Steels for Hot Work Applications

8/12/2019 Steels for Hot Work Applications

1/37

STEELS FOR HOT WORK APPLICATIONS

Torbjrn Spngberg, Olle Tnnberg, Bengt Klarenfjord, Uddeholm Tooling AB


2/37

Torbjrn, Olle, Bengt, Rally 20082

Hot work Plastics

HPS

Cold work


3/37


Hot work applications

Die casting

Extrusion

Forging


4/37


Typical failures in hot work applicationsTypical failures in hot work applications

Heat checking ( thermal fatigue ) Gross cracking

Erosion / Hot wear Soldering


5/37


The demand on the die steel


6/37


Important die steel properties

Temper resistance

Hot yield strength

Creep strength

Thermal expansion

Heat conductivity

Ductility / Toughness


7/37


For a good performance you need both a

good die steel and a good heat treatment


8/37


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


9/37


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


10/37


Heat treatment

MachiningControl / Inspection

Electric arcfurnace

Vacuumdegasing

Ladle furnace Up-hill casting

Warehouse

Forging

ESR

Rolling

Homogenizingtreatment

Test certificate

PRODUCTION LINE


11/37


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


12/37


Microstructural influence on the ductility


13/37


Test certificate

Chemical composition

Microcleanliness

Annealed microstructureand hardness

As quenched hardnessand grain sizeImpact toughness

Ultrasonic inspection


14/37


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


15/37


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


16/37


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


17/37


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


18/37


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


19/37


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


20/37


Testing of creep

resistance


21/37


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


22/37


Testing of heat checking

Air


23/37


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


24/37


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


25/37


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


26/37


ALVAR 14 / ALVAR

Application areas eg support tools in

extrusion and also forging dies


27/37


ORVAR 2 MicrodizedVIDAR 1

Typical application area isAl-extrusion. Dies andcomponents.


28/37


ORVAR SUPREME / SUPERIOR

Used in hot workapplications as anuniversal steel grade.Die casting and forging.


29/37


VIDAR SUPERIOR

Used in die casting andforging.


30/37


DIEVAR

Used in die casting andforging when the demands onhot strength andductility/toughness are high.


31/37


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


32/37


QRO 90 SUPREME

Used in small dies , insertsand cores.Eg brass die casting and

forging.Also for hard loadedextrusion dies and

components.


33/37


HOTVAR

Used in applicationswhere hot wear or plasticdeformation are thedominating failuremechanisms. Eg smallforging dies.


34/37


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.


35/37


The Cost Iceberg

Visible costs

Material / heat treatmentDie making

Hiden costs

MaintenanceInterruptions in productionLess availability in production lineLess after-treating of partsDelivery delays


36/37


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


37/37

TRUST IS SOMETHING YOU EARN, EVERY DAY.

Documents

Steels for Hot Work Applications