ASTM D8227-20

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Designation: D8227 − 18 D8227 − 20
Standard Test Method for
Determining the Coefficient of Friction of Synchronizer
Lubricated by Mechanical Transmission Fluids (MTF) Using
a High-Frequency, Linear-Oscillation (SRV) Test Machine
This standard is issued under the fixed designation D8227; 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 procedure for determining the coefficient of friction of lubricants (fluids) tribologically interacting
with materials used in synchronizers in mechanical transmission (MT) gears under high-frequency linear-oscillation motion using
the SRV test machine. A flat areal contact geometry is applied.
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, 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.
2. Referenced Documents
2.1 ASTM Standards:
D235 Specification for Mineral Spirits (Petroleum Spirits) (Hydrocarbon Dry Cleaning Solvent)
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D5579 Test Method for Evaluating the Thermal Stability of Manual Transmission Lubricants in a Cyclic Durability Test
D5706 Test Method for Determining Extreme Pressure Properties of Lubricating Greases Using a High-Frequency, Linear-
Oscillation (SRV) Test Machine
D7421 Test Method for Determining Extreme Pressure Properties of Lubricating Oils Using High-Frequency, Linear-Oscillation
(SRV) Test Machine
G40 Terminology Relating to Wear and Erosion
2.2 Other Standards:
DIN 51631 Special-boiling-point spirits—Requirements and testing
DIN EN ISO 13565-2 Geometrical Product Specifications (GPS)—Surface texture: Profile method—Surfaces having stratified
functional properties—Part 2: Height characterization using linear material ratio curve
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.L0.07 on Engineering Sciences of High Performance Fluids and Solids (Formally D02.1100).
Current edition approved Oct. 1, 2018Dec. 1, 2020. Published November 2018December 2020. Originally approved in 2018. Last previous edition approved in 2018 as
D8227 – 18. DOI: 10.1520/D8227-18.10.1520/D8227-20.
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 Beuth Verlag GmbH (DIN Deutsches Institut für Normung e.V.), Burggrafenstrasse 6, 10787 Berlin, Germany, http://www.en.din.de
*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
D8227 − 20
DIN EN 17022–3 Heat treatment of ferrous materials; heat treatment methods; case hardening
CEC L-66-99 Evaluation of synchronizer loading parameters and their ability to predict failure
GB/T 3077-2015 Alloy structural steel
YS/T 669-2013 Copper alloy tube of extruded product for synchronizer rings
TL-VW084 (1993) Kupfer-Zink-Legierungen – Werkstoffan forderungen (Copper-Zinc alloys—Material requirements)
3. Terminology
3.1 Definitions:
3.1.1 break-in, n—in tribology, an initial transition process occurring in newly established wearing contacts, often accompanied
by transients in coefficient of friction or wear rate, or both, which are uncharacteristic of the given tribological system’s long-term
behavior. G40
3.1.2 carburization, n—carburizing is not defined in the ASTM Dictionary of Engineering Science and Technology, but is defined
in DIN EN 17022-3 “Heat treatment of ferrous materials; heat treatment methods; case hardening”.
3.1.3 coeffıcient of friction, μ or ƒ, n—in tribology, the dimensionless ratio of the friction force (F) between two bodies to the
normal force (N) pressing these bodies together. G40
3.1.4 lubricant, n—any material interposed between two surfaces that reduces the friction or wear wear, or both, between them.
D4175
3.1.4 carburization, n—carburizing is not defined in the ASTM Dictionary of Engineering Science and Technology, but is defined
in DIN EN 17022-3 “Heat treatment of ferrous materials; heat treatment methods; case hardening”.
3.1.5 Ra (C.L.A.), n—in measuring surface finish, the arithmetic average of the absolute distances of all profile points from the
mean line for a given distance.
3.1.6 Rpk, n—reduced peak height according to DIN EN ISO 13565-2; Rpk is the mean height of the peak sticking out above the
core profile section.
3.1.7 Rvk, n—reduced valley height according to DIN EN ISO 13565-2; Rvk is the mean depth of the valley reaching into the
material below the core profile section.
3.1.8 Rz (DIN), n—in measuring surface finish, the average of all Ry values (peak to valley heights) in the assessment length.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 metal specimen, n—represented by the lower specimen disk in manganese brass alloys, but also friction layers in thermally
sprayed molybdenum coatings, sinter iron, paper and carbon fiber tapes are in use.
3.2.2 seizure, n—localized fusion of metal between the rubbing surfaces of the test pieces. D5706
3.2.2.1 Discussion—
In this test method, seizure is indicated by a sharp rise in the coefficient of friction, over steady state, of greater than 0.3 for over
20 s. In severe cases, a stoppage in the motor will occur (for example, see Test Methods D5706 and D7421).
3.3 Acronyms:
3.3.1 SRV, n—Schwingung, Reibung, Verschleiß (German); oscillating, friction, wear (English translation).
Available from Coordinating European Council (CEC), Services provided by Kellen Europe, Avenue Jules Bordet 142 - 1140, Brussels, Belgium, http://www.cectests.org.
Available from Standardization Administration of China, No. 9 Madian Donglu, Haidian District, Beijing 100088, P.R. China.
Available as a standard of nonferrous industry from Standardization Administration of China, No. 9 Madian Donglu, Haidian District, Beijing 100088, P.R. China.
Available from Volkswagen AG, corporate IP, post stop 1770, D-38346 Wolfsburg, Germany, www.vwgroupsupply.com.
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785, Sheffield Measurement Division, Warner and Swasey, 1985, p. 21.
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785, Sheffield Measurement Division, Warner and Swasey, 1985, pp. 29-31.
D8227 − 20
3.3.2 UNS, n—the Unified Numbering System (UNS) is an accepted alloy designation system in North America.
4. Summary of Test Method
4.1 This test method is performed on SRV test machine using aan areal flat-on-flat geometry oscillating at 50 Hz against a steel
test disk with lubricant (grease) between them. Test load is fixed to 260 N (corresponding to a geometrical contact pressure of
3.1 MPa) using a test temperature of 60 °C and a stroke of 1.0 mm during a test time of 2 h. This test is limited to SRV Models
4 and 5.
NOTE 1—Synchronizer rings operate typically under geometric contact pressures from 2 MPa to 6 MPa.
NOTE 2—Test frequency, stroke length, temperature, and materials and/or coatings used as/on disk and flat material can be varied to simulate field
conditions.
NOTE 3—This test runs in the SRV Models 4 and 5 models horizontally and untilted. SRV Models 4 and 5 can be equipped with a maximum test load
unit of 2500 N.
5. Significance and Use
5.1 This test method can be used to quickly determine the lubricating ability of fully-formulated lubricants used as mechanical
transmission fluids (MTF) to display a frictional behavior against materials used in synchronizers of mechanical gears in
automotive vehicles. This test method has found to be complementary to bench tests (for example, Test Method D5579 and CEC
L-66-99) by using the present test conditions. This test method is a material and application oriented approach based on inputs from
field experiences for characterizing the frictional behavior (coefficient of friction (cof)) using random, discrete, and constant
parameter combinations as seen in field experiences. Users of this test method should determine whether results correlate with field
performance or other applications prior to commercialization.
6. Apparatus
6.1 SRV Test Machine, illustrated in Figs. 1 and 2.
7. Reagents and Materials
7.1 Flat ring disk in carburized 20CrMnTi (similar to ~20MnCr5 and ~SAE 5120) bearing steel in =200.05 mm outer diameter
oil quenched from 800 °C 6 10 °C and tempered at 180 °C 6 10 °C during 8 h followed by air cooling to 60 6 2 HRC. The
contact face has an inner cavity with a diameter of 17 mm 6 0.05 mm with a depth of 1.5 mm 6 0.10 mm (see Fig. 3 and Fig.
X1.1). The contact face has two straight slits at 180° opposite to each other with a width of 1 mm with a depth of 1.5 mm 6
0.10 mm. Functional surfaces shall be free from scratches and any surface damages. The topography of the disk will be determined
by four values:
0.200 μm < Rz (DIN) < 0.350 μm
0.040 μm < Ra (C.L.A.) < 0.060 μm
0.150 μm < R < 0.300 μm
pk
0.200 μm < R < 0.350 μm
vk
7.2 Lower Test Disk—Extruded manganese brass HMn64-8- 5-1.5 according to YS/T 669-2013, homologue to TL-VW084, with
HBW2.5/62.5210-260 hardness or 28025 HV0.2, the surfaces of the disk being lapped and polished. α/ß-phase ratio is 50/50.
Test disks have an outer diameter of 24 mm 6 0.5 mm diameter with a height of 7.8 mm 6 0.1 mm. (spherodization at 450 °C
to 590 °C during 2 h to 6 h in air.) The topography of the disk will be determined by four values:
0.500 μm < Rz (DIN) < 0.700 μm
0.040 μm < Ra (C.L.A.) < 0.060 μm
...