Oil analysis 02 2005

Why Do Ferrography / UOA?To Identify Abnormal Wear Conditions Before They Become Significant Enough To Adversely Effect Component Life... Used Lubricant Analysis Trends the physical p

Vibration Institute Piedmont Chapter 14

Barry Schoch PREDICT Ferrography / Used Oil Analysis

February 25, 2005

Phone 800-543-8786 www.predictusa.com

“First Sample in your Trend”

What your Lab can

and

cannot tell you

Why Do Ferrography / UOA?

To Identify Abnormal Wear

Conditions Before They Become

Significant Enough To Adversely

Effect Component Life.

Used Lubricant Analysis

Trends the physical properties of the

lubricant

Determines the chemical breakdown or

contamination of the fluid

Determines the concentration of dissolved elements & additives

 Oxidation, Nitrates, Sulfates,

Water, Fuel, Glycol, Additive Degradation

 Acid & Base Level Trends

 Concentrations to 800ppm

 Concentrations to 10ppm

 NAS & ISO Cleanliness Ratings

 Fuel Dilution

• Large particles in sample

– Likely to settle in sample bottle

– Particles over 80 microns are easily visible to naked eye

• Crackle Test

– Hot Plate set at 115-125C

– Sensitive to between 800 and 1000 ppm depending on oil viscosity and additives

• Measure of shear rate

vs shear stress; i.e resistance to flow

• Measured at constant temperature (40oC or

100oC)

Viscosity

ASTM D-445 Constant Temp.

FT-IR: Used Mineral Oil Spectrum

Water by Karl Fischer Titration

Particle Count Test Results

This shows a typical print

out from a particle counter

displaying results by number

of particles in any one

group.

Total Acid Number

• TAN looking for acidity changes

– In this application, more likely to find

oxidation products

– Acid contaminant likely only through process contamination

– Causes corrosive wear debris and general

increases in the wear rate

Total Base Number

• TBN looking for alkalinity

– Overbase additive applications most likely

(Large Diesel Engines)

– Absence of additive (low TBN) will cause

increases in rates of wear, corrosion, and solid combustion product generation

– Process contamination possible, but not

observed

Ferrography

• Separation of Wear Debris from Lubricant

• Quantitative and Qualitative evaluation of Wear Debris using Trend Analysis

• Assessment of the Severity, Origin &

Development Mechanism of Particles;

• Predict Equipment Wear Condition & Failure Potential

• Results from ordinary wear or equipment damage

• Missing volume goes into the lube system in the form of fine particles

• Wear is generated initially as small particles over time, not large chunks

• Since most of the wear debris is some form of steel, a magnetic field is used for separation

• Debris is so small that a high gradient field

rather than a steady field is required

• Larger particles are affected more strongly than smaller ones, so a rough separation according to size is possible

• Uses optics to determine concentration of wear debris

• Is able to evaluate concentrations of magnetically

attracted wear debris

• Particle size limitation is 300 microns

• Effective trending tool for most types of industrial equipment

• Limitations are for extremely clean lube systems, i.e, hydraulics, some turbines

DR Ferrograph

• View slide made by FM

• Several magnifications

–Speed–Detail

• Identify debris using

–Reflected light–Transmitted light–Polarized light–Color filtered light

Analytical Ferrography

BEARING WEAR

Low Alloy Steel

Steel Prior to Heat Treatment Lead/Tin Babbitt Metal

Copper Alloy

Analytical Ferrography

Rating 1 Rating 2 Rating 3 Rating 4 Rating 5

Rating 6 Rating 7 Rating 8 Rating 9 Rating 10

Analytical Ferrography

Correlation w/ DR Ferrograph

WPC=10 WPC=50 WPC=100 WPC=500 WPC=1000

Equipment Condition Report

Equipment Condition Report

(cont)

• Detect Dissolved up to

8 µ m Particles

• Determine Lubricant Additive Depletion • Detect Fluid Contamination • Determine Lube Physical Condition No • Problems detecting Onset of Abnormal Wear

• Determining Sources of Wear (bearings, gears, seals, rings, etc.)

• Reliable Estimate of Machine Wear Condition

Summary

First Sample Analysis

First Sample Analysis

• Observation i.e., water, large

First Sample Analysis

Limited

Yes

Questions