ASTM D6078 Standard Test Method for Evaluating Lubricity of Diesel Fuels
ASTM D6078 Standard Test Method for Evaluating Lubricity of Diesel Fuels by the Scuffing Load Ball-on-Cylinder Lubricity Evaluator (SLBOCLE)
1. Scope
1.1 This test method evaluates the lubricity (load carrying ability) of diesel fuels using a scuffing load ball-on-cylinder lubricity evaluator (SLBOCLE).

1.2 This test method is applicable to middle distillate fuels, such as Grades Low Sulfur No. 1 D, Low Sulfur No. 2 D, No.1 D, and No. 2 D diesel fuels, in accordance with Specification D975; and other similar petroleum-based fuels which can be used in diesel engines.

NOTE 1 - It is not known that this test method will predict the performance of all additive/fuel combinations. Additional work is underway to further establish this correlation and future revisions of the standard may be necessary once this work is complete.

1.3 The values stated in SI units are to be regarded as the standard.

1.4 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 statements are given in Section 7.

2. Referenced Documents
2.1 ASTM Standards:
D329 Specification for Acetone
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity)
D611 Test Method for Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbon Solvents
D770 Specification for Isopropyl Alcohol
D971 Test Method for Interfacial Tension of Oil Against Water by the Ring Method
D975 Specification for Diesel Fuel Oils
D1016 Test Method for Purity of Hydrocarbons from Freezing Points
D1133 Test Method for Kauri-Butanol Value of Hydrocarbon Solvents
D1218 Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids
D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption
D4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D4367 Test Method for Benzene Content in Hydrocarbon Solvents by Gas Chromatography
D5001 Test Method for Measurement of Aviation Turbine Fuels by the Ball-on-Cylinder Lubricity Evaluator (BOCLE)
D6079 Test Method for Evaluating Lubricity of Diesel Fuels by the High-Frequency Reciprocating Rig (HFRR)

2.2 American Iron and Steel Institute Standard:
AISI E-52100 Chromium Alloy Steel

2.3 American National Standards Institute Standard:
ANSI B3.12, Metal Balls

2.4 Society of Automotive Engineers Standard:
SAE 8720 Steel

3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 lubricity,, n - a qualitative term describing the ability of a fluid to affect friction between, and wear to, surfaces in relative motion under load.
3.1.1.1 Discussion - In this test method the lubricity of a fluid is evaluated by the minimum applied load in grams that, at any time during the test, will produce a friction coefficient greater than 0.175 between a stationary ball and a fluid-wetted rotating ring operating under defined conditions.

3.1.2 boundary lubrication, n - a condition in which the friction and wear between two surfaces in relative motion are determined by the properties of the surfaces and the properties of the contacting fluid, other than bulk viscosity.
3.1.2.1 Discussion - Metal-to-metal contact occurs and the chemistry of the system is involved. Physically adsorbed or chemically reacted soft films (usually very thin) support contact loads. As a result some wear is inevitable.

3.1.3 applied load, n - the weight in grams added to the load arm of the SLBOCLE unit.

3.1.4 contact load, n - the force in grams with which the ball contacts the test ring.
3.1.4.1 Discussion - For the SLBOCLE cantilever system the contact load is two times the applied load.

3.1.5 scuffing, n - in lubrication, damage caused by instantaneous localized welding between surfaces in relative motion which does not result in immobilization of the parts.

3.1.6 scuffing load, n - the load required to produce scuffing of surfaces.
3.1.6.1 Discussion - For this test method the scuffing load is defined in terms of the applied load.

3.1.7 friction trace, n - a recorded trace of the tangential friction force in grams.

3.1.8 friction coefficient, n - tangential friction force divided by the contact load.