Oil fundamentals VI 02 2007

Oil Fundamentals Mong-Ching Lin The Functions of a Lubricant z Reduce friction and wear z Remove heat z Prevent the formation of oxidation product z Act as anti-rust and anti-corrosion agent z Act as a seal z Transport contaminants to the filter for removal z Power transmission Benefit of Oil Analysis z Increase maintenance staffs’ general awareness of lubrication related issue z Predictive maintenance – Up to six month earlier indication of wear related problems – Confirm certain problems detected through vibration – Most informative for engines, compressors, crushers, pulverizers, presses, and gearboxes Benefit of Oil Analysis z Minimize unscheduled downtime: – Indication of component failure – Identify type of damage (chemical, abrasion, fatigue, or other), and – Locations of the damage – Fix the problems before it breaks Oil Analysis Provides: z Means to access the levels and types of contamination and wear in the oil z Lubricant chemical condition - “Is it still fit for use?” z Failure prediction from data trending z Preventive maintenance optimization by effectively define: – Sampling schedule – Oil/filter change schedule Potential Cost Savings from Oil Analysis z Lubricant consolidation z Extended oil change intervals z Extended machine life z Power consumption z Labor Starting an Oil Analysis Program ““Technology Technology Champion ” Champion” z Develops goals and objectives z Designs written procedures for: – storage and dispensing – sampling z Drives the corrective activities z Maintains ultimate responsibility for the program Goals and Objectives z Some of the goals and objectives include: – Reducing unplanned downtime and lubricant related failures – Reducing lubricant procurement costs – Consolidating lubricant supply – Reducing oil disposal costs – Extended machine and lubricant life Storage and Dispensing z Protect the lubricants in storage from contamination z Ensure lubricants being added to machines are free from harmful contaminants z Ensure the correct lubricants are added to machines z Employ good housekeeping practices 10 Identify Machines z Start with a small group of “critical” machines – Critical to production – Critical to safety z Add machines as program progresses – Knowledge and experience developed – Better understanding of sampling intervals and analysis techniques – Experience with establishing Alarms 11 Identify Analysis Techniques z Free oil analysis z Commercial oil laboratory analysis z On-site instrument oil analysis 12 Routes and Schedules z Begin by sampling “critical” machines monthly to develop trends (3-6 months) z Design logical “routes” for simplifying sample collection z Adjust sampling interval based on trend 13 Sampling Points z Install sampling ports for consistency – – – – z circulating portion of a reservoir middle of the fluid level prior to the filter in the return line after the last lubricated component (turbulent flow is desirable) Sample pump/tubing 14 Sampling Procedures z Flush valves/ports prior to collecting z Use new bottles/tubing for each sample z Collect while the machine is running or no longer than 15 minutes after shutdown z Don’t collect samples from drain locations debris and water tend to settle 15 Performance Metrics z Failure avoidance (unscheduled downtime) z Reduced procurement (lube consolidation / extended oil change) z Reduced oil disposal (extended oil change) z Energy savings z Labor (reduced overtime / call ins) 16 Training z Storage and dispensing z Sampling z Contamination control z Analysis techniques z On site analysis 17 Laboratory Analysis Techniques Lubricant Analysis Techniques z z z z z z z z Elemental Analysis FT-IR Viscosity TAN / TBN Water - Karl Fischer, Crackle Test Particle Counting Ferrography - Ferrous Density, Visual WDA RBOT 19 Elemental Spectrometry z z Quantifies the amount of inorganic elements in the oil Methods used include: • Rotrode Spectroscopy, ICP (AES) • Atomic Absorption (AA) z z z Results are reported in parts per million (ppm) Elements are categorized as wear, additives, and contaminants Some particle size limitations - less than microns (depending on the instrument used, the limitation may be much less.) 20 10 Fatigue Wear Repeated deformation in excess of the materials ability to return to its original state causes subsurface cracking 83 Fatigue Wear 84 42 Fatigue Wear 85 Fatigue Wear, 100X 86 43 Fatigue Wear 87 Boundary Lube Wear z Includes: – Micro-delamination – Asperity deformation – Adhesion z Particles formed: – – – – – – Platelets Large particles with striations Black oxides Tempered particles Partially melted/fused particles Spheres 88 44 Micro -delamination Micro-delamination 89 Micro -delamination Micro-delamination 90 45 Asperity deformation 91 Adhesion 92 46 Boundary Lube Wear z Results from: – – – – – Start up - rotational speed = Coast down - rotational speed approaching Wrong lube - viscosity too low No lube High temperature - viscosity decreases with increasing temperature 93 Normal Rubbing Wear, 500X 94 47 Boundary Lube Wear, 100X 95 Boundary Lube Wear, 200X 96 48 Boundary Lube Wear, 500X 97 Corrosion z Corrosion is caused by: – Corrosive contamination (including water) – Additive depletion z Results in: – Very fine (< micron) black powder – Red oxide (rust) resulting from water 98 49 Corrosion, 1000X 99 Corrosion - Rust 100 50 Fretting Wear z Caused by: – Small cyclic motions • between the bearing race and housing • between the bearing race and shaft • between the contacting surfaces of gear teeth z Results in: – Very small platelets (< microns) – Appear as coarse black powdery substance 101 Fretting Wear, 500X 102 51 Contamination z Contaminants such as fibers, dust, dirt, sand, bug legs, paint chips, sealant, pieces of gaskets, anti-seize compounds, and Teflon tape are also commonly found while examining samples Some of these are benign and of no real concern, others are abrasive and cause increased wear All contaminants have the potential to clog filters, servo valves, and oil journals 103 Contamination, Fibers and Sand 104 52 Contamination, Salt from Sea Water 105 Contamination, Bugs 106 53 SEM -EDS, a Powerful Tool for Wear SEM-EDS, Debris Analysis Scanning Electron Microscope (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS): z Higher magnification, better resolution z Elemental analysis on the particles z Pin pointing the origin of particles 107 SEM -EDS Analysis, A Carbon Steel SEM-EDS Sphere 108 54 SEM -EDS Analysis, Glass Fiber SEM-EDS 109 SEM -EDS Analysis, Stainless Steel SEM-EDS Chunk 110 55 Electron -Ray spectrum X Electron Micrograph Micrograph of of Cutting Cutting Wear Wear Ribbon Ribbon XX-Ray spectrum shows shows the the ribbon ribbon is is almost almost pure pure Iron Iron 111 Partially melted aluminum particle 112 56 ... Oil/ filter change schedule Potential Cost Savings from Oil Analysis z Lubricant consolidation z Extended oil change intervals z Extended machine life z Power consumption z Labor Starting an Oil. .. and Viscosity Index z A change in the 40C viscosity of 15% from “new” oil indicates a problem 26 13 Viscosity Viscosity is measured using two capillary viscometers one is maintained at 40C, one... Resources: Options – Free oil analysis – Commercial oil laboratory analysis – On-site instrument oil analysis 38 19 Lubricant Analysis Options Free Oil Analysis: z Viscosity at 40 oC z Elemental