the natural performance advantage - castrol · cutting the compromise a reliance on the performance...

Best on test neat cutting FLuiD The NaTural PerformaNce advaNTage

eXecutiVe summaRYthe metaLWoRKing sectoR’s neeD FoR high PeRFoRmance neat FLuiDs has Long ResuLteD in an inDustRY-WiDe gRaVitation toWaRDs mineRaL-BaseD PRoDucts.

Flashpoint problems and environmental

responsibility concerns have spurred over

20 years of research and development

into alternative, plant-based chemistries.

But in the absence of formulas that

can deliver comparable performance to

mineral-based fl uids and help enhance

the working environment– at an

attainable cost – OEMs and operators

have found it diffi cult to justify switching

from the status quo. Up to now, the

challenge has always been to produce a

long life plant-based product.

Innovation has come a long way from

the traditional, darker colour, stronger

smelling vegetable fl uids that soon turned

rancid. A gradual move to synthetic

esters has brought us closer to a category

capable of wider market penetration –

though even second and third generation

plant-based fl uids have struggled with

lifespan challenges surrounding oxidation

stability.

With the next generation of plant-

based fl uids now coming to the fore, is

the natural order of things about to be

disrupted?

Proving the problems with premature

breakdown have been overcome and

demonstrating value-add from a total

cost of ownership (TCO) perspective are

key to convincing a sceptical buyer of the

natural performance advantage that can

be achieved with the latest plant-based

fl uid technologies.

This paper, which draws upon industry-

accepted, laboratory-based testing

methodologies, aims to benchmark a

range of widely available mineral-and

plant based metalworking fl uids.

The ultimate objective of this study is

to help those involved in fl uid selection

make more informed and responsible

cutting fl uid choices that impact upon

their working environments, sustainable

performance and operational viability.

cutting the comPRomise a ReLiance on the PeRFoRmance attRiButes oF tRaDitionaL mineRaL-BaseD FLuiDs has histoRicaLLY inVoLVeD ceRtain comPRomises, incLuDing unPLeasant WoRKing conDitions anD unDesiRaBLe eXteRnaL enViRonmentaL imPact.

While plant-derived products have

attempted to deliver an acceptable

alternative, metalworkers have been left

dealing with messy machinery and more

frequent changeovers due to problems

with oxidation stability and related

in-use issues. Indeed, the opportunity to

narrow the performance gap between

mineral-based fl uids at one end of the

spectrum and plant-based fl uids at the

other has proven problematic. However,

a new selection of plant-based grades

from Castrol – Performance Bio NC

fl uids – could help to cut many of the

compromises previously attributed to

so-called ‘biolubes’.

DeFining PeRFoRmance the PeRFoRmance oF a FLuiD in machining can Be BRoaDLY consiDeReD in teRms oF its aBiLitY to enhance PRoDuction.

Whether that is through supporting greater productivity, more precise working or

better quality outputs, cutting and cooling fl uids have a signifi cant impact on overall

factory performance, contributing directly and indirectly to:

Throughput

Fluids that promote faster and longer

working – either due to retained

lubricity and/or more conducive working

environments.

Consistency

Cutting fl uids that run cleaner in machines

and promote precision working to attain a

high quality and/or consistent fi nish.

Flexibility

Fluids that can be ‘performance matched’

to a variety of metalworking applications,

thereby reducing the incidence of fl uid

changeovers, tool replacements and

substitute materials.

Using in-house and industry-recognised

methodologies, the tests were conducted

under controlled conditions by Castrol’s

technical experts in collaboration with

external laboratories. The following

benchmarking tests were performed,

recorded and validated during the period

April-June 2013.

The Rotating Pressurized Vessel Oxidation Test (RPVOT)

A measure of oxidation stability. It works

by stressing the fluid in an oxidating

environment that includes heat, water, a

copper catalyst, pressurized oxygen and

agitation. The deciding factor is the length

of time the fluid can resist these stressing

conditions before the break point is

reached and the fluid degrades (oxidizes).

Flashpoint

Using the standard ‘open cup’ test

method, the lowest temperature at which

the fluid vapour forms an ignitable

mixture in the air was obtained.

testing methoDoLogies muLtiPLe tests haVe Been conDucteD on a Range oF comPaRaBLe mineRaL anD PLant BaseD FLuiDs.

Air Release

Designed to measure how quickly air

bubbles dissipate from fluids, this is an

important performance indicator as the

presence of too much air reduces cooling

and lubricating properties.

Load carrying and anti-wear tests

These tests involve rotating test pieces

and measuring a force or load (in

Newtons) under fixed test conditions.

This information is used to compare the

lubrication properties of various products.

The Tapping torque test is conducted

by cutting or forming a thread into a

pre-drilled hole. This is a test relevant to

certain machine tool applications and is a

measure of how much energy is required

to ‘tap’ a hole. Test results are normalized

and compared to a reference, and the best

result is the sample with the lowest torque.

4-ball testing is used to compare

load-carrying or anti-wear properties of

products to each other. The 4-ball wear

scar test is executed, for an extended time

under a fixed load. The subsequent wear

scar diameters on the balls are measured.

test sites anD Dates BP Italy Turin Technology Centre, Italy (April-May 2013):

Shell 4-ball Test (ASTM D2783/98), Foam Test on Neat Fluids (ASTM D892),

Flash Point (ASTM D 92), Tapping Torque Test

BfB Oil Research S.A., Belgium (May 2013):

RPVOT Oxidation Test (ASTM D2272)

BP Pangbourne Laboratories, UK (May-June 2013):

Air Release Test

Castrol

• Performance Bio NC Super Lite (8 cSt)

Plant-based fluid & synthetic

hydrocarbon blend

• Performance Bio NC Ultra Lite (16 cSt)


hydrocarbon blend

• Performance Bio NC Lite (35 cSt)


hydrocarbon blend

• Performance Bio NC Plus (40 cSt)

Plant fluid

PRoDucts anD categoRisation the FoLLoWing DescRiPtoRs WiLL Be useD thRoughout the RemainDeR oF the PaPeR.

• Variocut G 600 HC (8 cSt)

Mineral-based fluid

• Variocut G 613 HC (13 cSt)

Mineral-based fluid

They apply to a group of 10 individual fluids available on the open market from

Castrol and other well-known fluid suppliers. The specific viscosity index of each

product is provided in brackets:

For the purpose of comparing each product appropriately, please refer to the viscosity bands in the following table.

Green text and bar charts indicate a plant or plant-based product, while black text and bar charts illustrate a mineral-based fluid:

Brand A

• Plant fluid A (40 cSt)

• Plant-based fluid A (22 cSt)

Brand B

• Plant fluid B (35 cSt)

Brand C

• Mineral-based fluid C (15 cSt)

Low (5-9 cSt)

Medium-low (10-16 cSt)

Medium-high (20-30 cSt)

High (35-40 cSt)

Performance Bio NC Super Lite

Variocut G 600 HC

Performance Bio NC Ultra Lite

Variocut G 613 HC

Mineral-based fluid C

Performance Bio NC Lite

Plant-based fluid A

Performance Bio NC Plus

Plant fluid A

Plant fluid B

Overcoming the oxidation stability challenge

• Performance Bio NC Plus and NC Lite

are markedly more stable than the other

plant-based fl uids on test.

• Performance Bio NC Super Lite and NC

Ultra Lite now provide operators with

the same level of oxidation stability as

mineral-based fl uids

• Variocut G 600 HC shows the best

oxidation stability results overall.

Oxidation stability is an important attribute

from a performance standpoint because

a composition that degrades more slowly,

performs for longer. Retained lubricity

reduces wear on tools, thereby maintaining

the precision and quality of the fi nish

for longer.

Less frequent changeovers also mean

less downtime. In the past, plant-based

products have struggled to achieve the

same levels of stability as their mineral-

based counterparts. Coupled with

this, plant-based fl uids have become

synonymous with messy fl uid breakdown,

prohibiting widespread worker acceptance.

The results attributed to Performance

Bio NC Ultra Lite and Super Lite indicate

that these issues have been largely

overcome and there is now a plant-based

alternative to mineral-based fl uids in terms

of oxidative stability. The advantage of

using a high viscosity Performance Bio

NC fl uid is even more marked, according

to the oxidation data, with up to 50%

improvement over the next best,

plant-derived fl uid.

Test 1: Oxidation stability via RPVOT

Brand A: Plant fl uid (40 cSt)

Brand A: Plant-based fl uid (22 cSt)

Brand B: Plant fl uid (35 cSt)

Performance Bio NC Lite (25 cSt)

Performance Bio NC Plus (40 cSt)

Variocut G 613 HC (13 cSt)

Performance Bio NC Super Lite (8 cSt)

Performance Bio NC Ultra Lite (16 cSt)

Brand C: Mineral-based fl uid (15 cSt)


0 20 40 60 80 100 120 140 160 180 190 200

Oxidation Onset Time (minutes)

Higher fl ash points; lower risk

• The highest viscosity Performance Bio

fl uid (NC Plus) has the highest fl ashpoint

of the plant-based fl uids tested

• Plant-based formulations, with high

viscosities are safer, with fl ash points

surpassing 200°C

For all the performance merits of mineral-

based fl uids, relatively low fl ash points

have long presented a problem for those

specifying such lubricants. Fires can occur

in metalworking environments when

fl uid fl ow is unable to moderate the

temperature of the workpiece. These

incidents are relatively rare; so many

Test 2: Flash point











0 50 100 150 200 250 300 350

Temperature (°C)

manufacturers don’t tend to see this as

an overriding concern. However, factor in

the time spent dealing with fl ammability

issues, insurance risks and employee safety,

and the impact on productivity and staff

wellbeing could be notable.

With a fl ash point of 296°C, under

laboratory conditions, it is clear the natural

choice when it comes to fl ash point safety

is Performance Bio NC Plus. However, for

an excellent combination of oxidation

stability and fl ashpoint, OEMs should

consider NC Ultra Lite, depending on

operating temperatures and application.

Faster air release delivers record results

• Performance Bio NC Plus separates

entrained air almost 20 times quicker

than a competitive plant-based product

with similar viscosity (Brand A: plant

fl uid 40 cSt)

A mixture of air and fl uid circulating

through the lubrication system often

results in impaired performance due to

reduced cooling and lubricating properties.

Mineral-based fl uids tend to offer better

results in this respect and so harnessing

comparable features from a plant-based

product represents signifi cant advances in

fl uid technology.

Performance Bio NC Plus presents

OEMs with an excellent plant-based

option for mitigating against entrained

air under operating conditions. In our

laboratory, dispersal rates for this product

outperformed all other fl uids on test.

NB: No results are available for

Performance Bio NC Super Lite.

The volatility of one of its components

meant that no data could be recorded

under the conditions of the test.

Test 3: Air release










0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Time (minutes)

Extended tool life enhances product fi nish

• Higher viscosity fl uids performed best

on test, with Performance Bio NC Plus

delivering the most impressive results

• Mineral-based blends, in general, gave

higher torque values in this test

Test 4: Load Carrying – Tapping torque











0 20 40 60 80 100 120 140

Torque (ncm)

Lower torque values are preferable

under the conditions of the test because

tool life benefi ts and/or surface fi nish

improvements can be achieved. Here,

Performance Bio NC Plus – again – is the

best overall performing fl uid with 7% less

torque required than the highest rated

alternative.











0 0.2 0.4 0.6 0.8 1 1.2

Scar diameter (mm)

Test 5: Load Carrying – 4-ball

Excellent wear prevention

• Brand C’s mineral-based fl uid displays the

strongest properties in this wear test due,

in part, to its anti-wear additive content

• Performance NC Lite, Ultra Lite and

Super Lite display excellent wear

prevention, which underscores the

fl exibility of Performance Bio NC fl uids

across multiple viscosities

This metal-on-metal load test also

measures the lubricity properties of each

fl uid. A low number indicates good

performance (i.e. a low level of wear)

which, by association, can have a positive

bearing on tool wear and fi nish quality.

The results demonstrate that all

Performance Bio NC products perform well

under the test conditions.

Best overall performance

• Performance Bio NC Plus is the overall

‘best on test’ fl uid

• Performance Bio NC Plus outperforms

all other fl uids tested on fl ash point, air

release, tapping torque and evaporation

• Performance Bio NC Plus also achieves

good to excellent scores on the

remaining criteria: oxidation and

anti-wear properties

Consistency: Higher fi nish quality and accuracy

The data suggests that Performance

Bio NC products can offer comparable

performance to mineral-based fl uids, but

with cooler running temperatures, which

reduce problems of heat generation

affecting fl uid stability, and in turn,

workpiece quality and appearance.

Machinists may also encounter fewer

metal staining problems.

The following chart shows the median score of each fl uid, relative to the number of tests each product completed (i.e. not all

10 products completed all 7 tests). In each instance, the products were attributed a score 1-10 refl ecting their results ranking.

So, the best performing fl uid was allocated a maximum 10/10; while the worst ranking products would receive only 1/10.

A high number indicates superior performance across most test criteria:

oVeRaLL PeRFoRmance anD KeY taKeaWaYs

Throughput: Improved speed and lower downtime

Through the use of Performance Bio

NC fl uids, operators may be able to

increase running or rotational speeds

while minimising mist and fl ashpoint

hazards. Manufacturers could benefi t

from higher throughput and productivity

improvements due to the ability to run

at higher speeds, which can reduce

downtime between jobs and extend

machine cycles.

Flexibility: Fewer interruptions, more choice

The versatility of the Performance Bio NC

products means they can be used on a

wide variety of metals and different cutting

tasks, reducing the need for changeover

between different fl uid types. Customers

specifying such fl uids may therefore enjoy

fewer interruptions to operations, more

tool and metal choices, plus a reduction

in product inventories.







Brand C: Mineral based fl uid (15 cSt)

Variocut G 600 HC (8cSt)



0 2 4 6 8 10

Total score (average across all tests)

Performance characteristics

Excellent cutting performance Lower mist Low smoke Improved stability

Primary benefits

Better tool life, higher-quality finish

Reduced consumption, improved working environment

Improved flammability, better tool life/productivity

Lower maintenance, more reliable performance

NC Plus Cast iron

Low-medium alloyed steel

High alloyed steel/nickel-

chromium alloys

Titanium alloys

Aluminium alloys

Yellow metals

Honing / Superfinishing

– – – – – –

Grinding – – – – – –

Drilling ** * – * ** *

Broaching * * – ** ** **

Gear manufacturing

** ** * ** ** **

General machining

** ** * ** ** **

NC Lite Cast iron



chromium alloys

Titanium alloys

Aluminium alloys

Yellow metals


* ** * * ** **

Grinding * * * * * *

Drilling * * – ** ** **

Broaching * * – ** ** **

Gear manufacturing

** ** – ** ** **

General machining

** ** – ** ** **

For a more detailed breakdown of the four Performance Bio NC fluids, please refer to the tabulations below.

Performance Bio NC Product Applications

** suggested application * possible application (please refer to Castrol representative prior to use)

in Focus: PeRFoRmance Bio nc

NC Ultra Lite Cast iron



chromium alloys

Titanium alloys

Aluminium alloys

Yellow metals


* * * * ** **


Drilling ** ** – ** ** **

Broaching * * – ** ** **

Gear manufacturing

** ** – ** ** **

General machining

** ** – ** ** **

NC Super Lite Cast iron



chromium alloys

Titanium alloys

Aluminium alloys

Yellow metals


** ** * ** ** **


Drilling * – – – ** **

Broaching – – – – ** **

Gear manufacturing

– – – – ** **

General machining

– – – – ** **

DRiVing a natuRaL aDVantage FRom Within castRoL’s neW cLass oF PeRFoRmance Bio nc FLuiDs giVes manuFactuReRs moRe choice When it comes to maKing ResPonsiBLe FLuiD seLection.

By looking to achieve a better balance

between factors such as performance,

value, safety and the operating

environment, this latest fluid technology

will help customers cut the compromise

on the factory floor.

Castrol sees the challenge that industry

faces and has turned it into an opportunity

to move forward together. The result is

Castrol Performance Bio NC fluids.

PeRFoRmance Bio get a natuRaL aDVantagewww.naturaladvantage.castrol.com

the natural performance advantage - castrol · cutting the compromise a reliance on the performance...

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