ASTM B848/B848M-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: B848 − 15 B848/B848M − 21
Standard Specification for
Powder Forged (PF) Ferrous Materials
This standard is issued under the fixed designation B848;B848/B848M; 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 specification covers powder forged ferrous materials fabricated by hot densification of atomized prealloyed or iron
powders and intended for use as structural parts.
1.2 This specification covers powder forged parts made from the following materials:
1.2.1 Compositions:
1.2.1.1 PF-10XX Carbon Steel (produced from atomized iron powder and graphite powder),
1.2.1.2 PF-10CXX Copper-Carbon Steel (produced from atomized iron powder, copper and graphite powders),
1.2.1.3 PF-11XX Carbon Steel with manganese sulfide for enhanced machinability (produced from atomized iron powder,
manganese sulfide, and graphite powders),
1.2.1.4 PF-11CXX, PF-1130CXX, and PF-1135CXX Copper-Carbon Steels with manganese sulfide for enhanced machinability
(produced from atomized iron powder, copper, manganese sulfide, and graphite powders),
1.2.1.5 PF-42XX Nickel-Molybdenum Steel (produced from prealloyed atomized iron-nickel-molybdenum powder and graphite
powder),
1.2.1.6 PF-46XX Nickel-Molybdenum Steel (produced from prealloyed atomized iron-nickel-molybdenum powder and graphite
powder),
1.2.1.7 PF-44XX Molybdenum Steel (produced from prealloyed atomized iron-molybdenum powder and graphite powder), and
1.2.1.8 PF-49XX Molybdenum Steel (produced from prealloyed atomized iron-molybdenum powder and graphite powder).
NOTE 1—Alloy composition designations are modifications of the AISI-SAE nomenclature. For example: 10CXX designates a plain carbon steel
containing copper and XX amount of carbon. Compositional limits of alloy and impurity elements may be different from the AISI-SAE limits. Chemical
composition limits are specified in Section 6.
NOTE 2—XX designates the forged carbon content, in hundredths of a percent, that is specified by the purchaser for the application. For a given specified
carbon content, the permissible limits shall be as specified in 6.2.
This specification 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 Nov. 1, 2015Sept. 1, 2021. Published December 2015 September 2021. Originally approved in 1994. Last previous edition approved in 20102015
as B848 – 10.B848 – 15. DOI: 10.1520/B0848-15.10.1520/B0848_B0848M-21.
*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
B848/B848M − 21
NOTE 3—The old acronym for powder forging P/F has been replaced by PF throughout the document. The change in the prefix for the material
designations is just to match the currently approved acronym for powder forging. No change has been made to the material specification and performance
characteristics for the various powder forged materials.
1.2.2 Grades:
1.2.2.1 Grade A—Density equivalent to a maximum of 0.5 % porosity. The minimum density of those sections of the powder
forged part so designated by the applicable part drawing shall not be less than the value specified in Table 1.
1.2.2.2 Grade B—Density equivalent to a maximum of 1.5 % porosity. The minimum density of those sections of the powder
forged part so designated by the applicable part drawing shall not be less than the value specified in Table 1.
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in
each system mayare not benecessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be
used independently of the other. Combiningother, and values from the two systems may result in non-conformance with the
standard.shall not be combined.
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.
TABLE 1 Minimum Density for Selected Powder Forged Steel
Compositions (Fully Annealed Heat Treatment Condition—Ferrite/
A,B
Pearlite Microstructure)
Density (g/cm )
Chemical Composition
Grade A Grade B
C C
(0.5 % porosity) (1.5 % porosity)
PF-1040 7.81 7.74
PF-1060 7.81 7.73
D D
PF-10C40 7.81 7.74
D D
PF-10C60 7.81 7.73
PF-1140 7.79 7.71
PF-1160 7.78 7.70
D D
PF-11C40 7.79 7.71
D D
PF-11C60 7.79 7.71
D D
PF-1130C50 7.82 7.74
D D
PF-1130C60 7.82 7.74
D D
PF-1135C60 7.82 7.74
PF-4220 7.82 7.74
PF-4240 7.81 7.73
PF-4260 7.80 7.72
PF-4420 7.82 7.74
PF-4440 7.81 7.73
PF-4460 7.81 7.73
PF-4620 7.82 7.74
PF-4640 7.81 7.73
PF-4660 7.81 7.73
PF-4680 7.80 7.72
PF-4920 7.83 7.75
PF-4940 7.82 7.74
PF-4960 7.81 7.74
A
Quench-hardening and tempering will reduce the density values. Normalized
samples may have lower density values then fully annealed materials.
B
For the purpose of determining conformance with this specification, measured
values shall be rounded “to the nearest unit” in the last right-hand digit used in
expressing the specification limit, in accordance with the rounding-off method of
Practice E29.
C
Based on the method described in Smith, D. W., “Calculation of the Pore-Free
Density of PM Steels: Role of Microstructure and Composition,” The International
Journal of Powder Metallurgy, Vol 28, No. 3, 1992, p. 259. Calculations based on
350 ppm max oxygen content and all oxygen combined as 3MnO · Al O · 3SiO .
2 3 2
D
The method described by Smith is not considered applicable to steels with
admixed copper additions. Pore-free densities for these materials were deter-
mined by experiment.
B848/B848M − 21
2. Referenced Documents
2.1 ASTM Standards:
A255 Test Methods for Determining Hardenability of Steel
B243 Terminology of Powder Metallurgy
B311 Test Method for Density of Powder Metallurgy (PM) Materials Containing Less Than Two Percent Porosity
B795 Test Method for Determining the Percentage of Alloyed or Unalloyed Iron Contamination Present in Powder Forged (PF)
Steel Materials
B796 Test Method for Nonmetallic Inclusion Content of Ferrous Powders Intended for Powder Forging (PF) Applications
B797 Test Method for Surface Finger-Oxide Penetration Depth and Presence of Interparticle Oxide Networks in Powder Forged
(PF) Steel Parts
B934 Test Method for Effective Case Depth of Ferrous Powder Metallurgy (PM) Parts Using Microindentation Hardness
Measurements
E3 Guide for Preparation of Metallographic Specimens
E8 Test Methods for Tension Testing of Metallic Materials [Metric] E0008_E0008M
E18 Test Methods for Rockwell Hardness of Metallic Materials
E23 Test Methods for Notched Bar Impact Testing of Metallic Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E350 Test Methods for Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought
Iron
E415 Test Method for Analysis of Carbon and Low-Alloy Steel by Spark Atomic Emission Spectrometry
E562 Test Method for Determining Volume Fraction by Systematic Manual Point Count
E1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by
Various Combustion and Inert Gas Fusion Techniques
E1077 Test Methods for Estimating the Depth of Decarburization of Steel Specimens
2.2 MPIF Standard:
MPIF 35 PF Materials Standards for PF Steel Parts
MPIF Standard 67 Guide to Sample Preparation for the Chemical Analysis of the Metallic Elements in Powder Metallurgy (PM)
Materials
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 under “General Information on PM” on the Annual Book of ASTM
Standards.ASTM B09 web page.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 core region—region, n—a core region is one where there is either no decarburization as determined by the procedure in 9.3.4
or there is no hardened surface as determined by the procedure in S2.2.
3.2.2 critical region—region, n—a critical region of a part is one that requires a density level or a microstructural characteristic
to be separately specified.specified separately.
4. Ordering Information
4.1 Orders for parts conforming to this specification shall include the following:
4.1.1 Alloy composition, including carbon content (see 1.2.1, Section 6, and Table 2),
4.1.2 Grade (minimum density requirement—see 1.2.2 and Section 7),
4.1.3 Heat treatment condition and hardness (see 8.1.3, 8.1.4, and 8.2.3),
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 RoadRd. East, Princeton, NJ 08540–6692.08540, http://www.mpif.org.
B848/B848M − 21
TABLE 2 Chemical Composition Requirements for Powder
A
Forged Parts (Weight %)
Element PF-10XX PF-10CXX PF-11XX PF-11CXX PF-1130CXX PF-1135CXX
Nickel, max 0.10 0.10 0.10 0.10 0.10 0.10
Molybdenum,0.05 0.05 0.05 0.05 0.05 0.05
max
B B B B
Manganese 0.10–0.25 0.10–0.25 0.30–0.60 0.30–0.60 0.30–0.60 0.30–0.60
F F
Copper 0.30 max 1.8–2.2 0.30 max 1.8–2.2 2.7–3.3 3.0–3.8
Chromium, 0.10 0.10 0.10 0.10 0.10 0.10
max
B B
Sulfur, max 0.025 0.025 0.23 0.23 0.23 0.23
Silicon, max 0.03 0.03 0.03 0.03 0.03 0.03
Phosphorus, 0.03 0.03 0.03 0.03 0.03 0.03
max
C C C C C C
Carbon
D D D D D D
Oxygen
E E E E
Total Iron Balance Balance Balance Balance
Element PF-42XX PF-46XX PF-44XX PF-49XX
Nickel 0.40–0.50 1.75–2.00 0.10 max 0.10 max
Molybdenum 0.55–0.65 0.50–0.60 0.80–0.95 1.4–1.6
Manganese 0.20–0.35 0.10–0.25 0.08–0.18 0.08–0.18
Copper, max 0.15 0.15 0.15 0.15
Chromium, 0.10 0.10 0.10 0.10
max
Sulfur, max 0.03 0.03 0.03 0.03
Silicon, max 0.03 0.03 0.03 0.03
Phosphorus, 0.03 0.03 0.03 0.03
max
C C C C
Carbon
D D D D
Oxygen
E E E E
Total Iron Balance Balance Balance Balance
A
For the purpose of determining conformance with this specification, measured
values shall be rounded “to the nearest unit” in the last right-hand digit used in
expressing the specification limit, in accordance with the rounding-off method of
Practice E29.
B
Covers manganese sulfide (MnS) additions of from 0.3 to 0.5 %. The manga-
nese content in solution is similar to PF-10XX or PF-10CXX, that is, 0.10 to
0.25 %.
C
Carbon content shall be as specified by the purchaser.
D
When required, maximum oxygen content shall conform to the amount specified
by purchaser. See S1.
E
For information only. Quantitative determination of this element is not required.
F
Some of the copper may be prealloyed.
4.1.4 Location of critical regions (see 3.2.2),
4.1.5 Whether functional or mechanical property testing is required, what type of testing is required, and what performance level
is required (see 8.1.1, 8.1.2, 8.2.1, and 8.2.2),
4.1.6 Whether the purchaser desires that his representative inspect or witness the inspection and testing of the material prior to
shipment (see 11.1 and 11.2),
4.1.7 Whether there are special microstructural requirements (see Section 9 and S4),
4.1.8 Whether certification of the material is required (see Section 13),
4.1.9 Whether there is a maximum forged-oxygen content (see S1),
4.1.10 Whether case hardening is required (see S2),
4.1.11 Whether there is a maximum area percent porosity requirement for critical regions (see 3.2.2 and S3), and
4.1.12 ASTM designation and year of issue.
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5. Materials and Manufacture
5.1 Make the structural parts by hot forging of powder metallurgy (PM) preforms in confined dies with or without subsequent heat
treatment. Prepare PM preforms by pressing or by pressing and sintering material conforming to the designations in 1.2.1 and
meeting the chemical compositions specified in Section 6 and Table 2.
6. Chemical Composition
6.1 The hot forged material shall conform to the requirements prescribed in Table 2.
6.2 Unless otherwise specified, the hot forged carbon content shall not deviate from that specified by the purchaser by more than
60.05 weight percent.
6.3 A guide for the preparation of samples for the chemical analysis of the metallic elements in PM materials is provided in MPIF
Standard 67.
6.4 Determine the concentration of the elements copper, chromium, manganese, molybdenum, nickel, phosphorus, and silicon in
accordance with Test Method E415 or Test Method E350; X-ray fluorescence (XRF) or inductively coupled plasma, atomic
emission spectrometry (ICP-AES) techniques may also be used for these analyses. Determine the concentration of the elements
carbon and sulfur in accordance with Test Methods E1019.
7. Density Requirement
7.1 The minimum density of those sections of powder forged parts so designated by the applicable part drawing shall not be less
than the values specified in Table 1.
7.2 Determine the density of complete parts or sections of parts in accordance with Test Method B311.
8. Mechanical Property Requirements
8.1 Mechanical Properties:
8.1.1 The preferred method for verifying the acceptable performance of a finished part is for the producer and the purchaser to
agree upon a qualification test to be performed on an actual part. The specific test should be determined following consideration
of the function of the part. An example would be measuring the force needed to break teeth off a gear, using a prescribed test
fixture.
8.1.2 Where the part configuration permits, standard mechanical property test specimens may be machined from the part in the
condition in which it is to be used. (Remove test specimens from parts to be used in the quenched and tempered condition after
heat treatment of the part to ensure the microstructure is representative of the actual part.) The applicable part drawing or purchase
order shall designate the location from which the mechanical property test specimens are to be removed and the type of specimen
to be tested.
8.1.3 The core hardness range of parts shall be in accordance with the applicable part drawing or purchase order.
8.1.4 The surface hardness range of parts shall be in accordance with the applicable part drawing or purchase order.
8.1.5 Typical mechanical properties of Grade A materials covered by this specification are shown in Appendix X1.
8.2 Mechanical Property Test Methods:
8.2.1 Tensile Test Method—When requested, take tensile test specimens from parts in accordance with the applicable part drawing
or purchase order. Test tensile specimens in accordance with Test Methods E8. Determine yield strength by the 0.2 % offset
method.
8.2.2 Impact Energy Test Method—When requested, take Charpy V-notch impact test bars from parts in accordance with the
B848/B848M − 21
applicable part drawing or purchase order. Test impact bars in accordance with Test Methods E23; at room temperature, or, at a
temperature agreed between the producer and purchaser.
8.2.3 Hardness Test Method—Determine hardness measurements in accordance with Test Methods E18. Make core hardness
measurements on sectioned parts within the core region of the part. Determine surface hardness measurements in accordance with
the applicable part drawing on the original forged surface, or, if machined, on the machined part surface.
9. Microstructure Requirements
9.1 Surface Finger Oxide Penetration:
9.1.1 The maximum depth of penetration of surface finger oxides from the finished part surface, for each designated critical region
of a powder forged part, shall not exceed that agreed upon between the producer and purchaser. Designate critical regions by the
applicable part drawing or purchase order.
9.1.2 Determine the surface finger oxide penetration in accordance with Test Method B797.
9.2 Interparticle Oxide Networks:
9.2.1 The extent of any interparticle oxide networks in each designated critical region of a powder forged part shall not exceed
that agreed upon between the producer and purchaser. Designate critical regions on the applicable part drawing or purchase order.
9.2.2 Determine the interparticle oxide networks in accordance with Test Method B797.
9.3 Decarburization Depth:
9.3.1 The maximum depth of complete decarburization (only ferrite present) of surfaces of powder forged parts shall not exceed
that agreed between the producer and purchaser.
9.3.2 The depth of total decarburization (total decarburization = complete decarburization + partial decarburization), the depth at
which core carbon content is reached, shall not exceed that agreed between the producer and purchaser. Alternatively, for quenched
and tempered parts, an effective decarburization depth (depth to a specified hardness) may be specified.
9.3.3 Determine the depth of complete decarburization by the microscopical method in accordance with Test Methods E1077.
9.3.4 Depth of total or effective decarburization.
9.3.4.1 Slow-Cooled or Normalized
...