WHERE DOES ALL THAT METAL COME FROM?
John S. Evans
Issue 47
Technical Bulletin
Oil analysis involves the extraction of a small, representative sample of oil from a lubricated
piece of machinery and subjecting it to a whole battery of chemical and physical tests in a
laboratory. The data is then interpreted to produce a report. There are three fundamental areas
of interest in an oil analysis report, they are: the health of the machine being sampled, the
health of the oil lubricating that machine and the levels of contamination.
Of the many tests that an oil sample can be subjected to, perhaps the most well known is a
spectrometric analysis. This is often referred to in the industry by the acronym, SOAP, which
stands for Spectrometric Oil Analysis Programme. There are a variety of instruments that can
carry out this test but the one that is most commonly used in large laboratories is called an
inductively coupled plasma or ICP; Wearcheck operates four such instruments.
The purpose of the test is to measure the concentration of wear metals (machine health), oil
additives (oil health) and contaminants. These parameters are determined by the
concentrations of various elements from the periodic table. Wearcheck measures 29 of these
elements and they fall into the various categories such as copper which is a wear meal, calcium
which forms part of an oil additive or silicon which is a constituent of dirt (contaminant). Note
that quite a few elements can belong to more than one category.
1/3
WHERE DOES ALL THAT METAL COME FROM?
The
spectrometer.
temperatures
When
different
so
frequencies.
element
would
oil
sample
in
frequencies.
not
different
the
The
be
can
The
oil.
is
visible
intensity
mixed
be
plasma
elements
achieved,
Most
to
with
the
of
is
of
a
are
each
generated
human
this
suitable
as
subjected
light
frequency
high
eye
is
solvent
as
by
in
but
10
a
to
the
powerful
is
the
such
000ºC
ultra-violet
proportional
ICP
high
introduced
which
has
radio
temperatures
detectors
part
is
frequency
to
as
the
into
of
hot
the
concentration
the
that
as
electromagnetic
they
discharge
plasma
the
can
will
surface
see
of
emit
of
these
and
the
each
of
light
very
the
spectrum
of
sun.
high
In
various
technical
common
order
elements
to
element
bulletin
interpret
will
come
sources
an
look
oil
from
at
analysis
are.
which
and
which
report
elements
of
accurately
the
belong
three
categories
to
itthe
is
which
vitally
categories
important
they
can
belong
to
know
what
to.
where
the
This
most
the
element.
By
far
the
biggest
category
is
the
wear
metals,
of
which
iron
is
the
most
common
wearing
Iron
they
liners
valves.
shafts
–come
and
chemical
and
In
the
from
anti-friction
crankshaft
symbol
the
Latin
and
(rolling
Fe
are
drivetrain
(if
the
some
element)
of
major
the
of
components
element,
the
wearing
bearings.
chemical
in
components
iron
this
symbols
is
case
the
major
ferrum).
do
along
not
constituent
with
In
engines
timing
sense
of
gears,
the
the
itas
is
cylinder
gears,
because
shafts
and
which
contaminant.
occurs
evaporate
contaminants
may
iron
whereby
at
reacts
indicate
working
Rust,
behind
the
with
containing
contamination
coolant
in
temperature
water
the
oil.
comes
(which
iron,
This
or
and
into
can
contains
will
component
pressure
contact
be
formed
covered
oxygen)
with
whilst
degradation.
in
in
cooling
and
more
leaving
lubricating
atmospheric
detail
systems.
Finally,
coolant
under
oil
then
iron
If
additives
oxygen,
an
sodium.
can
the
internal
also
coolant
rust
and
be
coolant
can
a
may
form
leak
piston.
transmissions,
housings
also
Almost
be
in
general
made
without
torque
of
are
the
convertors
exception,
often
metal
made
Al.
and
are
all
The
found
of
pistons
made
most
aluminium.
in
of
common
a
are
variety
aluminium.
made
Thrust
source
of
from
components.
washers,
Hydraulic
aluminium
of
aluminium
plain
pump
or
bearings
their
in
housings
engines
alloys.
and
and
is
In
bushes
the
Aluminium
is
grit
Traditionally
and
usually
transferring
is
aluminium
highly
in
agearboxes
can
ratio
abrasive
dirt
into
oxides
also
is
of
an
detected
Al:Si
be
and
so
a
wetted
of
contaminant.
ifname
dirt
between
by
be
entry
the
component
very
presence
1:2
occurs
dangerous
It
up
is
an
to
then
then
of
1:5.
additive
silicon,
aluminium
aluminium
to
any
component
however,
lubricated
may
usually
be
most
of
piece
accompanies
present.
some
dirt
of
is
greases
machinery.
a
Common
mixture
the
so
silicon
of
dirt,
iffrom
grease
silicon
dust,
– in
Chromium
coated
made
chromium
of
can
an
aluminium).
component.
indication
be
of
with
a
cast
contaminant
as
–
the
chemical
of
an
iron.
Chromium
metal.
dirt
alloying
Shafts,
entry;
too,
symbol
On
metal
note
can
rare
gears
in
areas
Cr. also
occasions,
that
with
and
In
be
where
dirt
iron
anti-friction
engines,
used
does
to
the
form
as
not
metal
liners
the
aand
certain
always
bearings
surface
rings
can
is
being
steels
are
have
be
hardening
can
normally
chromed
mined
to
and
contain
consist
this
itmake
coating
made
and
can
trace
can
of
the
show
silicon
occur
of
on
amounts
rings
chromium
gears.
up
in
(and
in
are
most
the
of
Chromium
then
or
oil
types
are
as
Finally,
types
system
the
oil.
of
This
leaks
chromium
coolant
is
into
usually
conditioners
the
can
oil
seen
sometimes
then
in
contain
electromotive
can
be
sodium
seen
evaporate
as
diesel
chromate
an
off
indication
applications.
leaving
and
of
once
the
an
chromium
internal
again,
ifand
coolant
water
and
sodium
from
leak.
the
Certain
behind
cooling
Iron,
up
elevated
abnormally.
the
aluminium
metallurgy
silicon
and
as
of
dirt
chromium
the
entry
liners,
through
pistons
can
often
the
and
air
be
rings.
intake
seen
This
together
system
is
usually
can
in
engine
cause
seen
oil
these
in
samples
conjunction
components
they
with
to
make
wear
have
silicon
surprised
many
can
to
be
different
see
an
silicon
additive.
sources.
in
new
Si.
Usually
Silicon
Although
engine
found
is
oil
part
silicon
in
samples;
a
of
concentration
is
a
chemical
usually
do
not
seen
added
panic,
of
as
5high
to
this
to
an
10
oils
indication
is
ppm,
not
to
stop
due
so
of
do
them
to
dirt
not
foaming
entry
be
can
so
Silicon
there
bentonite
leach
an
is
into
indication
is
an
found
greases)
the
internal
oil.
in
of
The
chemicals
coolant
and
a
problem.
assembly
assembly
leak
used
along
compounds
compounds
in
coolant
with
sodium.
can
conditioners
often
generate
Greases
so
very
silicone
contain
itof
can
high
show
based
levels
silicon
up,
of
chemicals
(particularly
as
silicon
a
contaminant,
but
that
this
easily
is
not
sometimes
can
well
strictly
have
as
many
a
being
used
metal,
sources
an
in
so
the
additive
calling
construction
and
and
can
this
a
fit
a
contaminant,
wear
into
of
pistons
all
metal
three
to
would
silicon
categories.
reduce
be
can
their
chemically
also
coefficient
be
a
incorrect).
wearing
of
expansion.
compound
Silicon
carbide
Silicon
(it
is
(and
sometimes
–
components.
chemical
gears)
Coatings,
along
Ni.
Nickel
with
similar
iron.
is
most
to
Valves
chromium
commonly
and
valve
can
seen
contain
guides
as
an
nickel.
alloy
contain
of
anti-friction
nickel
and
bearings
some
Nickel
as
seen
aan
combustion
in
marine
also
agrouping
engine
component
by-product
applications.
of
making
most
heavy
itconstituent
a
contaminant
and
medium
as
furnace
well
oils
a
wear
so
this
metal.
shows
This
is
normally
in
the
oil
Vanadium
turbine
way
that
blades
nickel
–
chemical
and
does.
valves.
symbol
It
V.
Vanadium
shows
up
is
not
a
combustion
often
seen
but
by-product
can
be
a
in
wear
exactly
metal
the
from
same
Titanium
components,
used.
particularly
(dune)
Titanium,
mining
–
chemical
when
springs,
applications.
like,
titanium
symbol
chromium
and
ores
valves.
Ti. may
can
This
It
show
be
may
metal
in
also
up
the
appears
as
environment;
be
aitthe
present
contaminant
as
aof
wearing
iflubricants
ceramic
this
where
is
quite
element
components
dirt
common
entry
in
turbine
has
in
have
mineral
occurred,
been
sand
Cobalt
normally
–
chemical
come
from
symbol
turbine
Co.
components
Cobalt
is
almost
or
as
never
alloy
seen
in
ant-friction
but
ifplain
itmay
does
bearings
appear
with
then
iron.
would
into
gearboxes
coated
all
three
with
as
the
elemental
–
a
chemical
metal.
component
categories.
symbol
of
the
Mo.
synchro
As
Molybdenum
a
wear
rings.
metal
Some
is
itcontain
another
is
engines
most
one
commonly
have
of
those
the
seen
compression
metals
in
automotive
that
can
(top)
fall
ring
It
disulphide
Mo-Di
Molybdenum
moving
is
seen
is
and
an
as
(Mo-Di)
anti-friction
heavily
an
disulphide
additive
is
loaded
an
compound
in
after
can
engine
applications
also
market
be
oils
that
blended
additive
as
has
such
part
been
into
as
than
of
the
dragline
used
gear
can
anti-oxidant
oils
be
in
gearboxes.
added
that
are
package.
to
to
lubricants
for
be
almost
used
Molybdenum
by
a
in
century.
very
the
end
slow
user.
As
package.
may
a
appear
contaminant
It
is
in
also
the
ititsymbol
oil
a
can
component
as
show
grease
up
contamination.
of
in
grease
internal
so
coolant
ifearth
damaged
leaks
seals
as
part
of
allowing
the
coolant
lubricant
additive
transfer
itaisif
Manganese
steels
replacement
combustion
manganese
and
may
by-product
–
exists
in
fuels
chemical
equipment
occur
contain
as
an
in
in
symbol
shafts,
additive.
the
manganese
working
oils
Mn.
valves,
of
in
This
petrol
manganese
as
gears
metal
an
engines
anti-knock
and
is
found
mines
anti-friction
using
as
additive
where
these
an
bearings.
itup
types
so
indicates
itthe
can
of
element
It
fuel.
show
is
dirt
quite
In
entry.
with
very
up
adirt.
as
common
iron
rare
Some
a
in
cases
some
lead
The
ones
following
being
copper,
lead
of
and
wear
tin.
metals
Silver,
are
antimony
all
elements
and
cadmium
plain
bearings,
may
be
seen
the
most
on
rare
common
occasions.
zinc
Copper
contaminant
washers,
component
make
–
worm
chemical
brass.
will
and
contain
gears,
occasionally
Bronze
symbol
sintered
copper.
gears
Cu.
an
Copper
clutch
are
The
additive.
frequently
alloy
packs
of
Copper
many
copper
and
used
brakes.
wear
comes
and
as
worm
metal
tin
Anything
from
is
gears
called
sources
with
in
bronze
bearings,
worm
although
a
whilst
drive
bushes,
it,
metal
gear
copper
too,
boxes.
thrust
and
be
Very
system
does
can
gets
problem.
oil
be
into
high
not
analysis
a
components
the
mean
little
levels
oil
disturbing
report.
that
it
can
copper
the
are
evaporate
Copper
cooler
to
frequently
can
see
can
is
leach
several
off
dissolving
also
made
from
leach
hundred
oil
and
the
coolers
copper
ppm
the
is
not
and
of
water
behind
an
copper
this
radiators
indication
side
can
which
in
of
leach
a
the
as
sample
is
of
a
directly
cooler
an
athat
contaminant.
problem.
indication
suddenly
and
into
ifup
However,
this
of
appear
Cooling
oil.
a
water
This
in
itin
on
seen
newly
as
can
an
assembled
additive.
be
a
component
machinery.
of
some
Like
manganese,
assembly
compounds
in
very
rare
and
circumstances,
may
appear
as
copper
a
contaminant
may
be
Tin
metal
commonly
flashing
chemical
(white
on
found
them;
metal)
symbol
in
this
the
and
helps
Sn.
main
is
Tin
to
and
major
conduct
is
frequently
big
end
heat.
bearings
alloyed
of
a
of
with
plain
engines.
lead
bearing
to
Some
form
overlay.
what
pistons
is
This
known
may
is
have
most
as
Babbit
a
tin
Solder
up.
an
sometimes
additive
Tin
can
also
in
be
seen
some
an
found
alloy
with
specialty
as
of
internal
both
tin
and
a
compressor
wear
coolant
lead
metal
so
leaks;
that
lubricants.
and
any
itan
a
is
soldered
contaminant
not
an
indication
joints
may
on
of
leach
very
a
problem
rare
into
occasions
the
but
oil
ititvery
and
can
ititcan
show
is
plain
clutch
metal.
–
pack
chemical
designs.
(mains
symbol
Brakes
and
Pb.
big
systems
This
ends).
metal
It
can
is
is
also
contain
the
other
found
lead
major
too. bushes
constituent
Some
and
coatings
some
of
more
may
old
metal
contain
fashioned
found
the
in
common
days
may
ppm
a–
show
of
contaminant
itbearings
is
lead
additive
unusual
very
in
the
high
found
to
oil
can
see
levels
per
in
leach
lead
one
petrol
of
lead.
as
kilometer
from
so
a
petrol
As
solder,
itleaving
would
a
traveled.
very
additive
like
end
general
tin,
up
but
from
in
samples
rule
the
the
of
oil
cooling
thumb
coming
a
combustion
itsystem.
can
from
be
across
Lead
reckoned
by-product.
used
our
on
borders
to
be
one
These
a
Lead
gear
products
show
oils
is
very
found
were
are
high
not
as
lead
lead
used
an
based
extreme
anymore.
with
and
pressure
every
However,
same
now
agent
additive.
and
gearboxes
in
again
some
Environmental
a
greases
with
drum
a
twenty
and
the
concerns
many
stuff
year
will
old
years
turn
charge
ago
up.
that
industrial
of
these
oil
may
Silver
is
destroy
based
vitally
–
solder
the
chemical
important
bearing.
used
symbol
to
in
Silver
use
some
a
Ag.
can
zinc
cooling
Certain
be
free
found
systems.
oil
plain
in
in
these
bearings
coatings
applications
and
in
locomotive
quite
as
the
engines
levels
zinc
can
can
attack
leach
contain
the
from
silver.
silver
and
It
Antimony
agent
be
in
alloy
grease
with
lead
so
itsymbol
can
and
end
tin
in
Sb.
up
some
in
Antimony
the
exotic
oil
as
is
plain
a
most
grease
bearings.
commonly
contaminant.
seen
as
In
very
an
extreme
rare
occasions
pressure
itthis
can
Cadmium
bearings
and
–
chemical
some
coatings.
symbol
Cd.
Cadmium
is
rarely
seen
but
italloying
could
be
a'yellow'
constituent
of
plain
Tantalum
Ta.
This
may
be
in
ceramic
materials
but
is
rarely
seen.
Cerium
again,
–
chemical
is
rarely
seen.
Ce. This
is
a
rare
metal
and
is
also
found
in
ceramic
materials
Beryllium
and
important
washers
like
cerium
and
–
in
chemical
jet
trace
aircraft
and
amounts
tantalum
symbol
engine
of
Be. is
oil
the
a
analysis
component
This
metal
is
can
one
as
beryllium
indicate
of
found
first
in
a
ceramic
is
serious
metals
an
alloying
materials.
encountered
problem.
element
It
is
in
in
also
the
certain
very
periodic
thrust
table
Zirconium
As
working
with
in
–chemical
these
chemical
itof
environments.
is
a
symbol
major
constituent
Zr.
of
mineral
is
the
last
sands
of
the
so
ceramic
shows
up
elements
as
dirt
in
that
machines
is
analysed.
Lithium
common
sample
ittitanium
additive
is
a
sure
used
indication
Li.
soap
of
Lithium
grease
(thickening
is
contamination.
only
found
agent)
as
a
many
contaminant.
greases.
The
If
itBabbit
shows
metal
is
up
a
in
an
oil
references
the
operating
cooling
–
pressures
chemical
to
system
internal
can
symbol
and
coolant
leak
temperatures,
Na.
into
leaks
Throughout
the
and
this
water
this
elements
system
technical
evaporates
associated
and
bulletin
contaminate
with
there
them.
have
the
To
oil.
been
re-cap,
Often,
many
at
water
Most
a
damage.
present
indication
variety
cooling
but
of
It
of
chemicals
is
an
systems
these
no
internal
longer
chemicals
should
enabling
coolant
evident.
be
that
the
leak.
treated
The
get
coolant
most
with
behind
common
to
glycol
do
its
in
and
job
the
chemicals
and
a
oil
coolant
and
protect
contain
indicate
conditioner
sodium
cooling
water
which
so
system
this
has
will
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