Cemented Carbide, Sandvik new developments and applications

2

A key feature of the material is the

potential to vary its composition so that the

resulting physical and chemical properties

ensure maximum resistance to wear,

deformation, fracture, corrosion, and

oxidation. In addition, the wide variety of

shapes and sizes that can be produced

using modern powder metallurgical

processing offers tremendous scope to

design cost effective solutions to many of

the problems of component wear and

failure encountered in both the engineering

and domestic environment.

Engineering MaterialsThe most commonly used materials are

shown schematically relative to their

hardness and toughness properties.

Diamond (PCD) is the hardest, of all,

followed by Cubic Boron Nitride (CBN) and

the Ceramics (Al2O3, SiC, SIALON etc). The

superhard materials all suffer from lower

toughness and poor resistance to sudden

fracture, the Cemented Carbides have a

unique combination of high hardness and

good toughness within a wide range and

thus constitute the most versatile hard

materials group for engineering and

tooling applications.

A unique materialCemented Carbide is one of the most successful compositeengineering materials ever produced. Its unique combinationof strength, hardness and toughness satisfies the mostdemanding applications.

This brochure has been produced to give

engineers a basic understanding of the

unique properties of cemented carbide.

Experience shows that the most effective

product design results from close cooperation

among engineers representing all the

disciplines related to the particular

application.

This approach is especially recommended

when Cemented Carbide is to be used.

The data and graphs shown in this brochure

represent typical values from laboratory

tests and provide an insight into the design

characteristics of the material. Specific

recommendations regarding the selection

of actual grades for any new application

can be made only on the basis of tests and

experience.

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The proportion of carbide phase is normally

70 % to 97 % of the total weight of the

composite and its grain size averages

between 0.2 µm and 20 µm. Tungsten

Carbide (WC), is the most common hard

phase, and Cobalt (Co) alloy, the most

common binder phase. These two materials

The Cemented Carbides are a range of compositematerials, which consist of hard carbide particles bondedtogether by a metallic binder.

Types of Cemented Carbide

form the basic cemented carbide structure

and grades based on this concept are often

referred to in simplified terms as Straight

grades. From this basic concept, many

other types of Cemented Carbide have

been developed. Thus, in addition to these

simple WC-Co compositions, Cemented

Carbide may contain varying proportions

of Titanium Carbide (TiC), Tantalum

Carbide (TaC) or Niobium Carbide (NbC)

and others. These carbides are mutually

soluble and can also dissolve a high

proportion of Tungsten Carbide. In addition,

Cemented Carbides are produced that

have the Cobalt binder phase alloyed with,

WC

-gra

in s

ize,

μm

Cobalt content, % by weight

Oil&Gas drillingand mining,

Mineral andground tools

Rolls

Metal formingand Can Tooling

WoodWorking

WireDrawing

CompositeMachining

MetalCutting

5 10 15 20 25 30

0.5

1

2

3

4

5

10

20

Hardness, Hv3 (HRA)

22002000(94)

1800(93)

1600(92)

1400(90)

1200(88)

1000(86)

800

The application range of straightgrade Cemented Carbides.

or completely replaced by, other metals

such as Nickel (Ni), Chromium (Cr), Iron

(Fe), Molybdenum (Mo), or alloys of these

elements.

Thus, three individual phases may make

up a Cemented Carbide. In metallurgical

terms, the Tungsten Carbide phase (WC) is

referred to as the �-phase (alpha), the

binder phase (i.e. Co, Ni etc.) is the �-phase

(beta), and any single or combination of

other carbide phases (i.e. TiC, Ta/NbC etc)

is the �-phase (gamma).

The Cemented Carbide grades developed

by Sandvik fall into three main groups, as

described on the following pages.

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Types of Cemented Carbide

WC-Co gradesThe grades in this group contain WC and

Co as the main elements, although small

additions or trace levels of other elements

are often added to optimize properties.

These grades are classified according to

their Cobalt content and WC grain size and

are often called the "straight grades". They

have the widest range of strength and

toughness of all the Cemented Carbide

types and this is in combination with

excellent wear resistance. This range of

Cemented Carbides can be subdivided into

its major application areas as follows:

Nano, Ultrafine and Submicron gradesGrades with binder content in the range of

3-10 wt% and grain sizes below 1 µm have

the highest hardness and compressive

strengths, combined with exceptionally

high wear resistance and high reliability

against breakage. These grades are used in

a wide range of wear parts applications

and in cutting tools designed for metallic

and nonmetallic machining for which a

combination of high strength, high wear

resistance and sharp cutting edges are

essential.

Fine and Medium gradesThe grades with binder contents between 6-

30% and grain sizes of 1-3 µm are used in

wear parts and cutting tools when an

element of improved strength and shock

resistance is required.

Medium Coarse, Coarse andExtra Coarse gradesGrades with binder contents between 6-15

wt% and grain sizes above 3µm are used in

oil & gas and mining applications where

resistance to high impact stresses and to

abrasive wear are required.

Nano Ultra Fine Submicron Fine Medium Medium Coarse Coarse Extra Coarse< 0.2 µm 0.2 - 0.5 µm 0.5 - 0.9 µm 1.0 - 1.3 µm 1.4 - 2.0 µm 2.1 - 3.4 µm 3.5 - 5.0 µm > 5.0 µm

Sandvik has a sub-micron WC grain size. It is thebenchmark for leading edge wet drawing of tirecord wire.

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Ultrafine GradesWhen reliability is the king – at 300.000 rpm

– Sandvik Hard Materials has supplied high

performance Cemented Carbide Blanks to

toolmakers in the printed circuit board (PCB)

industry since 1983. During 1986-88 the ultra-

fine grades (UF grades) were developed and

introduced in the market. The ultra-fine

grade family boosted our customers’

productivity and became the market-

leading material for tools in the PCB industry.

Today the trend is towards miniaturization:

digital cameras, lap-tops and mobile phones

are becoming even smaller and are

expected to include more features. This has

resulted in more complex printed circuit

boards with a greater number of

components per surface area. To meet this

demand, PCB manufacturers are compelled

to drill more and smaller holes.

This shift in drill size has increased the

demands on tool material. The smallest drill-

diameter today is only 10-20 µm. To facilitate

the use of tiny drills and raise productivity,

spindles with increasing rpm are being

developed. It is now possible to purchase a

standard PCB NC-machine with a maximum

speed of 300,000 rpm.

To satisfy this new demand from customers,

Sandvik Hard Materials decided to develop

and introduce three new grades for PCB

tooling during 2004.

Ultrafine GradesToday the trend is towards miniaturization: digital cameras, lap-tops and mobilephones are becoming even smaller. To meet this demand, Printing Circuit Boardmanufacturers are compelled to drill more and smaller holes.

Sandvik S870 and S880 are a new

generation of grades that have been

specifically developed for PCB drilling

applications. These grades have been

developed through an extensive research

program, that utilizes an entirely new

patented Cemented Carbide processing

technology. The new process optimizes

reliability, toughness and wear resistance.

Sandvik S870 and S880 exhibit exceptional

performance when sharp edge profiles plus

high wear resistance, toughness and

stiffness are required.

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Leading edge carbide technology for rottary cutting applications

Reliability is often a question of wear resistance, and this is the most outstanding feature of

Cemented Carbide. When the tool must also withstand deformation and high pressure,

Cemented Carbide materials are the only alternatives capable of meeting these

requirements.

Since the performance of a cutting edge depends considerably on these properties,

Sandvik designed the new CRC concept (Carbide Rotary Cutters) with a grade tailored to

fulfill the specific requirements. In order to get sharp cutting edges after grinding and no

chips during use, a controlled fine grain size of the hard phase was developed. The binder

(composition and amount) was also optimized to give that excellent micro toughness

required for this applications.

The combination of the hard phase and binder phase results in a grade with the

appropriate properties. This primarily entails high hardness (to lower the wear of the

cutting edge), high micro toughness (to maintain edge-line integrity and perfect cutting),

very high stiffness (to lower the bending of the cutter and flattening of the cutting edge)

and good thermal conductivity (to reduce temperatures during processing).

The leader in Submicron Cemented Carbides

Sandvik has a long standing leadership in

Submicron Cemented Carbide grades. This is

best exemplified by our grade H10F which

has been the leading grade for a wide range

of cutting applications such as end milling,

drilling, band sawing and paper cutting.

H10F is also our example of Sandvik’s

philosophy of continuous improvement. Raw

materials, powder processing and sintering

conditions have been developed to further

improve H10F’s leading performance.

Submicron gradesSharpness and toughness

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Coarse gradesSandvik manufactures a large variety of inserts usedin extreme drilling and percussion conditions

In today's competitive oil & gas drilling

environment, the pursuit of faster,

economical and superior wells has

conjured a host of technological advances.

However, in the end, it all comes down to

the drilling bit.

Cemented carbide is an ideal material for

drilling inserts due to its high hardness,

compressive strength and thermal

conductivity. R&D within Sandvik Hard

Materials has taken these properties and

used novel techniques to improve the

toughness and impact resistance, whilst

reducing the risk of thermal effects of the

inserts during drilling.

The variety of material that Sandvik can

supply, gives a good coverage of all type of

application needs, for soft rock/heat

generation formations, generally go for the

extra coarse and high binder content. This

results in high fracture toughness and

prolonged insert bit life. For hard formations

is generally use medium coarse and low

binder content grades. This results in high

hardness (better abrasion resistance), but

low fracture toughness has a higher

penetration rate but is more likely to

fracture.

Sandvik manufactures a large variety of

inserts used in rotary & percussion rockbits

for oil & gas and mining industries. Extreme

drilling conditions, whether rotary or

percussion or down the hole require novel

solutions and Sandvik has the technology

to supply the customers with inserts that

perform every time.

Compressive strength rises with decreasing binder content and

smaller grain size. A carbide grade with a small WC grain size and

a low binder content has a typical compressive strength

approaching 7,000 N/mm2.

Like all engineering materials the mechanical strength of Cemented

Carbide is reduced at elevated temperatures. This drop in strength

becomes more significant at temperatures above 600 ºC.

For use at elevated temperatures, grades with cubic carbides and/or

alloyed binder are recomended.

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One of the most useful properties of Cemented Carbide is its extremely high compressive strength.

Mechanical properties of straight WC-Co grades

Relative transverse rupture strength as a function of the temperaturefor an 11% Co, medium WC grain size cemented carbide.

Relative hardness at different temperatures.

Compressive strength as a function of the Co content for different WC grain sizes.

Compressive strength as a function of the temperature for13% Co, coarse grain size carbide.

The main properties used to characterizes, the mechanical properties

of cemended carbide are hardness, transverse rupture strength and

fracture toughness.

The graphs on this page show that hardness increases with

decreasing grain size and binder content. Unfortunately, this will

always be at the expense of reduced toughness. In truly abrasive

applications, hardness is a good measure of wear resistance.

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Hardness as a function of the Co content for various WC grain sizes. Wear resistance as a function of hardness (ASTM B611-85).

Fracture toughness as a function of the Co content for different WC grain sizes.

Wear resistance as a function of the Co content with differentWC grain sizes according to the ASTM B611-85 test method.

Corrosion resistant grades

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This group contains CementedCarbide grades in which thebinder phase has beenspecifically designed to raisecorrosion resistance to a levelexceeding that of the gradesthat contain Co alone as thebinder phase.This is achieved by alloying Cowith elements such as Nickel(Ni) and Chromium (Cr), orcompletely replacing it with amore corrosion-resistant alloy.

The susceptibility of the binder phase of

Cemented Carbides to wet corrosion can

result in wear problems. Corrosion

mechanisms give rise to surface depletion

of the binder phase, permitting the carbide

grains to become detached relatively

easily by the wear process. Awareness of

this situation is important to the selection of

the correct Cemented Carbide for a

particular application.

Cobalt is unsuitable as a binder phase in

wet corrosion conditions. Sandvik has

developed a series of highly corrosion-

resistant grades for these applications.

As illustrated, straight WC-Co grades are

corrosion resistant down to pH 7. This is also

valid for WC-Co grades containing �-phase

(i.e. TiC, TaC and NbC). The highest

corrosion resistance is obtained for the TiC-

Ni grades, which are resistant down to pH1.

However, compared with the straight WC-

Co grades, they have low strength and

inferior thermal conductivity. In addition,

they are difficult to grind and have poor

brazeability, and thus they are used only

when corrosion resistance requirements are

high, combined with low demands in terms

of mechanical strength and thermal shock

resistance.

In most corrosion-wear situations, an

optimum choice are the WC-Ni grades,

which are resistant down to pH 2-3. These

grades retain WC as the hard phase, and

substitute Co for Ni; thus they exhibit

mechanical and thermal properties similar

to the WC-Co grades.

PH value is the most important parameter

when determining the corrosivity of the

environment. However, other factors have

an influence, such as the temperature and

electrical conductivity of the medium. The

latter is dependent on the ion concentration,

meaning the amount of dissolved salts in

the solution. Thus, the ranking of the

corrosivity of an environment is never

certain and, accordingly, general rules are

not valid for all situations.

The Sandvik datasheet “Cemented Carbide

Selection for Corrosion Resistance” is

available as a guide.

It is always recommended that tests be

carried out under actual working conditions

before final selection is made.

Corrosion resistance gradesThe binder phase has been specifically designedto raise corrosion resistance

Corrosion rate as a function of the pH value fordifferent types of cemented carbide tested inbuffered solutions. These tests include a finalsurface wear treatment by tumbling in order toobtain a true value of the depth of the corrodedsurface zone.

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Much of the equipment used in the Oil

& Gas industry is subject to an

aggressive environment that must

not only resist erosion from high

velocity fluids containing sand

particles and other abrasive

media, but it must also be resistant

to corrosion damage. The

combination of these two factors has

caused this industry to migrate

towards using more components that

are made from Cemented Carbide. These

components have natural properties that

tend to resist such wear mechanisms;

however, Sandvik Hard Materials has

dramatically improved the resistance to

erosion and corrosion by focusing on the

binder phase of grades used in this field.

In order to improve the wear characteristics

of the Cemented Carbide grades used

specifically for choke valves in this

industry, multi binder (Ni, Cr, Mo, and Co)

corrosion-erosion resistant materials were

introduced. Today, there are more than

100 choke control valves in service using

Corrosion resistant gradesHave contributed to an improvement of up to 5 timesservice life compared to conventional grades

The first choice material in hostile environments

these Cemented Carbide grades operating

in sub-sea and other extreme environments.

These materials have contributed to an

improvement of up to 5 times service life

when compared to conventional grades.

Sandvik Hard Materials has now taken this

performance increase to another level.

Based on feedback gained from the field

and the experiences of equipment design

engineers working with these grades,

Sandvik has carried out development work

focused on improving material toughness

and strength. Success has been achieved

by carefully optimizing the relationship

between wear (material hardness) and

toughness for the multi-binder materials

without any loss of resistance to corrosion-

erosion.

As a result, Sandvik has developed the next

generation of multi-binder grades, such as

AM12.

As always, tests have been carried out with

an industry partner to verify the increased

performance.

DZ10An outstanding performance compared to standard grades to produce both aluminium and steel cans

Failure mechanism of classical WC-Co

carbide punches used for production of two

piece beverage cans by Draw and Wall

Ironing is mainly due to leaching of the

binder phase. DZ family grade (sub-micron

carbide grains combined with the

appropriate binder) has been tailored to

fulfill the specific requirements of the can

tooling industry. This means a material

with very high wear and corrosion

resistance. The shift from the classical

grade used in the field to the specific DZ10

grade has brought many valuable

improvements. Life times have been tripled

and wear reduced, allowing more regrinds

per punch.

After 19 million cans a wear of 0,002 mm

(.0000079") was found for the DZ10 punch

while 0.007 mm (.0000275") was found for

standard grades after only 14 million cans.

Another example of profitable cooperation

between Sandvik and our key customers.

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Cubic and Cermet grades

Cubic and cermet grades are one of the

latest developments for Sandvik Hard

Materials. This group consists of grades

containing a significant proportion of

�-phase, (i.e. TiC, TaC, NbC etc.) together

with WC and Co.

The main features of the �-phase are good

thermal stability, resistance to oxidation

and high temperature wear. These grades

are designed to provide a favorable

balance of wear resistance and toughness

in applications that generate high

temperatures and entail close contact with

ferrous materials. These conditions arise in

metal cutting or high-pressure sliding

contact situations involving the welding

and galling of surfaces.

Saw tips made from Sandvik’s Cermet

grade CE01 for metal sawing/ metal

cutting are designed especially for saws

that do not use coolants. The working

material – conventional and low

carbon steels–interacts with the saw tips

in different ways during extreme

working conditions.

The Cermet grade CE01 offers high

oxidation/ corrosion resistance to

maintain edge sharpness. To ensure

edge retention during sawing, high

wear resistance plus high toughness

are of crucial importance for the

Cermet CE01 tips. Brazeability and

grindability also are key properties

when manufacturing saw blades.

Cermet CE01 tips are surface-treated to

maintain optimal surface conditions for

brazing and a high micro-toughness

for good grindability.

Other common terms for these grades are

the “metal-cutting” or “mixed-crystal” grades.

In the extreme case, these grades are

designed without any WC phase. Such

hard metal grades are called cermets and

give a unique combination of high

temperature hardness, chemical wear

resistance and low density. Cermets are

traditionally avoided for wear parts because

of being more brittle than standard WC-Co

grades. New developments have allowed

toughness to be improved significantly

and cermets are now applied in a number

of demanding applications from advanced

engineering components to high perfor-

mance metal sawing blades.

WC-Co Cubic Cermet

Optimized performance at extreme working conditions

Sandvik Hard Materialsexperience Cubic and Cermet grades

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Challenging the futureTailoring solutions to a wide variety ofautomotive applications

Sandvik Hard Materials has been

developing and supplying solutions for the

automotive industry for over two decades.

Our extensive knowledge of cemented

carbide and related cermets allows us to

tailor solutions to a wide variety of

automotive applications. Our components

are incorporated into systems used world-

wide by the leading automotive companies

and suppliers.

One example of how our materials

challenge the conventional thinking is our

unique ability to produce components that

fullfill all technical requirements while

being only a fraction of the size of a similar

component produced in steel.

Cemented carbide is commonly perceived

as a cutting tool or wear part material.

While cemented carbide is ideally suited for

cutting and wear applications limiting your

view to only these areas is far too

restrictive. In reality, cemented carbide

and cermets offer a wide range of

properties making them very well suited for

the new challenges of the automotive

industry.

The four steps toward the final cemented carbideproduct: powder composition, powder compacting,sintering and machining/grinding.

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Research and development in Cemented CarbideFrom raw material to your needs, Sandvik develops Cemented Carbide technology to meet our present and future customer needs.

From atomic engineering of crystal grain

boundaries to the customer-specific design

of a rotary cutting station; Sandvik

Research and Development is dedicated to

advancing the frontiers of cemented

carbide technology in order to meet our

customers’ present and future needs. Every

stage in the manufacture of a cemented

carbide component – from powder

production to finishing – is crucial to

Our peopleSandvik employs around 150 engineers,

technologists and technicians at centres in

Sweden, the UK and France, dedicated to

R&D of hard materials.

These people work closely with our

customers through our global product-

specialist networks to ensure our R&D is

focused on application and customer

requirements. The application know-how

gained through these networks in key

business areas enables us to work together

to create the best materials for each

application.

General Notes/Recommendations:The properties and data listed in this brochure represent average values based on laboratory testsconducted by Sandvik. They are indicative only of the results obtained in these tests and should not beconsidered as guaranteed values. Any statements in this brochure referring to a specific alloy for aparticular application, or to the use of a product, are solely recommendations based on tests or experience.Such statements cannot be considered as warranties/guarantees. Products, and any recommendedpractices, should always be tested by the user, under actual service conditions, in order to confirm theirsuitability for an application.

ensuring optimum performance.

At Sandvik, we take pride in having full

control of each processing step and in

developing proprietary production

processes that further improve our

technological capabilities. Our mission is to

develop new products and new grades

that enhance our customers’ operations

through superior performance and reduced

costs.

15

Our performance

Although it is more than 80 years since the

first cemented carbide material was

marketed, the pace of development in the

field remains rapid. Sandvik is at the

forefront of this development, issuing 20 to

30 cemented carbide-related patents and

releasing 5 to 10 new grades with

improved performance every year.