ASTM B438/B438M-00

Standard Specification for Sintered Bronze Bearings (Oil-Impregnated)

SCOPE
1.1 This specification covers sintered bronze, oil-impregnated bearings made primarily from elemental copper, tin, and graphite powders. The manufacturer may, at his discretion, use prealloyed bronze powder in the blend.
1.2 This specification covers the following variables:
1.2.1 Grades--Available in three bronze base composition grades identifiable by different graphite contents.
1.2.2 Type--Grades 1 and 2 are available in four types described by specific density ranges.
1.3 Bearings ordered to this specification will normally be sized after sintering and will be impregnated with a lubricating oil unless otherwise specified by print.
1.4 The values stated in either inch-pound or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.

General Information

• Status: Historical
• Publication Date: 09-Nov-2000
• ICS: 21.100.01 - Bearings in general
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.04 - Bearings

Relations

• Replaces: ASTM B438/B438M-95ae1 - Standard Specification for Sintered Bronze Bearings (Oil-Impregnated)
• Effective Date: 10-Nov-2000
• Replaced By: ASTM B438/B438M-00a - Standard Specification for Sintered Bronze Bearings (Oil-Impregnated)
• Effective Date: 10-Nov-2000

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: B 438/B 438M – 00
Standard Specification for
1
Sintered Bronze Bearings (Oil-Impregnated)
This standard is issued under the fixed designation B 438/B 438M; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
TABLE 1 Chemical Requirements (Composition, %)
1. Scope
Element Grade 1 Grade 2 Grade 3
1.1 This specification covers sintered bronze, oil-
Copper 87.2–90.5 85.7–90.0 82.8–88.3
impregnated bearings made primarily from elemental copper,
Tin 9.5–10.5 9.5–10.5 9.2–10.2
tin, and graphite powders. The manufacturer may, at his
Graphite 0–0.3 0.5–1.8 2.5–5.0
discretion, use prealloyed bronze powder in the blend.
Iron, max 1.0 1.0 1.0
Total other elements 1.0 1.0 1.0
1.2 This specification covers the following variables:
by difference, max
1.2.1 Grades—Available in three bronze base composition
grades identifiable by different graphite contents.
1.2.2 Type—Grades 1 and 2 are available in four types
4. Materials and Manufacture
described by specific density ranges.
1.3 Bearings ordered to this specification will normally be 4.1 Sintered bronze bearings shall be made by molding or
briquetting metal powder mixtures to the proper density. The
sized after sintering and will be impregnated with a lubricating
oil unless otherwise specified by print. green bearing shall be sintered at a time–temperature relation-
ship to produce a microstructure that is essentially alpha bronze
1.4 The values stated in either inch-pound or SI units are to
be regarded separately as standard. Within the text, the SI units and contains no tin rich phases visible at 3003. Sintered
bronze bearings are normally sized after sintering to maintain
are shown in brackets. The values stated in each system are not
exact equivalents; therefore, each system shall be used inde- the dimensional characteristics required of the bearing. After
sizing and inspection they are impregnated with a lubricating
pendently of the other. Combining values from the two systems
may result in nonconformance with the specification. oil unless otherwise specified.
5. Chemical Composition
2. Referenced Documents
2.1 ASTM Standards: 5.1 The material shall conform to the requirements as to the
chemical composition prescribed in Table 1.
B 328 Test Method for Density, Oil Content, and Intercon-
nected Porosity of Sintered Powder Metal Structural Parts
2 6. Physical Properties
and Oil-Impregnated Bearings
6.1 Density—The density of bearings supplied impregnated
E 9 Test Methods of Compression Testing of Metallic Ma-
3
with lubricant shall be within the limits prescribed in Table 2
terials at Room Temperature
and Table 3, when determined in accordance with Test Method
Volume 03.05 Annual Book of ASTM Standards
B 328.
3. Ordering Information
3.1 Orders for parts under this specification shall include the
TABLE 2 Density Requirements (Oil-Impregnated)
following information:
3
Type Density g/cm
3.1.1 Dimensions and tolerances (Section 9),
A
Grades 1 and 2 1 5.8–6.2
3.1.2 Grade and class (Table 1),
2 6.4–6.8
3 6.8–7.2
3.1.3 Density specification (Table 2 and Table 3), and
4 7.2–7.6
3.1.4 Oil type.
A 3
Maximum density limit of 6.2 g/cm has been established on Type 1 to ensure
meeting an oil content of 27 % minimum. Satisfactory bearings can also be
produced between Type 1 and Type 2. These bearings have slightly higher
strength constants and slightly lower oil content.
1
This specification is under the jurisdiction of ASTM Committee B-9 on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom-
TABLE 3 Density Requirements (Oil-Impregnated)
mittee B09.04 on Bearings.
3
Current edition approved May 2000. Published July 2000. Originally published
Type Density, g/cm
as B 438 – 66 T. Last previous edition B 438 – 95a.
Grade 3 1 5.8–6.2
2
Annual Book of ASTM Standards, Vol 02.05. 2 6.2–6.6
3
Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
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B 438/B 438M
A
TABLE 5 Strength Constant K (Strength Constants, Min) , psi
6.2 Oil Content—Oil content of bearings shall not be less
[MPa]
than shown in Table 4 for each grade and type when deter-
Type Grade 1 Grade 2 Grade 3
mined in accordance with Test Method B 328.
1 15 000 [105] 13 000 [90] 10 000 [70]
2 26 000 [180] 23 000 [160] 15 000 [105]
7. Mechanical Properties
3 37 000 [255] 30 000 [205] . [.]
7.1 The manufacturer and purchaser shall agree on a repre-
4 40 000 [275] 34 000 [235
...