ASTM D7450 Specification for Performance of Rear Axle Gear Lubricants
ASTM D7450 Standard Specification for Performance of Rear Axle Gear Lubricants Intended for API Category GL-5 Service
1. Scope
1.1 This specification covers test methods and acceptance criteria for determining the acceptability of gear oils for applications which specify a lubricant meeting the performance requirements of API Category GL-5 service. Lubricants which meet these performance requirements are typically intended for use in automotive axles, particularly those containing hypoid gears, operating under various combinations of high-speed/shock-load and low-speed/high-torque conditions.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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 Documents
2.1 ASTM Standards:
D130 Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test
D892 Test Method for Foaming Characteristics of Lubricating Oils
D5704 Test Method for Evaluation of the Thermal and Oxidative Stability of Lubricating Oils Used for Manual Transmissions and Final Drive Axles
D6121 Test Method for Evaluation of Load-Carrying Capacity of Lubricants Under Conditions of Low Speed and High Torque Used for Final Hypoid Drive Axles
D7038 Test Method for Evaluation of Moisture Corrosion Resistance of Automotive Gear Lubricants
2.2 Military Standards:
MIL-L-2105C Lubricating Oil, Gear, Multipurpose
MIL-L-2105D Lubricating Oil, Gear, Multipurpose
MIL-PRF-2105E Lubricating Oil, Gear, Multipurpose
2.3 ASTM Test Monitoring Center Documents:
L-42 Test Procedure
2.4 SAE Documents:
J306 Automotive Gear Lubricant Viscosity Classification
J2360 Lubricating Oil, Gear Multipurpose (Metric) Military Use
3. Terminology
3.1 Definitions:
3.1.1 ridging, n - on ring and pinion gears, an alteration of the tooth surface to give a series of parallel raised and polished ridges running diagonally in the direction of sliding motion, either partially or completely across the tooth surfaces of gears.
3.1.2 rippling, n - on ring and pinion gears, an alteration of the tooth surface to give an appearance of a more or less regular pattern resembling ripples on water or fish scales.
3.1.3 pitting, n - on ring and pinion gears, small irregular cavities in the tooth surface, resulting from the breaking out of small areas of surface metal.
3.1.4 spalling, n - on ring and pinion gears, the breaking out of flakes of irregular area of the tooth surface, a condition more extensive than pitting.
3.1.5 scoring, n - on ring and pinion gears, the rapid removal of metal from the tooth surfaces caused by the tearing out of small contacting particles that have welded together as a result of metal-to-metal contact. The scored surface is characterized by a matte or dull finish.
3.1.6 wear, n - on ring and pinion gears, the removal of metal, without evidence of surface fatigue or adhesive wear, resulting in partial or complete elimination of tool or grinding marks or development of a discernible shoulder ridge at the bottom of the contact area near the root or at the toe or heel end of pinion tooth contact area (abrasive wear).
3.2 Definitions of Terms Specific to This Standard:
3.2.1 lubrited, adj - having its surface coated with phosphate.
