments to meet performance specifications.
7. Procedure
7.1 The PM parts manufacturer and purchaser shall agree on
1 the desired location and direction for surface finish measure-
This test method is under the jurisdiction of ASTM Committee B09 on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom- ment.
mittee B09.05 on Structural Parts.
7.2 Place the surface finish instrument in a position suitable
Current edition approved April 1, 2016. Published April 2016. Originally
approved in 2006. Last previous edition approved in 2011 as B946 – 11. DOI: for measuring the test sample.
10.1520/B0946-11R16.
2 7.3 Zero and verify the instrument over the surface finish
Available from Metal Powder Industries Federation (MPIF), 105 College Rd.
East, Princeton, NJ 08540, http://www.mpif.org. range expected for the test sample.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B946 − 11 (2016)
Note 3–The maximum peak-to-valley height of the filtered profile over the
evaluation length l , irrespective of the sampling lengths l .
m e
FIG. 3 R Maximum Peak-to-Valley Height
t
9. Precision and Bias
The Precision for this standard was developed by the Metal
Powder Industries Federation (MPIF) and is used herein with
their permission.
9.1 Precision—The precision of this test has been deter-
Note 1–The stylus is chisel shaped and has a standard radius on the edge and
is 0.050 in. (1.27 mm) wide so that it will not drop into the porosity of the P/M
mined from an
...
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: B946 − 11 B946 − 11 (Reapproved 2016)
Standard Test Method for
Surface Finish of Powder Metallurgy (PM) Products
This standard is issued under the fixed designation B946; 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
1.1 This test method covers measuring the surface finish of powder metallurgy (PM) products at all stages of manufacturing
from green compact to fully hardened finished component.
1.2 This test method provides the definition and schematic of some common surface finish parameters (R , R , and R )
a t zISO
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.4 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 to determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
2.2 MPIF Standard:
MPIF Standard 58 Method for Determination of Surface Finish of Powder Metallurgy Products
3. Significance and Use
3.1 The surface finish of a component may be critical for certain applications, affecting properties such as wear resistance,
fatigue strength, and coefficient of friction.
3.2 Surface finish may also be critical for component assembly or system performance. Dimensional fit and mating surface
interaction may require certain surface finish requirements to meet performance specifications.
4. Interferences
4.1 Because many conventional PM materials contain open porosity at the surface, special consideration should be taken when
measuring surface finish.
4.2 The use of a conical point stylus may result in inaccurate or inconsistent surface finish results because the sharper point of
the stylus may drop into open porosity on the surface of the component.
4.3 A chisel point stylus may be used for better accuracy and consistency.
4.4 Because the direction of pressing may cause directionality in surface finish values, the direction of measurement should be
specified and reported.
5. Apparatus
5.1 Surface Finish Measuring Instrument.
This test method is under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.05
on Structural Parts.
Current edition approved May 1, 2011April 1, 2016. Published May 2011April 2016. Originally published approved in 2006. Last previous edition published 2010
approved in 2011 as B946 – 06 (2010). 11. DOI: 10.1520/B0946-11.10.1520/B0946-11R16.
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 Metal Powder Industries Federation, Federation (MPIF), 105 College Rd. East, Princeton, NJ 08540-6692 U.S.A.08540, http://www.mpif.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B946 − 11 (2016)
5.2 Stylus—Chisel point, 0.050 in. (1.27 mm) length and 0.0004 in. 6 30 % (0.010 mm 6 30 %) tip radius as shown in Fig.
1. To limit the possibility of the stylus dropping into open surface porosity, a chisel point stylus is recommended. If a cone stylus
is used, filtering software shall also be used to remove the influence of open surface porosity.
6. Sampling, Test Specimens, and Test Units
6.1 The test surface shall be clean and free of any oil, dirt, debris, or foreign material.
6.2 Sufficient surface area shall be available to permit multiple traverses by the measuring instrument.
6.3 The test surface shall be flat over a sufficient length (in accordance with instrument instructions) to allow proper movement
of the stylus.
7. Procedure
7.1 The PM parts manufacturer and purchaser shall agree on the desired location and direction for surface finish measurement.
7.2 Place the surface finish instrument in a position suitable for measuring the test sample.
7.3 Zero and verify the instrument over the surface finish range expected for the test sample.
7.4 Place the test sample under the stylus and then lower the stylus to the measuring position in accordance with the instrument
instructions.
7.5 Measure the surface finish of the test surface. A minimum of three traverses at different locations is recommended.
8. Report
8.1 Report the surface finish
...
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