ASTM D4304 Specification for Mineral Lubricating Oil Used in Steam or Gas Turbines
1. Scope
1.1 This specification covers mineral oils used in steam and gas turbine lubrication systems where the performance requirements demand a highly refined mineral base oil compounded with rust and oxidation inhibitors plus selected additives as needed to control foam, wear, demulsibility, and so forth.

1.2 This specification is intended to define the properties of mineral oil-based turbine lubricating oils that are functionally interchangeable with existing oils of this type, are compatible with most existing machinery components, and with appropriate field maintenance, will maintain their functional characteristics.

1.3 This specification is intended to define only new lubricating oil before it is installed in the machinery.

1.4 This specification is intended to be used as a guide. It is possible that oils that do not meet this specification may perform satisfactorily in some turbines.

2. Referenced Documents
2.1 ASTM Standards:
D92 Test Method for Flash and Fire Points by Cleveland Open Cup
D97 Test Method for Pour Point of Petroleum Oils
D130 Test Method for Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (the Calculation of Dynamic Viscosity)
D665 Test Method for Rust-Preventing Characteristics of Inhibited Mineral Oil in the Presence of Water
D892 Test Method for Foaming Characteristics of Lubricating Oils
D943 Test Method for Oxidation Characteristics of Inhibited Mineral Oils
D974 Test Method for Acid and Base Number by Color-Indicator Titration
D1401 Test Method for Water Separability of Petroleum Oils and Synthetic Fluids
D1947 Test Method for Load-Carrying Capacity of Fluid Gear Lubricants
D2272 Test Method for Oxidation Stability of Steam Turbine Oils by Rotating Bomb
D2422 Classification of Industrial Fluid Lubricants by Viscosity System
D3339 Test Method for Acid Number of Petroleum Products by Semi-Micro Color Indicator Titration
D3427 Test Method for Air Release Properties of Petroleum Oils
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4310 Test Method for Determination of the Sludging and Corrosion Tendencies of Inhibited Mineral Oils
D5182 Test Method for Evaluating the Scuffing (Scoring) Load Capacity of Oils (FZG Visual Method)

2.2 ISO Standard:
ISO 4406 Method for Coding the Level of Contamination by Solid Particles

3. Terminology
3.1 Definitions:
3.1.1 Type I mineral oils, n - oils for steam and gas turbine lubricating systems where the machinery does not require lubricants with enhanced load carrying capacity. Such oils normally contain rust and oxidation inhibitors plus other additives as needed to meet the specified performance characteristics. Type I oils usually are available in ISO-VG 32, 46, 68, and 100 (see Classification D2422).

3.1.2 Type II mineral oils, n - oils for steam and gas turbine lubricating systems where the machinery requires enhanced load carrying capacity. These oils are similar to Type I and are typically used in marine turbines. Such oils contain rust and oxidation inhibitors, plus mild extreme pressure (EP) additives and other additives as needed to meet the specified performance characteristics. Type II oils usually are available in ISO-VG 68, 100, and 150.

3.1.3 functional properties, n - those properties of the mineral lubricating oil that are required for satisfactory operation of the machinery. These properties are listed in Section 5.