Tribologie H

HARDENING OILS
Are used for hardening, tempering and reheating steel. A distinction is made between tempering oils, hot-bath hardening oils, high-performance hardening oils, bright-annealing oils (for shiny surfaces), hardening oils that can be washed off and emulsifiable hardening oils, which can be used depending on the steel type, cooling capacity, hardening process and material requirements.
 

Heat dissipating oil
Mineral or synthetic oil that is temperature- and oxidation resistant with a high flash point, which can be used as a heat exchanging medium for cooling or heating. DIN 51522.
 

HEATING OILS
Are liquid fuels which must be suitable to be burnt in different ways. EL heating fuel is an extra light fuel made of hydrocarbons (middle distillate). They may contain hydrocarbon-soluble active ingredients: DIN 51 603 P 1.
 

HEAVY-DUTY ENGINE OIL (HD OIL)
Engine oil that is specifically adapted to the tough requirements for diesel and spark-ignition engines by adding active substances.
 

High-lubricity oils
Passenger car engines or gear oils which, compared with conventional - e.g. SAE 15W/40 engine oils or SAE 80W/90 gear oils - save fuel when they operate thanks to reduced friction, ensure better starting of engines at low temperatures and supply oil lubrication quickly to the various units. Called Fuel Economy Oils and Fuel Efficient Oils (FEO). The reduction in friction can be achieved by lowering the viscosity, using certain synthetic base oils and/or adding active ingredients that reduce friction. High-lubricity engine oil requirements in accordance with CCMC specifications G 5, Ilsac GF-1 (API SG or SH with EC II).
 

HIGH-PRESSURE LUBRICANT
Lubricating oils and greases with high-pressure additives (Extreme Pressure = EP), which prevent greater wear and seizing where boundary friction is present; the active substances are polar additives, and chlorine, sulphur and phosphorus, etc. in loose compounds; for instance, metal salt layers are created during friction; these prevent direct contact between metals. (See EP lubricants.)
 

HONING OIL
Thin-bodied cutting oil for honing processes when working metal; viscosity approx. 6 to 10 mm2/s at 20°C. Crucial factors are: honing type, speed, material, honing stones, etc.
 

HOT BEARING LUBRICATING GREASES
The more modern designation is high-temperature grease; lithium greases can be used for continuous temperatures up to approx. 130°C and peak temperatures of up to approx. 140°C; bentonite greases can be used for continuous temperatures up to 160°C and special MoS2, silicone and synthetic greases are suitable up to max. 260°C.
 

L, T and M heating oils are liquid fuels made of petroleum, shale oil, and bituminous-coal or lignite tars: DIN 51 603 P 2.
 

S heating oil is a heavy fuel made from processing mineral oil and mineral oil products: DIN 51 603 P 3.
 

ZT and C heating oils are liquid fuels produced by processing shale oil, aromatic fractions, and bituminous-coal and lignite tars: DIN E 51 603 P 4.
 

SA heating oil is a heavy low-sulphur fuel made from processing mineral oil and mineral oil products.
 

HYDRAULIC OILS
Ageing-resistant, thin-bodied, non-foaming, highly refined pressure fluids made of mineral oil and/or synthetic oil with a low pour point for use in hydraulic systems, primarily with hydrostatic drives; they may also be used in hydraulic systems with hydrodynamic drives providing that they comply with the requirements of these drives.
 

HL
These are hydraulic oils (pressure fluids) made of mineral oils with active substances to enhance corrosion protection and resistance to ageing: DIN 51 524 P 1.

HLP
These are hydraulic oils (pressure fluids) made of mineral oils with active ingredients to increase corrosion protection and resistance to ageing, as well as reducing fretting damage in mixed friction areas. DIN 51 524 P 2, VDMA 24 318.
 

HVLP
These are hydraulic oils (pressure fluids) made of mineral oils with active ingredients to increase corrosion protection and resistance to ageing; they also reduce fretting damage in mixed friction areas and improve the viscosity temperature characteristics. DIN 51 524 P 3.
 

HLPD
Are hydraulic oils with detergent additives.
 

HYDRODYNAMIC LUBRICATION
This exists if, when moving, the sliding surfaces are completely separated by a lubricating film.
 

HYDROGENATION
This is the term used for the process to add hydrogen to a chemical compound, causing energy to be released, e.g. adding hydrogen to carbon or hydrocarbon compounds, improving middle distillates, lubricating oils, etc.; destructive hydrogenation is the process that breaks up heavy oils into lighter hydrocarbon compounds by adding hydrogen.
 

HYPOID GEAR OILS
High-pressure lubricating oils with EP additives to improve the lubricating performance and to avoid the likelihood of corrosion; mainly used for final drives in vehicles with spiral-tooth and hypoid bevel-gear drives.