Mobil Arapen™ RB 320

Mobil grease , Japan


Product Description

Mobil Arapen RB 320 is a high performance long-life grease developed for the roller bearings of railroad car journals where no provision is provided for in-service re-lubrication. It is formulated with a mineral base fluid and a mixed lithium / calcium soap thickener. Mobil Arapen RB 320 grease has the high oxidation stability required to maintain good lubrication throughout extended periods of service or storage. It is highly resistant to chemical deterioration that might otherwise produce acids or deposits that are detrimental to long bearing life. Mobil Arapen RB 320 grease has exceptional ability to withstand shear, i.e. retain consistency after prolonged working, as in the churning action of an anti-friction bearing. This grease has been shown to have little effect on seal materials. Largely because of its special calcium-lithium-soap base, Mobil Arapen RB 320 grease has a high resistance to structural change in the presence of water. It is also inhibited to give protection against rusting.


Mobil Arapen RB 320 is fully approved against Specification M-942 of the Association of American Railroads for Journal Roller Bearings Grease for non-field lubricated bearing applications. It is used by major manufacturers of railroad journal bearings as the factory-fill lubricant. Mobil Arapen RB 320 has an application temperature range of -20ºC to +120ºC.


Features and Benefits

Mobil Arapen RB 320 railroad car journal bearing grease offers the following features and benefits:

•  Approved against AAR specification AAR-942

•  Formulated for long service life over a wide range of climatic conditions

•  Exhibits excellent oxidation stability, shear stability, seal compatibility, and water resistance for extended grease life and equipment integrity



     •  Roller bearings of railroad car journals where no provision is proided for in-service re-lubrication.

     •  Factory fill lubricant of major railroad journal bearing manufacturers


Specifications and Approvals

This product has the following approvals:



Properties and Specifications



NLGI 1.5

Thickener Type

Lithium Calcium

Color, Visual

Light Amber

Dropping Point, °C, ASTM D2265


Oxidation Stability, Pressure drop at 100hr, psi, ASTM D942


Oxidation Stability, Pressure drop at 500 hr, psi, ASTM D942


Penetration, 60X, 0.1 mm, ASTM D217


Penetration, Change from 60X to 100,000X, 0.1 mm, ASTM D217


SKF Emcor Rust Test, Distilled Water, ASTM D6138

0 , 0

Viscosity @ 40 C, Base Oil, mm2/s, ASTM D445


Viscosity @ 100 C, Base Oil, mm2/s, ASTM D445


Viscosity Index, ASTM D2270


Health and safety

Health and Safety recommendations for this product can be found on the Material Safety Data Sheet (MSDS) @

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ExxonMobil Japan Godo Kaisha

Shinagawa Grand Central Tower

2-16-4, Konan, Minato-Ku,

Tokyo, 108-8218,


Typical Properties are typical of those obtained with normal production tolerance and do not constitute a specification.  Variations that do not affect product performance are to be expected during normal manufacture and at different blending locations.  The information contained herein is subject to change without notice. All products may not be available locally. For more information, contact your local ExxonMobil contact or visit
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