Post on 03-Jun-2018
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STEELS FOR HOT WORK APPLICATIONS
Torbjrn Spngberg, Olle Tnnberg, Bengt Klarenfjord, Uddeholm Tooling AB
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Torbjrn, Olle, Bengt, Rally 20082
Hot work Plastics
HPS
Cold work
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Torbjrn, Olle, Bengt, Rally 20083
Hot work applications
Die casting
Extrusion
Forging
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Torbjrn, Olle, Bengt, Rally 20084
Typical failures in hot work applicationsTypical failures in hot work applications
Heat checking ( thermal fatigue ) Gross cracking
Erosion / Hot wear Soldering
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Torbjrn, Olle, Bengt, Rally 20085
The demand on the die steel
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Torbjrn, Olle, Bengt, Rally 20086
Important die steel properties
Temper resistance
Hot yield strength
Creep strength
Thermal expansion
Heat conductivity
Ductility / Toughness
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Torbjrn, Olle, Bengt, Rally 20087
For a good performance you need both a
good die steel and a good heat treatment
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Torbjrn, Olle, Bengt, Rally 20088
Uddeholm hot work programme
ALVAR 14ALVARORVAR 2 MicrodizedVIDAR 1
ORVAR SUPREMEORVAR SUPERIORVIDAR SUPERIORQRO 90 SUPREMEHOTVAR
DIEVARUNIMAX
ALVAR 14ALVARORVAR 2 MicrodizedVIDAR 1ORVAR SUPREMEORVAR SUPERIORVIDAR SUPERIORQRO 90 SUPREMEHOTVAR
DIEVARUNIMAX
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Torbjrn, Olle, Bengt, Rally 20089
Chemical composition %Steel
C Si Mn Cr Ni Mo V
ALVAR 0,45 0,7 0,8 1,8 0,6 0,3 0,2
DIEVAR 0,35 0,2 0,5 5,0 2,3 0,6
ALVAR 14 0,55 0,3 0,7 1,1 1,7 0,5 0,1
VIDAR 1 0.38 1,0 0,4 5,0 1,3 0,4
VIDARSUPERIOR
0,36 0,3 0,3 5,0 1,3 0,5
ORVAR 2M 0,39 1,0 0,4 5,3 1,3 0,9
ORVARSUPREME 0,39 1,0 0,4 5,2 1,4 0,9
ORVARSUPERIOR
0,39 1,0 0,4 5,2 1,4 0,9
UNIMAX 0,50 0,2 0,5 5,0 2,3 0,5
QRO 90SUPREME
0,38 0,3 0,8 2,6 2,3 0,9
HOTVAR 0,55 1,0 0,8 2,6 2,3 0,9
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Torbjrn, Olle, Bengt, Rally 200810
Heat treatment
MachiningControl / Inspection
Electric arcfurnace
Vacuumdegasing
Ladle furnace Up-hill casting
Warehouse
Forging
ESR
Rolling
Homogenizingtreatment
Test certificate
PRODUCTION LINE
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Torbjrn, Olle, Bengt, Rally 200811
0
5
10
15
20
1988 1990 1992 1994 1996 1998 2000
Totalo
xygencontent(pp
m)andtoughness
,KV,
(J)
Remelting underprotected atmosphere
Toughness
Oxygen content
Process development
Special heat treatments
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Torbjrn, Olle, Bengt, Rally 200812
Microstructural influence on the ductility
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Test certificate
Chemical composition
Microcleanliness
Annealed microstructureand hardness
As quenched hardnessand grain sizeImpact toughness
Ultrasonic inspection
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Torbjrn, Olle, Bengt, Rally 200814
Effect of time on hardness at 600C
ORVAR SUPREME and ALVAR 14
0
5
10
15
20
25
30
35
40
45
2 5 15 65 100
HRC ORVAR
SUPREMEALVAR 14
h
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Effect of time on hardness at 550 C
20
25
30
35
40
45
50
55
60
HRC
1 10 100
hours
ORVAR SUPREME
QRO 90 SUPREMEHOTVAR
VIDAR SUPERIOR
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Effect of time on hardness at 600C
20
25
30
35
40
45
50
5560
HRC
1 10 100
hours
ORVAR SUPREMEQRO 90 SUPREME
HOTVAR
VIDAR SUPERIOR
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Yield strength at elevated temperatures
300
500
700
900
1100
MPa
550 575 600 650
Temperature C
HOTVAR, 58 HRC; QRO 90 SUPREME, 48 HRC; ORVAR
SUPREME, 53 HRC; VIDAR SUPERIOR, 45 HRC; DIEVAR, 47/48
HRC
ORVAR SUPREME QRO 90 SUPREME HOTVAR
VIDAR SUPERIOR DIEVAR
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Toughness at elevated temperatures
centre and short-tranverse direction
0
20
40
60
80
100
120
140
20 100 200 300 400 500
DIEVAR 45 HRC
ORVAR SUPREME
45 HRC
QRO 90 SUPREME
45 HRC
VIDAR SUPERIOR
45 HRC
Charpy V, J
C
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Toughness at elevated temperatures
centre and short-transverse direction
0
20
40
60
80
100
120
140
20 100 200 300 400 500
DIEVAR 38 HRC
DIEVAR 45 HRC
DIEVAR 47 HRC
Charpy V, J
C
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Testing of creep
resistance
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Creep testing at 550C and 500MPa
0
1
2
3
4
5
6
0 100 200 300 400 500 600 700 800 900 1000
Hours
Strain[%] H13
Hotvar
Dievar
QRO 90 Supreme 1030C
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Testing of heat checking
Air
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Heat checking test result
0
20
40
60
80
100
120
140
160
180
200
220
40 42 44 46 48 50 52
Hrdhet (HRC)
Maxsprickdjup(um)
DIEVAR
ORVAR
SUPREME
TA =1025C/30min
20-700C/air/800 cycles
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Min toughness values in short-transverse
direction at 44 46HRC
02
4
6
810
12
14
1618
20
Min toughness values
ORVARSUPREME
ORVARSUPERIOR
VIDARSUPERIOR
DIEVAR
Charpy V
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Rersistance to hot wear, plastic
deformation and thermal fatigue
HOTVAR
QRO 90 SUPREME
ORVAR SUPREMEVIDAR SUPERIOR
DIEVAR
ORVAR SUPERIORORVAR 2M
ALVAR 14/ALVAR
Product mapping
VIDAR 1
UNIMAX
Resistance to cracking
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ALVAR 14 / ALVAR
Application areas eg support tools in
extrusion and also forging dies
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ORVAR 2 MicrodizedVIDAR 1
Typical application area isAl-extrusion. Dies andcomponents.
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ORVAR SUPREME / SUPERIOR
Used in hot workapplications as anuniversal steel grade.Die casting and forging.
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VIDAR SUPERIOR
Used in die casting andforging.
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DIEVAR
Used in die casting andforging when the demands onhot strength andductility/toughness are high.
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DIEVARCustomer benefits
Fewer interruptions in production
Better surface quality of produced parts
Increased die life
Possibility for producing larger parts
Possibility for larger multi-cavity dies
Longer running periods betweenmaintenance work
Fewer interruptions in production
Better surface quality of produced parts
Increased die life
Possibility for producing larger parts Possibility for larger multi-cavity dies
Longer running periods betweenmaintenance work
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QRO 90 SUPREME
Used in small dies , insertsand cores.Eg brass die casting and
forging.Also for hard loadedextrusion dies and
components.
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HOTVAR
Used in applicationswhere hot wear or plasticdeformation are thedominating failuremechanisms. Eg smallforging dies.
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UNIMAX
Recommended in hot work applicationswhere high hardness in combination withhigh ductility and toughness are needed.
Eg Mg - die casting, forging dies and largeextrusion dies.
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The Cost Iceberg
Visible costs
Material / heat treatmentDie making
Hiden costs
MaintenanceInterruptions in productionLess availability in production lineLess after-treating of partsDelivery delays
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Trends in hot work and demands on tool steels
Larger dies needed with highestquality for long run production
Better wear resistance
Improved hardenability
Improved ductility andtoughness
Improved strength at elevatedtemperatures
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