ASTM B797-15

Standard Test Method for Surface Finger-Oxide Penetration Depth and Presence of Interparticle Oxide Networks in Powder Forged (PF) Steel Parts

SIGNIFICANCE AND USE
5.1 The presence of surface finger-oxide penetration and interparticle oxide networks are two of the properties used to evaluate powder forged steel parts for proper processing. Maximum acceptable depths of penetration of surface finger-oxide penetration and acceptable concentrations of subsurface interparticle oxide networks depend on the component and its service environment.  
5.2 Results of tests may be used to qualify parts for shipment.
SCOPE
1.1 This test method covers a metallographic method for determining the maximum depth of surface finger-oxide penetration and the concentration of subsurface interparticle oxide networks in critical areas of powder forged steel parts.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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

• Status: Historical
• Publication Date: 30-Sep-2015
• ICS: 77.040.99 - Other methods of testing of metals
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.11 - Near Full Density Powder Metallurgy Materials

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:B797 −15
Standard Test Method for
Surface Finger-Oxide Penetration Depth and Presence of
Interparticle Oxide Networks in Powder Forged (PF) Steel
1
Parts
This standard is issued under the fixed designation B797; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* particle boundaries in powder forged parts. Examples of
interparticle oxide networks are shown in Fig. 2.
1.1 This test method covers a metallographic method for
determining the maximum depth of surface finger-oxide pen-
4. Summary of Test Method
etration and the concentration of subsurface interparticle oxide
4.1 A section representing both surface and subsurface
networks in critical areas of powder forged steel parts.
regionsofacriticalareaiscutfromthepowderforgedpartand
1.2 The values stated in SI units are to be regarded as
mounted for metallographic grinding and polishing.
standard. No other units of measurement are included in this
standard. 4.2 For surface finger-oxide penetration, the polished and
unetched sample is examined microscopically at a magnifica-
1.3 This standard does not purport to address all of the
tion of 400 to 500×. The maximum depth of penetration of
safety concerns, if any, associated with its use. It is the
surface finger-oxides is measured.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 4.3 For interparticle oxide network concentration, the pol-
bility of regulatory limitations prior to use. ished and unetched sample is examined microscopically at a
magnification of 200 to 500× to determine the presence of
2. Referenced Document
interparticle oxide networks.
2
2.1 ASTM Standards:
5. Significance and Use
E3Guide for Preparation of Metallographic Specimens
E177Practice for Use of the Terms Precision and Bias in
5.1 The presence of surface finger-oxide penetration and
ASTM Test Methods
interparticle oxide networks are two of the properties used to
E691Practice for Conducting an Interlaboratory Study to
evaluate powder forged steel parts for proper processing.
Determine the Precision of a Test Method
Maximum acceptable depths of penetration of surface finger-
oxide penetration and acceptable concentrations of subsurface
3. Terminology
interparticle oxide networks depend on the component and its
3.1 Definitions of Terms Specific to This Standard:
service environment.
3.1.1 surface finger-oxides—surface finger-oxides are sur-
5.2 Results of tests may be used to qualify parts for
face oxides that follow prior particle boundaries into a powder
shipment.
forged part from the surface and cannot be removed by
physical means such as rotary tumbling. Examples of surface
6. Apparatus
finger-oxides are shown in Fig. 1.
6.1 Equipment for the metallographic preparation of test
3.1.2 interparticle oxide networks—interparticle oxide net-
specimens.
works are continuous or discontinuous oxides that follow prior
6.2 A metallographic microscope permitting observation
and measurement up to a magnification of 500×.
1
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-
mittee B09.11 on Near Full Density Powder Metallurgy Materials.
7. Sampling
Current edition approved Oct. 1, 2015. Published November 2015. Originally
7.1 A metallographic specimen shall be removed from the
approvedin1988.Lastpreviouseditionapprovedin2007asB797–93(2007).DOI:
10.1520/B0797-15.
powder forged part to cover each designated critical area.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Criticalareasshallbedefinedbytheapplicablepartdrawingor
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
the purchaser order. Specimens shall be taken from the powder
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. forged part in the condition in which it is to be supplied. The
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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B797−15
FIG. 1Example of Surface Finger-Oxide Penetration Extending Inward from the Powder Forged Part Surface (Shown more clearly at
highmagnification.)
2

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B797−15
FIG. 2Example of Interparticle Oxide Networks Within a Powder Forged Part (Shown more clearly at high magnification.)
3

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...

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: B797 − 93 (Reapproved 2007) B797 − 15
Standard Test Method for
Surface Finger Oxide Finger-Oxide Penetration Depth and
Presence of Interparticle Oxide Networks in Powder Forged
1
(P/F)(PF) Steel Parts
This standard is issued under the fixed designation B797; 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 Scope*
1.1 This test method covers a metallographic method for determining the maximum depth of surface finger oxide finger-oxide
penetration and the concentration of subsurface interparticle oxide networks in critical areas of powder forged steel parts.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
2. Referenced Document
2
2.1 ASTM Standards:
E3 Guide for Preparation of Metallographic Specimens
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
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 surface finger oxides—finger-oxides—surface finger oxides finger-oxides are surface oxides that follow prior particle
boundaries into a powder forged part from the surface and cannot be removed by physical means such as rotary tumbling.
Examples of surface finger oxides finger-oxides are shown in Fig. 1.
3.1.2 interparticle oxide networks—interparticle oxide networks are continuous or discontinuous oxides that follow prior
particle boundaries in powder forged parts. Examples of interparticle oxide networks are shown in Fig. 2.
4. Summary of Test Method
4.1 A section representing both surface and subsurface regions of a critical area is cut from the powder forged part and mounted
for metallographic grinding and polishing.
4.2 For surface finger oxide finger-oxide penetration, the polished and unetched sample is examined microscopically at a
magnification of 400×. 400 to 500×. The maximum depth of penetration of surface finger oxides finger-oxides is measured.
4.3 For interparticle oxide network concentration, the polished and unetched sample is examined microscopically at a
magnification of 200 to 400×500× to determine the presence of interparticle oxide networks.
5. Significance and Use
5.1 The presence of surface finger oxide finger-oxide penetration and interparticle oxide networks are two of the properties used
to evaluate powder forged steel parts for proper processing. Maximum acceptable depths of penetration of surface finger oxide
finger-oxide penetration and acceptable concentrations of subsurface interparticle oxide networks depend on the component and
its service environment.
1
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 B09.11
on Near Full Density Powder Metallurgy Materials.
Current edition approved March 15, 2007Oct. 1, 2015. Published April 2007November 2015. Originally approved in 1988. Last previous edition approved in 20022007
as B797 – 93 (2002).(2007). DOI: 10.1520/B0797-93R07.10.1520/B0797-15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B797 − 15
FIG. 1 Example of Surface Finger Oxide Finger-Oxide Penetration Extending Inward from the Powder Forged Part Surface (Shown more
clearly at high magnification.)
2

---------------------- Page: 2 ----------------------
B797 − 15
FIG. 2 Example of Interparticle Oxide Networks Within a Powder Forged Part (Shown more clearly at high magnification.)
3

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B797 − 15
5.2 Resu
...