ASTM B795-20

Standard Test Method for Determining the Percentage of Alloyed or Unalloyed Iron Contamination Present in Powder Forged (PF) Steel Materials

SIGNIFICANCE AND USE
5.1 Cross-product contamination occurs whenever alloy steel powders are processed in the same equipment as iron powders.  
5.2 Unalloyed iron particles, because they may not harden upon heat treatment, are a potential source of soft spots in low-alloy steel parts.  
5.3 Alloyed iron particles, having higher hardenability than an iron or carbon steel matrix, are a potential source of hard spots.  
5.4 Hard or soft spots may cause problems in service or machining.  
5.5 The results of the tests may be used to qualify parts for shipment in accordance with guidelines agreed between purchaser and manufacturer or to check the suitability of mixes for use in powder forging.
SCOPE
1.1 This test method covers a metallographic procedure for determining the percentage of alloyed or unalloyed iron contamination present in powder forged low-alloy steel materials and the percentage of alloyed iron contamination in powder forged iron and carbon steel materials.  
1.2 Units—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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2020
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.11 - Near Full Density Powder Metallurgy Materials

Standards Content (Sample)

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.
Designation: B795 − 20
Standard Test Method for
Determining the Percentage of Alloyed or Unalloyed Iron
Contamination Present in Powder Forged (PF) Steel
1
Materials
This standard is issued under the fixed designation B795; 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* information is available in the Related Material Section of Vol
02.05 of the Annual Book of ASTM Standards.
1.1 This test method covers a metallographic procedure for
determining the percentage of alloyed or unalloyed iron 3.2 Definitions of Terms Specific to This Standard:
contamination present in powder forged low-alloy steel mate- 3.2.1 cross-product contamination, n—the unintentional
rials and the percentage of alloyed iron contamination in mixing of powders with distinct differences in chemical
powder forged iron and carbon steel materials. composition.
1.2 Units—The values stated in SI units are to be regarded
4. Summary of Test Method
asstandard.Nootherunitsofmeasurementareincludedinthis
standard. 4.1 Asection representing the core region is taken from the
powder forged material and prepared for metallographic ex-
1.3 This standard does not purport to address all of the
amination.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.2 The polished and etched sample is examined micro-
priate safety, health, and environmental practices and deter-
scopically at a magnification of 100× and a systematic point
mine the applicability of regulatory limitations prior to use.
count made of features with etching characteristics different
1.4 This international standard was developed in accor-
from that of the matrix.
dance with internationally recognized principles on standard-
4.3 The amount of contaminant is reported as a percentage
ization established in the Decision on Principles for the
to the nearest 0.1%.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
5. Significance and Use
Barriers to Trade (TBT) Committee.
5.1 Cross-product contamination occurs whenever alloy
2. Referenced Documents
steel powders are processed in the same equipment as iron
2
powders.
2.1 ASTM Standards:
B243Terminology of Powder Metallurgy
5.2 Unalloyed iron particles, because they may not harden
E3Guide for Preparation of Metallographic Specimens
upon heat treatment, are a potential source of soft spots in
E177Practice for Use of the Terms Precision and Bias in
low-alloy steel parts.
ASTM Test Methods
5.3 Alloyed iron particles, having higher hardenability than
an iron or carbon steel matrix, are a potential source of hard
3. Terminology
spots.
3.1 Definitions—Definitions of powder metallurgy terms
5.4 Hard or soft spots may cause problems in service or
can be found in Terminology B243. Additional descriptive
machining.
5.5 The results of the tests may be used to qualify parts for
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal
shipment in accordance with guidelines agreed between pur-
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.11 on Near Full Density Powder Metallurgy Materials.
chaserandmanufacturerortocheckthesuitabilityofmixesfor
Current edition approved April 1, 2020. Published June 2020. Originally
use in powder forging.
approved in 1988. Last previous edition approved in 2013 as B795–13. DOI:
10.1520/B0795-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Apparatus
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
6.1 Equipment for the metallographic preparation of test
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. specimens.
*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 ----------------------
B795 − 20
6.2 A metallographic microscope permitting observation 8.1.2.2 Agoodcontrastisdevelopedbetweenthematrixand
and measurement at a magnification of 100×. the contaminant because of a combination of etching and
staining.The areas containing the highest alloy content are the
7. Sampling
least affected. Unalloyed iron will become darkened in a
low-alloy matrix, and low-alloy particles will remain light in
7.1 Takeam
...

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: B795 − 13 B795 − 20
Standard Test Method for
Determining the Percentage of Alloyed or Unalloyed Iron
Contamination Present in Powder Forged (PF) Steel
1
Materials
This standard is issued under the fixed designation B795; 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 a metallographic procedure for determining the percentage of alloyed or unalloyed iron
contamination present in powder forged low-alloy steel materials and the percentage of alloyed iron contamination in powder
forged iron and carbon steel materials.
1.2 Units—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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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
2.1 ASTM Standards:
B243 Terminology of Powder Metallurgy
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—Definitions of powder metallurgy terms can be found in Terminology B243. Additional descriptive information
is available in the Related Material Section of Vol 02.05 of the Annual Book of ASTM Standards.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 cross-product contamination—contamination, n—the unintentional mixing of powders with distinct differences in
chemical composition.
4. Summary of Test Method
4.1 A section representing the core region is taken from the powder forged material and prepared for metallographic
examination.
4.2 The polished and etched sample is examined microscopically at a magnification of 100× and a systematic point count made
of features with etching characteristics different from that of the matrix.
4.3 The amount of contaminant is reported as a percentage to the nearest 0.1 %.
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 Oct. 1, 2013April 1, 2020. Published November 2013June 2020. Originally approved in 1988. Last previous edition approved in 20072013 as
B795 – 07.B795 – 13. DOI: 10.1520/B0795-13.10.1520/B0795-20.
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 ----------------------
B795 − 20
5. Significance and Use
5.1 Cross-product contamination occurs whenever alloy steel powders are processed in the same equipment as iron powders.
5.2 Unalloyed iron particles, because they may not harden upon heat treatment, are a potential source of soft spots in low-alloy
steel parts.
5.3 Alloyed iron particles, having higher hardenability than an iron or carbon steel matrix, are a potential source of hard spots.
5.4 Hard or soft spots may cause problems in service or machining.
5.5 The results of the tests may be used to qualify parts for shipment in accordance with guidelines agreed between purchaser
and manufacturer or to check the suitability of mixes for use in powder forging.
6. Apparatus
6.1 Equipment for the metallographic preparation of test specimens.
6.2 A metallographic microscope permitting observation and measurement at a magnification
...