X - Hydraulic Fluids Electronic Handout

© 2006 The Lubrizol Corporation

Hydraulic Fluids

08-12-04 HY100-001


Hydraulic Fluid PrinciplesHydraulic Fluid Functions

• Pressure and power transmission• Controlled flow• Minimize wear• Reduce friction• Provide cooling—act as heat transfer medium• Prevent rust and corrosion• Keep system components free of deposits• Provide a viscous seal

HY102-00206-26-06


Hydraulic PrinciplesAdvantages of Fluid Power

• Force transmitted in any direction• Force multiplication P=F/A• Continuously variable speed control• Easily reversible• Energy efficient

10-01-99 HY101-004


Hydraulic PrinciplesDisadvantages of Fluid Power

• Contamination sensitive• Fluid leakage• Flammable (oil systems)

HY101-005


Hydraulic Fluid PrinciplesHydraulic Fluid Requirements

• Correct viscosity• Wear protection• Oxidative & thermal stability• Hydrolytic stability• Corrosion protection• Resistance to air entrainment and foaming• Demulsifies water

10-17-05 HY102-003


Hydraulic Fluid Market TrendsFluid Trends

• Changing Base Oils• Reserves of Performance• Filterability• Wear Protection When Wet• Air Release• Thermal Stability• Shear Stability• Systems

07-11-02 HY105-022


Hydraulic Fluid Market TrendsFluid Trends

• Longer Fluid Life• Improved Thermal Stability• Improved Filterability• Suitable for Both Industrial and Off-Highway Use• Meet Denison HF-0• Meet Vickers M-2950-S• Meet DIN International Requirements• Meets Cincinnati Milacron• Environmental/Toxicological Concerns• Low Zinc

− Ashless (No Zinc)− Phenol Free− Improved FZG Performance

HY105-012


Hydraulic Fluid Market TrendsOptimizing Additive Chemistry and Base Oils to Meet Application Needs

07-08-03 HY105-024

Better Resistanceto Oxidation

Improved AirRelease Properties

Good AntifoamCharacteristics

Improved ThermalStability

Extended RustPerformance

More Reserves ofAntiwear/EP

Smaller systemsReduced cycle timesHigher temperaturesHigher pressuresLong lifeWater toleranceBase oil flexibility

Improve Fluid Life under Increasingly Stressful Conditions


Hydraulic Fluid Market TrendsIndustrial Fluid Types – Fluid Power Systems

• Hydraulic oils− Antiwear hydraulic− R&O hydraulic− Environmentally friendly (EFL) hydraulic

• Rust and oxidation (R&O) oils− Turbine oils− Circulating oils− Bearing oils

• Compressor oils• Fire resistant fluids

− High water base oil in water or chemical emulsions− Invert (water in oil) emulsions− Water glycol solutions− Synthetic (phosphate ester, polyol ester)

• Others− Paper machine oils

03-01-06 HY105-003


Hydraulic Fluid PrinciplesTypes of Fluids

HY102-02910-19-01

Mineral Oil Based Synthetic Based Water Based Vegetable Oil Based Water

Rust & Oxidation(R&O)

Antiwear (AW)

SyntheticHydrocarbons

Polysiloxanes Phosphate Esters Ethers Esters Halogenated Compounds

Polyglycol Water Glycol Synthetic Solution Emulsion

Soy BeanRapeseed Sunflower

Water-in-Oil (Invert) Oil-in-Water (Soluble Oil)

Regular Micro Emulsion

SiliconesSilicate Esters SilanesPolyethers Arylethers

Flouroesters

Fluorinated Compounds

Mixed HalogenCompounds

Fluorocarbons ChlorinatedHydrocarbons

Zinc-based Ashless


Hydraulic Fluid SpecificationsFluid Types

• Oil Based (92% of market)− HH – refined mineral oil− HL – contains rust and oxidation inhibitors− HM – contains rust, oxidation & antiwear additives (HLP)− HV – HM type with viscosity modifier (multigrade)− HS – synthetic base but with no fire resistance

• Fire Resistant (6% of market)− HFA – 95/5 soluble oil or micro-emulsion− HFB – Invert emulsion (water in oil)− HFC – Water glycol− HFD – Phosphate ester

• Environmentally Acceptable (2% of market)− HE – Biodegradable esters and vegetable base oils

07-06-06 HY107-007


Hydraulic Fluid PrinciplesFactors Influencing Additive Selection

• Performance• Compatibility• No Adverse Reactions• Color• Odor• Ecology• Economics

HY102-03306-26-06


Hydraulic Fluid PrinciplesFactors Influencing Additive Selection

• Better oxidation stability• Higher natural viscosity

index• Much better low

temperature performance

• Lower volatility

HY102-03506-26-06

13608

11760

10800

2700

0

2000

4000

6000

8000

1000

0

1200

0

1400

0

1600

0

Far EasternHydroprocess

N AmericanHydroprocess

EuropeanHydroprocess

Solvent Refined

D943 Oxidation Zinc fluid


Hydraulic Fluid Market TrendsIncreased Pressure/Temperature

• Transient temperatures of 130°C can be seen• Sludge and/or varnish can be a problem• Blockage of fine filters is seen with lower quality fluids• Cincinnati Lamb test is the industry standard for

thermal stability

03-01-06 HY105-020


Hydraulic Products Specification Pyramid

05-18-06 HY107-044

DIN 51524, Part 2Basic Good antiwear

HF-0

Hydraulics Performance

Standard

Top TierHF-0 +

EnhancedPerformance

Thermal stabilityAO protectionHydrolytic stability

Superior rust protectionExcellent antiwearGood filterabilityGood air release


Hydraulic Fluid FundamentalsFormulation

08-02-04 HY111-001


Hydraulic Fluid FormulationTypical Package Constituents

06-26-06 HY111-009

AntioxidantMetal Passivator

Rust Inhibitor

EP

AntifoamDemulisfier

Antiwear


Hydraulic Fluid FormulationAdditive Formulation

06-26-06 HY111-008

Additive R&O AWH Invert Emulsion

Antioxidant X X XAntirust X X XAntiwear agent - X XDetergent - ? XDispersant - ? XViscosity improver - ? -Foam inhibitor ? ? XPour depressant ? ? -Demulsifier ? ? -Metal deactivator ? ? -


Hydraulic Fluid FormulationChemically Inactive Additives

• Viscosity modifiers− Polyacrylates− Polymethacrylates− Polyisobutylenes− Olefin copolymers

• Pour point depressants− Similar to VI modifiers− But lower molecular

weight

10-05-98 HY111-003

• Foam inhibitors− Polysiloxanes− Acrylate type polymers

• Demulsifiers− Polyethylene glycols− Trialkylphosphates− Alkylamines− Carboxy acids


Hydraulic Fluid FormulationChemically Active Additives

• Extreme pressure agents− Sulfurized olefins− Sulfurized fats− Chlorinated paraffins− ZnDTP− Lead soaps

• Friction modifiers− Fatty amines− Fatty acids− Paraffin waxes

• Oxidation inhibitors− Hindered phenols− Aryl amines− Thiophosphate esters

10-05-98 HY111-004

• Rust inhibitors− Barium and calcium

sulfonates− Fatty amines− Phosphoric acid esters− Alkenyl succinic acid

• Metal passivators− Triazoles− Dithiophosphates− Dithiocarbamates


Hydraulic Fluid FormulationBase Fluids

• Mineral oils• Synthetic fluids

− Polyol esters− Diesters− Silicones− Synthetic hydrocarbons

10-05-98 HY111-005


Hydraulic Fluid Market DataPercent of Market Share by Type

05-01-01 HY106-007

0

20

40

60

80

100

Mineral Oil InvertEmulsion

WaterGlycol

PhosphateEster

SyntheticBlends


Hydraulic Fluid FormulationMineral Oils

• Paraffinic− Advantages

• Low cost• Readily available• Easily formulated

− Disadvantages• Lead to hard deposits• Flammable

12-03-98 HY111-006

• Naphthenic− Advantages

• Low cost• Readily available• Easily formulated

− Disadvantages• Does not meet VI

requirements of most specifications

• Flammable• Environmental concern


Hydraulic Fluid FormulationSynthetic Fluids

• Advantages− Low volatility− Cleaner discharge valves− High flash points− Good oxidation resistance− Lower labor costs− Extended service life

10-05-98 HY111-007

• Disadvantages− High cost (5 to 10 times of

mineral oils)− Incompatibility with seals,

paints and packings commonly used with mineral systems

− Contamination with mineral oils

− Disposal costs increased


Hydraulic Fluid FormulationViscosity Modifiers for Hydraulic Applications

• Polymethacrylates (PMA) offer optimum properties − Best efficiency to obtain high VI lift

• Optimised shear stability for hydraulic equipment− Temporary shear− Permanent Shear

• Excellent low temperature properties − can have in-built pour point depressant

• Good demulsibility and filterability properties

07-06-06


Hydraulic Fluid FormulationViscosity Modifiers for Hydraulic Applications

• Caution− There is currently a high level of OEM concern

over the quality of HV fluids available in the market • Filter blocking in Denison Hybrid test• Shear concerns from the field

• Selection of the correct polymer for the application is critical

07-06-06


Hydraulic Fluid FundamentalsIssues

08-02-04 HY111-001


Hydraulic Fluid Market TrendsCleanliness and Filtration

• Fluid cleanliness is critical to system operation• Filters have become finer and more efficient• Filterability tests are regularly required

− AFNOR− Denison

• It is essential for modern oils to pass these tests − Dry and wet

06-14-05 HY105-021


Hydraulic SealsSeal Material

• Nitrile (Buna-N)− Most compatible with petroleum oils− Wide operating temperature range (-40°C to 125°C)− Good to moderate overall performance− Inexpensive− Swells in some synthetic fluids

• Plastics, Fluoro Plastic, Fluoro-Elastomers (Viton, Teflon, Kel-F, Nylon)− Exceptional high temperature performance (to 260°C)− Compatible with most fluids

• Silicone− Very wide operating temperature range (-60°C to 260°C)7− Compatible with most fluids. Choice of five resistant fluids.− Not good for reciprocating seals− Tend to absorb oil at high temperature, causing swelling

• Chloroprene (Neoprene)− Tough material− Used for petroleum fluids

05-19-99 HY104-004


Hydraulic SealsTests Used to Evaluate

• ASTM D 471− Volume change

• ASTM D 2240− Durometer (hardness) change

• ASTM D 412− Tensile strength and elongation

05-19-99 HY104-007


Hydraulic Fluid Market TrendsWear Protection When Wet

• Contamination with water often happens• Water can influence the performance of the fluid

− Corrosion− Hydrolysis− Oxidation

• New pump tests have been introduced with 1% water− Denison T6C− Denison T6H20CB20

07-11-02 HY105-030


Hydraulic Fluid Market TrendsShear Stability

• Longer life fluids in mobile hydraulics require a wider operating temperature range

• Viscosity modifiers and pour point depressants will be required

• Hydraulic fluid shearing− Pressure drop across an orifice− Mechanical action in high shear area− Result: cavitation and pump damage

07-11-02 HY105-031


Hydraulic Fluid Market TrendsAir Release

• Due to smaller hydraulic systems, base oil air release properties have become important

• Systems lose control of precision when air contaminates the oil

• At moderate pressures, e.g. 2000 psi, pumps cavitate• The air release of the base oil impacted by refining

process• Antifoam can negatively impact air release

07-08-03 HY105-032


Hydraulic Fluid Market TrendsCavitation Damage

10-17-05 HY105-033


Hydraulic Fluid Testing ConceptsWater Causes

• Rust (in combination with oxygen)• Fatigue life deterioration of components• Increase in oxidation rate• Emulsions and sludge

06-27-97 HY112-010


Hydraulic Fluid Testing ConceptsResults of Oxidation

• Fluid degradation• Formation of

− Acids− Sludges− Gums− Resins− Varnish

06-27-97 HY112-011


Hydraulic Fluid PrinciplesEffect of Water and Metal Particles on Oil Oxidation

HY102-023

Catalyst Water Hours TanNone No 3500+ 0None Yes 3500+ +0.73Iron No 3500+ +0.48Iron Yes 400 +7.93

Copper No 3000 +0.72

Copper Yes 100 +11.03

06-28-01


DenisonVane Pump

(Anti-Wear)

Denison Piston Pump

(Thermal Stability)


Hydraulic FluidsA Tough World for Hydraulic Oils

• Smaller hydraulic system + odd reservoir shapes− Less time to shed air & water− Cavitation, oxidation, degraded hydraulic operation − Additive hydrolysis, acid & sludge formation

• Higher pressure + smaller reservoir = higher oil temp − Transient temperatures of >130° C − More oxidation – fluid lifetimes under threat− More sludge leads to valve stick & filter blockage

− Increased vane pump severity needs extra antiwear− Caution over higher temp yellow metal protection

• Additive selection and base oil quality becomes more critical

06-27-97



• Increased Cleanliness & Filterability − Maximize equipment availability and oil life− More use of proportional/servo valves − New Denison T7 vane pump − Cleaner fluid delivery + more efficient filtration in service

• Frictional properties are important− Hydraulic power for wet brakes and steering− Japanese JCMAS HK SAE No. 2/Microclutch

• Noise legislation Directive 2003/10/EC

− 80 dB(A) by 2006− Add system insulation or redesign pump?

06-27-97



• Less Oil + More Work = Increased Fluid Stress• Additives are consumed at a greater rate in providing

system protection • Additive quality and careful formulating are more

critical today if performance retention is to be achieved

• Formulating to just meet specification might not work in the future

• Able to lower an End User’s operating cost through formulating

• Opportunities exist to differentiate & build competitive advantage

06-27-97

X - Hydraulic Fluids Electronic Handout

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