AAR Manual of Standards and Recommended Practices …

1 IMPLEMENTED 02/201201/2012H [M-942] 1 AAR Manual of Standards and Recommended PracticesJournal Bearings and LubricationM-942 JOURNAL ROLLER BEARING GREASES pecification M-942 Adopted: 1975; Last Revised: SCOPEThis specification covers the lubrication of grease-filled freight car roller bearing/grease seal com-binations that are not lubricated in the field. Lubrication grease used in current interchange ser-vice shall be formulated for a minimum life of 500,000 miles. The Wheels, Axles, Bearings, and Lubrication Committee (hereafter referred to as the Committee) shall approve any grease pro-posed for use in freight car roller bearings (Specification M-934) for interchange APPROVAL individual desiring certification of roller bearing grease shall make written application to the AAR.

2 This application will include the location and schedule of laboratory tests for the cer-tificate of analysis (COA). An AAR observer will witness the vibration test described in paragraph At the discretion of the Committee, an AAR observer may be required to witness other tests. The COA is comprised of the specifications listed in paragraph , with the exception of paragraph , Field service test. The COA shall be submitted to the Committee when the Committee accepts review of the COA, the applicant will be authorized to contact the AAR to make arrangements for the field service test (paragraph ), outlined in Appendix D. The AAR will provide the applicant with information concerning the testing schedule, grease sam-ple size required (200 lb) and fee(s) for testing.

3 The applicant will be allowed reasonable observa-tion of the test and will be furnished a copy of the results after Committee will review the test results and advise the applicant as to the grease s approval. Once approved, no chemical composition or properties of the grease may be changed without Committee approval. Evidence of unauthorized changes will be sufficient cause for approval withdrawal. In addition, the grease manufacturer must meet the requirements of the AAR Manual of Standards and Recommended Practices , Section J, Specification M-1003, Quality Assurance. not approved, the field service test samples will be held for 14 days from the date of the Committee s ruling. The applicant may make a claim to the Committee for a rehearing during this BASIC GREASE REQUIREMENTSThe grease shall be composed of a fluid lubricant and a thickening agent.

4 The fluid component may be a mineral oil or synthetic fluid and the thickener a metallic soap(s) or non-soap substance. The use of viscosity index improvers and bentonites or other clay materials is prohibited. The grease shall be formulated to meet the following friction and protect bearing components against against corrosion caused by moisture accumulated in bearings from suitable oxidation resistance in field compatible with bearing seals and bearing materials in that they do not degrade their free of abrasive/foreign matter and be tolerant of some degree of contamination without adversely affecting 02/2012H [M-942] 201/2012 AAR Manual of Standards and Recommended PracticesJournal Bearings and excessively stiffen in cold weather, causing undue resistance to excessively thin in hot weather and maintain an adequate grease leak from bearing Fluid LubricantPropertySpecificationAnalysis point, F340 oil viscosity @ 100 C14 cSt Grease (page 1 of 2)PropertySpecificationAnalysis 15 points of vendor-submitted value and between 265 to 385 ASTM resistance0 ASTM D-6138 (distilled water) point, F325 service testpassAppendix testAppendix A Consistency 15% max.

5 State of migrationpass Distribution % Grease in min % Grease in min. Seal compatibilitypass Wt. % grease loss 15% D-128 (35-g sample) stabilityASTM D-942 psi drop @ 100 hours10 max. psi drop @ 500 hours25 02/201201/2012H [M-942] 3 AAR Manual of Standards and Recommended PracticesJournal Bearings and LABELING AND PACKAGINGEach grease container shall be clearly marked with the product name, order number, manufac-turer s name, batch number ( Batch No. 12AB3), quantity, and the words AAR-M942. The grease expiration date must be clearly labeled on the container. Grease shall be packed in contain-ers to prevent contamination ( , water, dirt) and shall not be packed with other QUALITY CONTROLOnce approved by the AAR, suppliers shall provide a certificate of analysis to purchasers on a batch-by-batch basis comprised of the following specifications from paragraph : consistency (paragraph ), drop point (paragraph ), percentage moisture (paragraph ), and struc-ture stability (paragraph or ).

6 Lithium and grandfathered M-942 greases Consistency290 to 340 Appendix other greases 100,000 stroke worked consistency 15 points of established structure stability compatibilityAppendix B Hardness 5 points Swell volume 10% Seal bond temperature torquerecord resultsASTM Grease (page 2 of 2)PropertySpecificationAnalysis Method01/2012 IMPLEMENTED 02/2012H [M-942] 401/2012 AAR Manual of Standards and Recommended PracticesJournal Bearings and LubricationAPPENDIX AM-942 APPENDIX AVIBRATION TEST (PARAGRAPH ) SCOPEThis test procedure for journal roller bearing grease/grease seal combinations is based on informa-tion developed that correlates a grease s migration, distribution, mechanical stability, seal compat-ibility, and leakage through seals with service performance in the REQUIRED 1/2-in.

7 12-in. Class F preconditioned, AAR defect-free roller bearing (must be broken in for a minimum of 15,000 miles under load as specified in Specification M-934 before use. The bearing may be reused for subsequent tests as long as it meets the dimensional tolerances specified in the AAR Manual of Standards and Recommended Practices , Section H, Part II). axle to accommodate Class F roller platform scale (.01 lb resolution) ft lb torque wrench (set to release at Recommended torque value) table (500-lb capacity) equipped with V-block bearing mount fixture and capable of a peak-to-peak displacement of 1/16 in. in a vertical plane through the stub axle/test bearing at 38 speed motor capable of 1000 coupling to connect the motor to the stub axle on the vibration seals, type to be determined by applicant (Note: Specification M-942 approves the use of a grease with a particular seal.)

8 Use of a different seal with the grease requires requalification). and temperature recording Bearing the bearing still assembled, use a suitable cone spacer to adjust the lateral to .002 in. to .010 in. Disassemble the bearing, clean it with a suitable solvent, and allow it to dry. Weigh the two dry bearing cones assemblies together and record the weight as D. Weigh the two dry bear-ing seals together and record the weight as F. Weigh the entire bearing assembly and seals minus the end cap, cap screws, and locking plate and record the weight as A. the initial consistency of the grease using ASTM method D-1403 (half scale). Charge the bearing with test grease per the manufacturer s recommendation for the initial fill amount, distributing one third of the grease in each of the following areas: inner cone assembly, outer cone assembly, and cup spacer.

9 Assemble the bearing and seals (pre-lubed with test grease), reweigh the assembly, and record the weight as B. 01/2012 IMPLEMENTED 02/201201/2012H [M-942] 5 AAR Manual of Standards and Recommended PracticesJournal Bearings and LubricationAPPENDIX Bearing that the interference fit of the stub axle journal and bearing is between .0025 in. to .003 in. Coat the axle stub with an acceptable lubricant and apply the bearing. Install the end cap, locking plate, and cap screws and tighten in accordance with the AAR Manual of Standards and Recommended Practices , Section G, Part the bearing in the V-block fixture and lock it so that the cup is securely held. Ensure that the natural frequency of the V-block with the bearing mounted is different than the test fre-quency to avoid resonance.

10 Connect the stub axle by means of a flexible coupling to the drive motor, mounted on a stationary platform. Install the thermocouple into the bearing cup and connect it to the recording equipment to monitor grease temperature throughout the Test ParametersRun the test in accordance with one of the conditions listed INSPECTION/CALCULATIONSAt the conclusion of the test period, remove the bearing from the vibration table. Wipe the exterior clean of any grease that may have emerged. Weigh the bearing assembly minus the end cap, cap screws, and locking plate and record the weight as C. Disassemble the bearing, using care not to disturb the grease in the various bearing components. Weigh the two bearing cone assemblies together and record the weight as E.