ASTM D6121 Test Method for Evaluation of the Load Carrying Capacity of Lubricants
ASTM D6121 Standard Test Method for Evaluation of the Load Carrying Capacity of Lubricants Under Conditions of Low Speed and High Torque Used for Final Hypoid Drive Axles
1. Scope
1.1 This test method is commonly referred to as the L-37 test. This test method covers a test procedure for evaluating the load-carrying, wear, and extreme pressure properties of a gear lubricant in a hypoid axle under conditions of low-speed, high-torque operation.
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI values given in parentheses are provided for informational purposes only.
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. Specific hazard information is given in Sections 4, 7, and 8.
2. Referenced Documents
2.1 ASTM Standards:
D235 Specification for Mineral Spirits (Petroleum Spirits) (Hydrocarbon Dry Cleaning Solvent)
2.2 Military Specification:
MIL-PRF-2105E Lubricating Oil, Gear, Multipurpose
2.3 AGMA National Standard:
Nomenclature of Gear Tooth Failure Modes
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 abrasive wear, n - on ring and pinion gears, removal of material from the operating surface of the gear caused by lapping of mating surfaces by fine particles suspended in lubricant, fuel, air, or imbedded in a surface (CRC Rating Manual No. 18).
3.1.2 adhesive wear, n - on ring and pinion gears, removal of material from the operating surface of the gear caused by shearing of junctions formed between operating surfaces in direct metal-to-metal contact; sheared-off particles either remain affixed to the harder of the mating surfaces or act as wear particles between the surfaces (CRC Rating Manual No. 18).
3.1.3 burnish, n - on ring and pinion gears, an alteration of the original manufactured surface to a dull or brightly polished condition (CRC Rating Manual No. 17).
3.1.4 corrosion, n - in final drive axles, a general alteration of the finished surfaces of bearings or gears by discoloration, accompanied by roughening not attributable to mechanical action (CRC Rating Manual No. 17).
3.1.5 deposits, n - in final drive axles, material of pasty, gummy, or brittle nature adhering to or collecting around any of the working parts (CRC Rating Manual No. 17).
3.1.6 discoloration, n - on ring and pinion gears, any alteration in the normal color of finished steel surfaces (CRC Rating Manual No. 17).
3.1.7 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 (CRC Rating Manual No. 17).
3.1.8 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 (CRC Rating Manual No. 17).
3.1.9 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 (CRC Rating Manual No. 17).
3.1.10 scratching, n - on ring and pinion gears, an alteration of the tooth surface in the form of irregular scratches, of random length, across the tooth surface in the direction of sliding of the surfaces (CRC Rating Manual No. 17).
3.1.11 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 (CRC Rating Manual No. 17).
3.1.12 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 (CRC Rating Manual No. 17).
3.1.13 surface fatigue, n - on ring and pinion gears, the failure of the ring gear and pinion material as a result of repeated surface or subsurface stresses that are beyond the endurance limit of the material. It is characterized by the removal of metal and the formation of cavities (AGMA National Standard).
3.1.14 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) (CRC Rating Manual No. 17).
