diabond

Diabond 2000, Verona 25/26 September

Key Factors in the Performance of Sintered Diamond Tools for Stone Sawing

L. Risso, M. Pareto, M. Capurro*, L. Gaggero§

Centro Sviluppo MaterialiCorso Perrone 24/aI-16152 GenovaItaly

*DEUIM, University of GenoaP.zale Kennedy, Fiera del Mare, Pad. DI-16127 GenovaItaly

§DIPTERIS, University of GenoaCorso Europa 26I-16132 Genova


STONE

DIAMOND ALLOY

•COMPOSITION

•PETROGRAPHY

•MECHANICAL PROPERTIES

•COMPOSITION

•MICRO-STRUCTURE

•MECHANICALPROPERTIES

•FRIABILITY

•COMPRESSIVESTRENGTH

•STATISTICS

•GANULOMETRYANDMORPHOLOGY

•COLOUR

•INCLUSIONS

•THERMALSTABILITY

•Sawability •Abrasivity

•Retention

•Concentration

PERFORMANCE


NF

T

PP

NIT

ln

..

Toughness indexToughness index

It is conventionally assumed that N is the number of cycles such that PNF= 0.5PT


(*) average value of dispersed results

Measure of TI and TTI for Measure of TI and TTI for different materialsdifferent materials


Crushed grain distribution (mesh)Crushed grain distribution (mesh)


Friabilty of Diamond Mixtures

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

Fraction

F.I.

of

the

Mix

ture

Fi=10; Fj=20

Fi=10; Fj=30

Fi=10; Fj=40

Fi=10; Fj=50

Fi=10; Fj=60

Fi=10; Fj=70

Fi=10; Fj=80

Fi=10; Fj=90

Fi=10; Fj=100

Fi=10; Fj=110

Fi=10; Fj=120

Fi=10; Fj=130

Fi=10; Fj=140

Fi=10; Fj=150

5.0)5.0()5.0()()( Fj

F

Fi

F

P

Pj

P

Pi


Geometrical parameters of the Geometrical parameters of the modelmodel

rr

33


Convergence of Mean Stress and Standard Deviation (SDB 1085)

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60

Number of Data

Me

an

Va

lue

s (

MP

a)

Average of MeanStress

Average ofStand. Dev.


)(1)( cNf eP

Weibull statisticsWeibull statistics

Where Nc is the mean number of defects responsible for fracture at a stresses

dVnNEV

c )()(


n() at different Weibull modulus value

0

0,2

0,4

0,6

0,8

1

0 0,2 0,4 0,6 0,8 1

n(

)V0

m=0

m=

100

m

Vn

00

1)(




With the hypothesis of uniform defects distribution ((V)) we obtain:

mE

V

V

f eP

00)(1

and therefore

)ln(ln)(1

1lnln

00

mV

V

P mE

f



F )(fP

i1ni

n is the number of tests and 1 ii

)ln(

)(1

1lnln

fP

m1

m2

m3

m1=m2>m3


Wibull Plot on SDB 30/40

y = 1,7718x - 11,842

y = 3,3019x - 23,364

y = 4,1235x - 29,762

y = 3,5792x - 25,24y = 2,4914x - 17,276

-4

-3

-2

-1

0

1

2

4,5 5 5,5 6 6,5 7 7,5 8

Ln()

Ln

(Ln

(1/(

1-p

f)))

1055

1075

1100

1085

1065

Lineare(1055)Lineare(1075)Lineare(1100)Lineare(1085)Lineare(1065)



Compression DataCompression Data

Hard Metal Anvils

400

500

600

700

800

900

1000

1100

1200

1300

1400

1055 1065 1075 1085 1100

Diamond class (30/40 mesh)

2000

2500

3000

3500

4000

4500

5000

5500

6000

Mean Strength (N)

Mean Stress (MPa)

Mean Strength on Section (MPa)

Log. (Mean Strength on Section (MPa))

Log. (Mean Strength (N))

Log. (Mean Stress (MPa))


Weibull Mudulus DistributionWeibull Mudulus Distribution

Hard Metal Anvils

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

1055 1065 1075 1085 1100

Diamond class (30/40 mesh)

We

ibu

ll M

od

ulu

s

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

Weibull Modula for Stress

Weibull Modula for Strength on Section

Potenza (Weibull Modula for Strength on Section)

Potenza (Weibull Modula for Stress)


Effect of Anvil MaterialEffect of Anvil Material


A

DiamEq4

..

)(PMaxMaxFeret

)(PMinMinFeret

13590450

4

PPPP

AMeanChord

MinFeret

MaxFeretElongation

2)(

4

Perimeter

AyCircularit

P

Geometrical ParametersGeometrical Parameters

A


Different inclusion morphology in Different inclusion morphology in SDA (B) and SDB (A) diamondsSDA (B) and SDB (A) diamonds


<100> direction

<111> direction

(100) planes

Typical inclusion distribution in a Typical inclusion distribution in a SDA family diamondSDA family diamond


Thermal Stability: Combustion Thermal Stability: Combustion TemperatureTemperature


Hardness of Different Stones With Hardness of Different Stones With Similar CompositionSimilar Composition

Quartz dimension: 0.1-0.2 mm Quartz dimension: 0.2-1.5 mm


White Finale White Marble (Carrara)

2.5 mm


Cobalt PropertiesCobalt Properties

Effect of ageing (2 h) on hardness Effect of alloying (1 at.%) on transition


Mixture PropertiesMixture Properties


Hardness of a Mixture Co/WC

300

320

340

360

380

400

420

440

0 0,05 0,1 0,15 0,2 0,25 0,3

WC Volume Fraction

HV

30 WC >> 1 micron

WC = 1 micron

WC << i micron

Mixture PropertiesMixture Properties

Co

Co

WC

WC

CoWC H

V

H

V

H

/

1


Cu/Sn Phase diagramCu/Sn Phase diagram


Abrasivity Measurement Abrasivity Measurement


Loss of volumeMarble at 500 rpm

0

0,005

0,01

0,015

0,02

0,025

0,03

0,035

0,04

0,045

0,05

0 20000 40000 60000 80000 100000 120000 140000

meters

Vo

lum

e L

ost

(cm

3 )

Bronze

Bronze+Cobalt

Bronze+cobalt+WCCobalt A

Cobalt B

Cobalt+WC

Abrasivity Measurement Abrasivity Measurement


Sawability Measurement Sawability Measurement


0

50

100

150

200

250

300

350

400

0 8 16 24 32 40

Time [h]

We

ar

[m

]

0

1

2

3

4

5

6

7

8

9

10

To

rqu

e [

Nm

]

Wear B3M

Wear B4M

Torqe B3M

Torque B4M

Sawability Measurement Sawability Measurement


We want to acknowledge •De Beers Industrial Diamond Division for providing the samples

•Italian Ministry for University and Research for partial funding

AcknowledgementsAcknowledgements

diabond

Documents

weibull statistics n

weibull mudulus distribution

university of genoa

abrasivity measurement

sawability measurement

p geometrical parameters

mixture properties

sda family diamond