MRO Quiz

CORRECTLY AND COMPLETELY INTERPRETING OIL ANALYSIS REPORTS

Lubricating oil analysis is an equipment condition monitoring technique that cannot be ignored in today’s competitive marketplace.

The return on investment with an effective oil analysis program can be 100 per cent or more. If the program is well planned and executed it will allow the maintenance department to not only predict potential problems or failures, but to eliminate many of them. The ultimate objective in any maintenance program is to improve equipment reliability. 1. Does your maintenance department have a well-trained lubrication specialist who understands the conditions that cause lubricants to deteriorate?

LOGIC: Conditions that cause rapid oil deterioration include incorrect oil selection, excessive operating temperatures, contamination including water and severe applications that deplete oil addi-

tives causing oxidation or nitration.

2. Does your maintenance department know the benefits of oil analysis?

LOGIC: Benefits include monitoring rates of component wear, viscosity, alkalinity, acidity, additive levels, contaminant types and their sources, determine optimum drain intervals and determine remaining lubricant quality.

3. Does the maintenance department understand that effective oil analysis can provide huge equipment reliability improvements?

LOGIC: Using the correct tests provides effective downtime scheduling, avoidance of unnecessary repairs, shorter repair times, improved planning for operations or maintenance activities, improved monitoring of maintenance tasks, provide guidance for continuous reliability improvement and equipment condition can be trended (even more effectively when used in combination with vibration analysis, ultrasonic monitoring, and thermographic temperature testing).

4. Do the lubrication technicians understand the importance of how and when to obtain effective oil samples for analysis?

LOGIC: To provide effective oil analysis results whose interpretation can be trusted, oil samples must be obtained on a regularly scheduled basis, preferably on an hourly recorded basis when the oil is hot and well-circulated and obtained using the same technique from the same locations to ensure consistency.

SPECTROSCOPIC ANALYSIS ELEMENT SOURCES

5. Does maintenance management understand that oil analysis reports must be properly interpreted if the resulting reports are to be trusted?

LOGIC: Oil viscosity must be reported in CST at 40 and 100 degrees Celsius respectively for multi-grade oils with a tendency to shear. Viscosity changes of 15 per cent or more should be investigated immediately. Water must be monitored carefully depending on the type of equipment. A “trace” of water is about 0.1 to 0.2 per cent or 1,000 to 2,000 PPM. It is a mistake to ignore this much water in certain recirculating systems with high oil flow rates and turbulence that may experience foaming problems with as little as 100 PPM of water.

Aluminum

Antimony Barium

Boron

Calcium

Chlorine Chromium

Cobalt Copper

Indium Iron

Lead

Magnesium Al

Sb Ba

B

Ca

Cl Cr

Co Cu

In Fe

Pb

Mg

Found in blowers, camshaft, turbo and crankshaft bearings, alloy pistons, aluminum casings, super charger/turbocharger blades, engine blocks, a component in dirt containing clay, an alloy in gearboxes and housings, some grease. Used with tin in lead-based babbitt type (journal) bearings. Detergent additive, grease additive, corrosion inhibitor, fuel additive, often found in dust and water. (Rarely an indicator of metallic wear). Antifreeze/coolant additive, (if combined with Na, K, P and sometimes with Si, it CONFIRMS a coolant leak), grease additive, EP additive (limited), anti-wear and mild detergent additive, a constituent found in dirt, and water. An indication of “hard” water, detergent/dispersant additive, oxidation inhibitor, road salt, grease additive, airborne dust/dirt, cement, road salt. (Rarely an indicator of metallic wear) Anti-wear additive, EP additive. (Its use is limited) Piston ring faces, found on some pump component surfaces, cylinder liners, valve seats, gears, shafts, roller/ball bearings, chrome plating, stainless steel components, rust prevention additive. Valve seats, hard metallic coatings. Wrist pin bushings, connecting rod and crankshaft main bearing, cam follower roller bushings, rocker arm clevis pin bushings, connecting rod bushings, camshaft thrust washers, anti-corrosion additive (limited), thread and gasket sealant, copper-antimony, or bronze bearings, rolling element bearing cages, retainers, thrust washers, copper plating, cooling coils, anti-seize compounds, a component in some mechanical seals. (Note: CU+ZN = Brass. CU+SN = Bronze) Some crankshaft bearings. Main component of steel, cylinder liners, malleable iron pistons, hardened steel camshafts, crankshafts, gears, cast iron induction-hardened rocker arms, valve bridges, alloyed steel cam follower rollers, shafts, cast iron cylinder bores, cylinder walls/liners, pistons, valve spools, engine blocks, differential/transmission housings, gearboxes, bearing shells, rust. (Always an indicator of wear). Overlay on bearing surfaces (limited use due to environmental concerns), plain bearings, babbitt bearing metals (combined with antimony and tin), soldering metals, bronze/brass components, sealing gaskets, anti-seize compounds. A constituent in aluminum and steel alloys, detergent additive, an indication of “hard” water, plastic components with talcum fillers, seawater intrusion, airborne dust/clay/sand, gearbox housings, cathodic protection systems.

In systems that contain bronze components too much water can cause severe corrosion problems. In systems that use biodegradable oils, control of water is critical to the life of the oil. The Karl Fischer water test must be part of any effective oil analysis program.

6. Does the maintenance group completely understand the use and proper interpretation of oil degradation conditions such as nitration and oxidation?

LOGIC: Oil degradation conditions can be measured by infrared scan. This test reports soot levels, nitration, oxidation, additive levels, and other conditions that affect the oil’s ability to properly lubricate. Oxidation stability can be tested using the RULER “remaining useful life test” to assess the remaining life of turbine and hydraulic oils. Acid number (AN) is a measure of acidity based on ASTM D664 and should be monitored in critical hydraulic, gear drive, turbine, compressor, and natural gas engine oils.

Accepted recommendation is to replace the oil when the AN “double” that of new oil specifications. Base number (BN) is a measure of the reserve alkalinity remaining in engine oils and is related to the detergent/dispersant ability to counteract acids based on ASTM D2896, providing accurate results of BN that decreases as oil nears the end of service life. The recommendation is oil should be changed when the BN is reduced by ½ that of new oil. (Oxidation rates increase as temperatures increase, while nitration rates increase as temperatures decrease).

7. Does the lubrication specialist know the metallurgical makeup of the equipment components and the purpose of the additives in the oils that are in use?

LOGIC: To avoid confusion and unnecessary reaction it is critical that someone in the maintenance organization is aware of these considerations to ensure proper interpretation of oil analysis reports.

8. How does the maintenance group monitor dirt and dust contamination to determine filter quality?

LOGIC: Effective contamination monitoring requires the use of particle counts as part of ISO 4406 standards.

Manganese

Molybdenum

Nickel

Phosphorus

Potassium

Silicon

Silver Sodium

Sulphur

Titanium Vanadium

Zinc Mn

Mo

Ni

P

K

Si

Ag Na

S

Sn

Ti V

Zn

Detergent additive, unleaded gasoline additive, steel components, sacrificial coatings to aid in ‘wear-in’ of new components. (As an indicator of wear, its levels should decrease) Friction modifier, surface coating on piston rings, anti-wear additive, steel components, alloyed components in aircraft engines and oil coolers. Bearing overlay, turbo charger blades, crude oil constituent, stainless steel components, valve seats, alloy steels, nickel plating, shafts, gears, roller/ball bearings. A common anti-wear/detergent/dispersant additive, EP additive, grease additive, antifreeze/coolant additive (if combined with Na, B, K and sometimes with Si, it confirms a coolant leak), may be found in dust/dirt/clay, washing detergents and fertilizers. (Although it is a constituent of steel, it is not an indicator of metal wear) Antifreeze/coolant additive. If combined with Na, B, P and sometimes with Si, it confirms a coolant leak) Anti-foam additive, dirt/dust/sand, grease additive, antifreeze additive (limited), some elastomeric seals, disc lining, gasket sealant, some synthetic oils, steel components. Some journal bearings, gears, bushings, solder. Road salt, detergent additive (limited), grease additive, seawater intrusion, airborne dust/dirt, antifreeze/coolant additive. (If combined with K, B, P and sometimes Si, it confirms a coolant leak) EP additive, metal working fluid additive (are mildly corrosive and should be avoided where brass and bronze metals are alloyed in the component). Overlay of some connecting rod and crank bearings, surface coating on some components such as pistons, plain bearings, sacrificial overlay of moving components, bronze/brass components, solders, used with copper and antimony in tin-based babbitt (journal) bearings. Anti-wear additive, alloyed components in aircraft engines and turbines. Surface coatings, turbine impeller blades, valves, intrusion of heavy fuel oil, hard steel components, constituent in crude oil, residual/bunker fuel. Anti-wear additive, oxidation inhibitor, corrosion inhibitor as in “ZDDP” additive packages used by most lubricant manufacturers, a constituent in some neoprene seals, bronze/brass components, ca thodic protection systems, solder metals. (Note: the phosphorus in ZDDP is chemically harmful to catalytic converters and titanium and boron is being investigated as potential replacement additives)