o44-surface tension and density of fe-mn alloys

Surface Tension and Density of FeSurface Tension and Density of Fe--MnMn AlloysAlloys

Minsoo Shin, Le Thu Hoai & Joonho Lee*

Dept. Mater. Sci. & Eng., Korea Univ.

September 15, 2010

ContentsContents

1. Motivation/Background

• High Mn Steels

• New Ferro-Alloy Process

• Thermodynamic & Thermophysical Properties

2. Experimental

• Experimental Setup

3. Results & Discussion

• Density of Fe

• Density of Fe-Mn Alloys

• Surface Tension of Fe-Mn Alloys

4. Concluding Remarks

5. Future Plans / Vision

60

80

100

U

nif

orm

Elo

ng

atio

n (

%)

IF

IF-HS

Why FeWhy Fe--MnMn Alloys?Alloys?

Limit of AHSSUTS(Mpa) x El(%) < 25,000 Mpa%

High Mn Steel

0 200 400 600 800 10000

20

40

Un

ifo

rm E

lon

gat

ion

(%

)

Tensile Strength (MPa)

MILD IS

IF-HS

BHMicroalloyed

CMnHSLA

DP

TRIP


60

80

100

U

nif

orm

Elo

ng

atio

n (

%)

IF

IF-HS400

600

800

1000

1200

Str

ess(

MP

a)

980TRIP 980TWIP980DPT.S. = 980 MPa

TWIP


0 200 400 600 800 10000

20

40

Un

ifo

rm E

lon

gat

ion

(%

)

Tensile Strength (MPa)

MILD IS

IF-HS

BHMicroalloyed

CMnHSLA

DP

TRIP0

200

Str

ess(

MP

a)

0 10 20 30 40 50 60 70Strain(%)



60000

80000

100000

T

.S. x

El.

(MP

a %

)

TWIP

MBIP

Medium MnTRIP(Batch)

Y.-K. Lee, Proceeding of the Workshop on High Mn Steels, 2009

*TRIP: Transformation Induced Plasticity

*TWIP: Twinning Induced Plasticity

*MBIP: Microband Induced Plasticity

*SBIP: Shear Band Induced Plasticity

0 5 10 15 20 25 30 350

20000

40000

T.S

. x E

l. (M

Pa

%)

Mn (wt%)

TWIP

SBIP

High Mn TRIP

TRIP(Batch)

Medium Mn TRIP (CAL)


New FerroNew Ferro--Alloy Manufacturing ProcessAlloy Manufacturing Process

Reduction Refining De-C


SEN(Submerged Entry Nozzle)

Tundish

Mould FluxLiquid Slag

MnAl Si

(MnO)(Al2O3) (SiO2)

Continuous Casting of High Continuous Casting of High MnMn AlloysAlloysMould

10

100

1000

10000

100000

Fe

Sn

Vap

or

Pre

ssu

re, P

a

Mn

Vapor Pressures of Liquid Iron and ManganeseVapor Pressures of Liquid Iron and Manganese

1600 1700 1800 1900 20000.01

0.1

1

10 Fe

Vap

or

Pre

ssu

re, P

a

Temperature, K1. Motivation/Background

Mn

High resolution CCD camera

Oxygen sensor furnace

Horizontal furnace

Sample temp. monitor

P.C. monitor

Experimental SetupExperimental Setup

Gas purificationsystem

Oxygen pressure monitor

furnace temp. monitorOxygen

sensor

M.F.C.

P.I.Dcontroller

Oxygen sensor furnace

pO2 = ~2x10-19 atm

2. Experimental

Effect of the Sample’s SymmetryEffect of the Sample’s Symmetry

7.2

7.4 Unsymetric Sample Symetric Sample

Den

sity

, g/c

m3

Unsymetric Sample

DX/D

Y=89%

Symetric Sample

DV/D

H=100%

DY

DX

1800 1820 1840 1860 1880

6.8

7.0

Den

sity

, g/c

m

Temperature, K2. Experimental

7.2

7.3

7.4

7.5 Jimbo et al. Vertman et al. Adachi et al. Morita et al. Frohberg et al. Dzhemilev et al. Present Work Present Work

Recommended by Iida & Guthrie

Den

sity

, g/c

m3

Density of Pure IronDensity of Pure Iron

1800 1810 1820 1830 1840 1850 1860 18706.8

6.9

7.0

7.1

Den

sity

, g/c

m

Temperature, K

ρ ρ ρ ρ (g/cm3) = 7.15 - 0.88 x 10-3 (T(K) – 1808.15)


Pure Fe

Fe-3wt%Mn

Fe-5wt%Mn

Density of FeDensity of Fe--MnMn AlloysAlloys

7.00

7.05

7.10

7.15

7.20D

ensi

ty, g

/cm

3

Fe-10wt%Mn

T = 1823K


1800 1810 1820 1830 1840 1850 18606.85

6.90

6.95

7.00

Den

sity

, g/c

m

Temperature, K

8.0

8.1

8.2cm

3 /mo

l

Density of FeDensity of Fe--MnMn AlloysAlloys

V = ΣΣΣΣ Xi Vi

VMn = 10.08

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.147.7

7.8

7.9

Vo

lum

e, c

m

XMn

VMn = 10.08

ρρρρMn = 5.45

ρρρρMn (literature)= 5.76 – 0.92x10-3 (T-1517.15) = 5.47


1800

1900

2000

Tem

per

atu

re /

K

IsoIso--Density Lines of FeDensity Lines of Fe--MnMn AlloysAlloys

0 20 40 60 80 1001500

1600

1700

Tem

per

atu

re /

K

wt%Mn3. Results & Discussion

1700

1800

1900

2000S

urf

ace

Ten

sio

n, m

N.m

-1

Surface Tension of FeSurface Tension of Fe--MnMn AlloysAlloys

Pure Fe

Fe-3wt%Mn

Fe-5wt%Mn

1800 1810 1820 1830 1840 1850 18601300

1400

1500

1600

Su

rfac

e T

ensi

on

, mN

.m

Temperature, K

Iida & Guthrie Recommended (Fe)

Present work: Fe Fe3Mn Fe5Mn Fe10Mn

Fe-10wt%Mn

T = 1823K


Calculation of Surface TensionCalculation of Surface Tension

β=

According to Yeum’s model

( ) ( )[ ]BulkExA

SurfaceExA

ABulkA

SurfaceA

AA GG

AX

X

A

RT ,,1)ln( −++= σσ ( ) ( )[ ]BulkEx

BSurfaceEx

BB

BulkB

SurfaceB

BB GG

AX

X

A

RT ,,1)ln( −++= σ

According to Butler’s model

The excess Gibbs energy was after Huang et al. (1989)

),(),( ,, Bulkj

BulkExi

MixSurfacej

SurfaceExi XTGXTG β=

Tanaka et al. showed that the surface tension of various liquid alloys was obtained by assuming that ββββMix is the same as ββββPure .

iLGPure

ii HA ,)1( ∆−= βσ 0.85 for liquid metal surface due to the

surface relaxation and surface atomic rearrangement (revised value from 0.83)


1400

1600

1800

2000

Su

rfac

e te

nsi

on

, mN

.m-1

Surface Tension of FeSurface Tension of Fe--MnMn AlloysAlloys

1500

1600

1700

1800

1900

2000

Su

rfac

e te

nsi

on

, mN

.m-11823K

0 20 40 60 80 100

1000

1200

1400

Su

rfac

e te

nsi

on

, mN

.m-1

Theoretical calculation Recommended by Iida and Guthrie Experimental data

wt%Mn

0 2 4 6 8 10 121500 S

urf

ace

ten

sio

n, m

N.m

-1

wt%Mn


IsoIso--Surface Tension Lines of FeSurface Tension Lines of Fe--MnMn AlloysAlloys

1800

1900

2000T

empe

ratu

re /

K

L

0 20 40 60 80 1001500

1600

1700

Tem

pera

ture

/ K

wt% Mn 3. Results & Discussion

1. Density and surface tension of Fe-Mn alloys (wt%Mn = 0, 3, 5, 10) were investigated using the sessile drop method.

2. Density of pure Fe was re-estimated to beρρρρ (g/cm3) = 7.15 - 0.88 x 10-3 (T(K) – 1808.15)

3. Extrapolated value of the molar volume of pure Mn from the composition dependence of the molar volume of Fe-Mn alloys

Concluding RemarksConcluding Remarks

composition dependence of the molar volume of Fe-Mn alloys showed reasonable accordance with the literature value.

4. Based on the present experimental results, Iso-density lines of Fe-Mn alloy could be successfully derived.

5. The surface tension of Fe-Mn alloys showed reasonable accordance with the calculated values based on Butler’s equation.

Future Plan & VisionFuture Plan & Vision

1. Density and surface tension measurements of Fe-Mn-Si-C alloys will be examined.

2. Electrostatic levitation technique is currently examined.

3. Surface tension and density modeling of Ferro alloys containing interstitial elements (C, N, etc.) is challengeable.

4. Experimental and theoretical results obtained from this research project will contribute to establish a new refining facility and corresponding process for high purity Ferro Manganese alloys.

5. Mass production of high manganese eco-steels will help to reduce CO2 emission in many applications.

Concluding RemarksConcluding Remarks

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o44-surface tension and density of fe-mn alloys

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