Machinery Lubrication July August 2008

CONTAMINATION CONTROL
forming a barrier preventing the water drops from uniting
and subsequently breaking the emulsion.
There are many materials that could act as emulsifying
agents. Some examples of emulsifying agents include
asphaltines (high molecular weight chemicals containing
metals, sulfur, nitrogen and/or oxygen), phenols (and other
cyclic alcohols), resins, and corrosion and contamination
products such as silt, clays, sulfides and calcium by-products.
Besides the formation of emulsions, other key consequences
of water contamination in the steel mill include the following:
• The restriction of the circulation of the oil
• A reduction in the effectiveness of the filtration system
• Promotion of sludge formation
• Increased oxidation
• Reduction of the oil viscosity and its film-forming properties
(loss of film strength)
• Increased possibility of bacterial growth
• Increased foaming and air entrainment
• Promotion of rusting and corrosion
• Possible cause of some additive precipitation or destabilization
(ZDDP)
• Displacement of polar additives at metal surfaces
The ultimate result of severe or prolonged water contamination
of steel mill lubricants is excessive wear and early
failure of various metal parts, especially the critical bearings
necessary to keep production moving. There is much that the
maintenance department in a steel mill can do to reduce the
extent of water contamination, but because the presence of
water is unavoidable, an effective lubricant must be able to
show resiliency to excessive water. In other words, the oil
must have good demulsibility properties.
Demulsibility
Demulsibility is a property of an oil to separate from water
and resist the formation of emulsions. Ability of an oil to
resist the formation of emulsions in service is the best
measure of demulsibility rather than initial resistance to
water. The oil will perform best if the water content is consistently
kept below 0.5 percent.
Factors that determine the demulsibility of an oil include
the base stocks and additives used in manufacture, along
with the presence of contaminants. Among these factors,
though, the additives used to formulate a particular oil can
have a great affect on how well the lubricant ultimately
performs in a wet environment.
Demulsibility additives (known as demulsifiers) within a
lubricating oil act to break emulsions and promote water
separation in two main ways. First, demulsifiers promote the
Property Method ISO 100 ISO 150 ISO 220 ISO 320 ISO 460 ISO 680
Viscosity at 40°C, cSt ASTM D 445 90-110 135-165 198-242 288-352 414-506 612-748
Viscosity Index ASTM D 2270 90 min. 90 min. 90 min. 90 min. 90 min. 85 min.
Low Temperature Demulsibility ASTM D 2711
Non-EP Method at 125°F
(Modified)
Free water before Centrifugation, mL 30 30 30 30 26 26
Water in Oil, percent Report Report Report Report Report Report
Maximum Emulsion, mL 1.0 1.0 1.0 1.0 1.0 1.0
Dynamic Demulsibility Endurance Test
Clark Labs
Maximum Water in Oil after Centrifuging, percent 10 10 10 10 10 15
Maximum Oil in Water after Centrifuging, percent 1 1 1 1 1 1
Rust Protection ASTM D 665A Pass Pass Pass Pass Pass Pass
Rust Protection ASTM D 665B Optional Optional Optional Optional Optional Optional
Pour Point, °C ASTM D 97 -6 -6 -6 -6 0 0
Flash Point, °C ASTM D 92 195 195 195 195 195 195
Oxidation Resistance, min ASTM 2272 80 80 80 80 80 80
Foaming Characteristics ASTM D 892
Sequence I, mL/mL 50 / 0 50 / 0 50 / 0 50 / 0 50 / 0 50 / 0
Sequence II, mL/mL 50 / 0 50 / 0 50 / 0 50 / 0 50 / 0 50 / 0
Sequence III, mL/mL 50 / 0 50 / 0 50 / 0 50 / 0 50 / 0 50 / 0
Yellow Metals Corrosion ASTM D 130
3 hours at 100°C, Rating 1.0 max. 1.0 max. 1.0 max. 1.0 max. 1.0 max. 1.0 max.
Neutralization Number ASTM D 974 Report Report Report Report Report Report
Table 1. MORGOIL Advanced Lubricant New Oil Specifications (Revision 2.3, March 2004)
28 July - August 2008 machinerylubrication.com Machinery Lubrication