RFCS Project RFSR-CT-2008-00040

Online Material Characterisation at Strip ProductionOnline Material Characterisation at Strip ProductionMathias Stolzenberg*, Rene Schmidt, Alvaro Casajus, Thomas Kebe, Magnus Falkenstrom,

Ane Martinez de Guerenu, Norbert Link, Henk Ploegaert, Frenk v. d. Berg

Consortium:Salzgitter Mannesmann Forschung (SZMF, Coordinator);

Arcelor Mittal Eisenhuettenstadt (AMEH);

Forschungs- und Qualitätszentrum Oderbrücke (FQZ);

ThyssenKrupp Steel AG (TKS);

Swerea KIMAB AB;

Centro de Estudios e Investigaciones Tecnicas de Gipuzkoa (CEIT);

VDEh Betriebsforschungsinstitut (BFI);

TATA SteelTechnology BV

TGS 9 09-11 June 2012 BFI, Düsseldorf, Germany

Duration: 01.07.2008 – 30.06.2011

Reporting Period: Final Report

Hysteresis featuresEddy current features

Remanence, coercitivity,

Speed of sound, damping, Reflections from phase borders

Elasticity, Scattering, absorption,

Measurable quantities by used methods

Direct signals

Physical properties

OMC Overview

Electromagnetic Ultrasonic

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Remanence, coercitivity, magnetic loss, differential permeability, impedance

Phase mixture, grain size, dislocation density, precipitation density, Phase composition ferrite / austenite

Elasticity, Scattering, absorption, Change in refractive index

Elastic properties, Hardness, Phase changes, Yield strength, Microstructure, Grain size,Phase changes, Defect detection

Material properties

OMC Overview

Project Structure

Ultrasonic Electromagnetic Destructive

Laser Ultrasonic

IMPOC Hacom Hysteresis Multi FrequencyImpedance Analyser (MFIA)

Online KIMAB, TKS, SZMF

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Online KIMAB, SZMF

TKS, FQZ, AMEH

SZMF

Samples KIMAB, SZMF

TKS, FQZ, AMEH

SZMF CEIT CEIT

Simulation TATA

Data Mining BFI SZMF CEIT TATA

Disturbance BFI

OBJECTIVES

Development of advanced online measurement techniques characterising the

structural parameters of the material to predict online the strip quality.

Development of measurement techniques and systems for production lines with

unfavourable conditions.

Online measurement data from the actual produced material for the adjustment of

process models to predict material quality with high resolution on the strip.

Evaluation algorithm relating the measured quantities to mechanical technological

OMC Overview

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Evaluation algorithm relating the measured quantities to mechanical technological

values.

Development of advanced methods like classification, neural networks or decision

trees to derive online interesting material quantities for quality control of production.

OMC Overview

Content

1 Basic Specifications

2 Application of Electromagnetic Methods

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2 Application of Electromagnetic Methods

3 Application of Ultrasonic Methods

4 Assessment of the Results and Discussion

1 Basic Specifications, Methods

Electromagnetic online Methods used in the project

Magnetizing Coils Measuring Coils

Running Strip

Magnetizing Coils Measuring Coils

Running Strip

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Ferromagnetic Strip

Idler RollersIdler Roller

Ferromagnetic Strip

Idler RollersIdler Roller

IMPOC (available system)Magnetic pulse, gradient of remanence

HACOM (available system)Sinusoidal magnetisation, harmonic analysis

1 Basic Specifications, Methods

Electromagnetic laboratory Methods used in the project

Hysteresis Curve for Working Distance 0 mm Hysteresis-like Curve, Working Distance: 0 mmB(T

)

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Single Sheet tester(available system)

Hysteresis Curve for Working Distance 0 mm

-8,000

-6,000

-4,000

-2,000

0,000

2,000

4,000

6,000

8,000

-1000 -800 -600 -400 -200 0 200 400 600 800 1000

H-Pulse in kA/m H

-Gra

die

nt

kA

/m²

gr-Hrns gr-Hrnm

gr-Hrn0

gr-Hrn09

gr-Hrnp9

Hc -Hc

I

II

III

IV

V

O

Multi Pulse Impoc (Development)Magnetic pulse cycles of different amplitude, gradient of remanence

H-Pulses (kA/m)

H-G

radie

nt (

kA/m

)

Hysteresis-like Curve, Working Distance: 0 mm

H-Pulses kA/m

Δµ

H (A/m)

1 Basic Specifications, Methods

Electromagnetic online methods developed in the project

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MFIA, Multi frequency impedance analyserchange of flux rate (eddy current)

1 Basic Specifications, Methods

Ultrasonic methods used in the project

Laser UltrasoundExcitation by Laser-pulse Detection by Interferometer

Ultrasound of different wave modes

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2 Application of Electromagnetic Methods, High Speed Impoc

High speed IMPOC installation at the CAL in Dortmund

Shape of magnetisation coils, amplitude andfrequency of pulses changed,

Results: No difference in shape of signals,good correlation to mechanical valuesfor IF and MA steel

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High speed IMPOC installation at the CGL2 in Eisenhüttenstadt

Shape of magnetisation coils, amplitude and frequency of pulses changed,

Direct comparison with two systems in the same line with different lift off

skin pass milltension leveller

(exit looper)

s1 s2

IMPOC orHighSpeedImpok

system 1 system 2

Results: A distance reduction (66 mm to 50 mm) increases the signal amplitude by app. 10%The change of IMPOC to HighSpeed IMPOC decreases the signal amplitude by 5 - 7%An adaptation of the system at a production line and/or the change of system type is possible

2 Application of Electromagnetic Methods, MFIA

MFIA Installation at TATA Steel Ijmuiden

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Ferrite fraction governs magnetic permeability:

2 Application of Electromagnetic Methods, MFIA

Developments:

• MFIA sensor + Instrumentation electronics

• Software and firmware to control the MFIA-sensor, to evaluate the results, to present basic measurements

MFIA output for a low C/Mn steel grade

Magnitude

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to present basic measurements

• Results from sensitivity studies on samples (in lab)

• An industrial housing to protect the sensor on the mill in a very hostile environment

• Initial result from a production HSM

Phase

speed influence of H360LA steel grade

10300

10400

10500

10600

IMP

OC

-valu

e [

A/m

2]

Data

Linear (Data)

2 Application of Electromagnetic Methods, Disturbing Influences

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y = -1,2887x + 10607

R2 = 0,8576

10000

10100

10200

10300

0 50 100 150 200 250 300 350 400

line speed [m/min]

IMP

OC

-valu

e [

A/m

2]

line speed dependence

-1,20

-1,00

-0,80

-0,60

-0,40

-0,20

0,00

IM

PO

C c

hange p

er

speed c

hange [A

min

/m3]

BH1

IF3

IF2

relative IMPOC change

-2,50%

-2,00%

-1,50%

-1,00%

-0,50%

0,00%

IF_1 IF_2 IF_3 BH_1 BH_2 BH_3 LA_1 LA_2 DP

rela

tiv c

hange o

f IM

PO

C p

er

100 m

/min

line s

peed c

hange [A

min

/ m

3]

900V

400V

2 Application of Electromagnetic Methods, Disturbing Influences

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0,2

- 0,

39

0,4

- 0,

59

0,6

- 0,

79

0,8

- 0,

99

1,0

- 1,

19

1,2

- 1,

39

1,4

- 1,

59

1,6

- 1,

79strip thickness [mm]

IM

PO

C c

hange p

er

speed c

hange [A

min

/m

-3,00%

-2,50%

Steel group

rela

tiv c

hange o

f IM

PO

C p

er

100 m

/min

line s

peed c

hange [A

min

/ m

The signal change with speed depends on Strip Thickness and Material

2 Application of Electromagnetic Methods, Modelling

Prediction of coarse grain from HACOM values at strip material

oven temperatures

HACOM Signals

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<- Strip length ->

Grain Structure

Multi Pulse IMPOC measurements, effects of skin pass treatment, different steel grades

2 Application of Electromagnetic Methods, Micro Structure Characterisation

2,0

4,0

6,0

8,0

10,0

H-G

rad

ien

t in

kA

/m²

10,0

20,0

30,0

40,0

50,0

60,0

Grad

ien

t k

A/m

²G

rad

ien

t (

kA/m

)

Gra

die

nt (

kA/m

)

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-10,0

-8,0

-6,0

-4,0

-2,0

0,0-800 -700 -600 -500 -400 -300 -200 -100 0 100 200 300 400 500 600 700 800

H-Pulse in kA/m

H-G

rad

ien

t in

kA

/m²

0,00%

0,50%

1,00%

1,50%

2,00%

-60,0

-50,0

-40,0

-30,0

-20,0

-10,0

0,0

-800 -700 -600 -500 -400 -300 -200 -100 0 100 200 300 400 500 600 700 800

H Impuls kA/m

Grad

ien

t k

A/m

²

0,00%

0,50%

1,00%

1,50%

DC56D+ZHCT340X+Z

H-Pulses (kA/m)H-Pulses (kA/m)

H-G

rad

ien

t (

H-G

rad

ien

t (

Skin pass level (%)Skin pass level (%)

Set 2- Cold strip galvannealed– HCT340X+Z – Annealing trials

-2 -1 0 1 2-1.5

-1

-0.5

0

0.5

1

1.5

B (

T)

UD1

UD2

UD3

UD4

UD 0º

Magnetic properties can be directly related to mechanical properties.

2 Application of Electromagnetic Methods, Micro Structure Characterisation

Step 1 and 2 Step 3 and 4

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290

300

310

320

330

340

350

1 2 3 4Annealing treatment

Yie

ld s

tren

gth,

Rp

0,2

(MP

a)

0º

45º

90º

UD

-2 -1 0 1 2H

t (kA/m)

700

750

800

850

900

950

1 2 3 4

Annealing treatment

Hc

(A/m

)

0º45º90ºUD

y = 4.2709x - 531.81

R2 = 0.9992

750

770

790

810

830

850

870

890

910

930

305 310 315 320 325 330 335 340

Yield Strength (Rp0.2)H

c (

A/m

)

DP600-90º

UD1/UD2 Banded microstructures

UD3/UD4 Equiaxed microstructures

Rp

0,2

(M

pa)

Annealing step Annealing step

Hc

(A/m

)

Hc

(A/m

)Rp0,2 (Mpa)

1200

1400

1600

1800

2000 51CrV4

DD13

HCT340X+Z (D)

DX56D+Z (UI)

Correlations between coercive field and mechanical yield strength for all the studied samples.

2 Application of Electromagnetic Methods, Mechanical and Magnetic Quantities

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0

200

400

600

800

1000

1200

0 200 400 600 800 1000 1200 1400

Hc

(A/m

)

Yield strength, Rp0.2 (MPa)

HCT340X+Z (D)

DX56D+Z (I)

HX380LAD+Z (EV)

HZ220YD+Z (IV)

SSAB

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

Br(T

)

51CrV4

DD13

HCT340X+Z (UD)

DX56D+Z (UI)

HCT340X+Z (D)

DX56D+Z (I)

HX380LAD+Z (EV)

HX220YD+Z (IV)

SSAB

No Correlations between magnetic hysteresis losses and remanent field

Hc,Br: different information about microstructure

2 Application of Electromagnetic Methods, Relations between Magnetic Quantities

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Correlation between magnetic hysteresis losses and coercive field

0.60 500 1000 1500 2000

Hc (A/m)

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 500 1000 1500 2000

Hyst

eres

is lo

ss (

J/m

3)

Hc (A/m)

51CrV4

DD13

HCT340X+Z (UD)

DX56D+Z (UI)

HCT340X+Z (D)

DX56D+Z (I)

HX380LAD+Z (EV)

HX220YD+Z (IV)

SSAB

Hc significantly affected by

carbon content, micro structural phase, grain size, dislocation density,

Br significantly affected by residual stresses, textureless by grain size, dislocation density

Hc,ML equivalent information about microstructure

3 Application of Ultrasonic Methods, Mechanical Models

LUS Ultrasound propagation

R

L

b1

G1G2

b2

R

L

b1 a1

G1G2

b2

R

G1

a1

a) b) c)

setups for velocity measurements.a) normal to surface, predefined thickness.b) different angles, velocity from comparison of different echo arrival times. c) A combination of a) and b)

iiE ii

LUS elastic constants

)(kkjj

ii

Young’s modulus Poisson’s ratio

SP

SP

VV

VV

2

2 SP

SPS

VV

VVV

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c) A combination of a) and b)

sfrequencielowf

sfrequenciehighf

fSpectrum

fSpectrumnattenuationormalised

_

_

)(

)(_

)(0 )()( LefUfU

fdK 1

AttenuationLUS-Parameter

d: grain diameter

v: exponent 2..4

4 in case of Rayleigh scattering

Setup of LUS measurements at the annealing simulator. The specimen is not visible due to the heat shielding

IF Steel

US-velocity at heated sample

3 Application of Ultrasonic Methods, Online Measurements

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not visible due to the heat shielding

Industrial installation of laser ultrasound at SSAB.Fibre coupled optical head in the format line.

5600

5700

5800

5900

6000

6100

14:38:24 14:45:36

Time [hh:mm:ss]

P-w

av

eve

loc

ity

[m/s

]

Start

14:24:00 14:31:12

Stop

14:52:48 15:00:00

US-velocity over coil length

3 Application of Ultrasonic Methods, Laboratory Samples, Characterisation

LUS Measurement at hot strip samples heat treatment 950°C 1: 0 min, 2: 1min, 3: 10min, 4: 60min, 5: 240min

51CrV4Sou

nd v

elo

city

m/s

6000

LU

S-P

ara

mete

r

0.8

Sound Velocity LUS-Parameter

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0.4

0.3DD13

DD13

0 1 2 3 4 5

Annealing time/ min

0 1 2 3 4 5

Annealing time /min

Sou

nd v

elo

city

m/s

5700

6000

5700

LU

S-P

ara

mete

r

0.1

0.5

0.2

1 2 3 4 5

Annealing time/ min

1 2 3 4 5

Annealing time/ min

LUS Spectra at hot strip samples, a-h increasing Martensite content

3 Application of Ultrasonic Methods, Laboratory Samples, Characterisation

HSLA1 DP2 Mart.2

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Mart.3HSLA2

DP1

HSLA2 DP3

Mart.1

4 Assessment of the online results

Online System Type of line Position Structural

Parameters

Application Main disturbing

influence

IMPOCEM, gradient of

remanence

Continuous lines,

HDG, CAL, PL,

low/high speed

Treatment part

(little speed

changes)

grain size,

dislocations

Homogeneity,

yield / tensile

strength

strip speed, tension

compensation

models available

Online methods examined

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MFIAEM, impedance

Hot strip, annealing Roll out table,

oven sections

Changes in

impedance

Determination

of ferritic phase

fraction

Curie point, lift off

LUSUltrasound speed

and frequency

content

Slabs, Hot strip,

Pickling line,

Annealing line,

After finishing

stands, Oven

sections

Elastic constants,

grain size,

attenuation (phase

dependent)

Homogeneity,

grain size in hot

sections,

(phase fraction)

High attenuation

above 1170K,

laser instabilities,

scale, air

turbulences, steam

4 Discussion of the results

• Magnetic losses, coercive field, permeability are main features for micro structure characterisation, textural information more from remanence

• All examined EM methods related to features of the hysteresis loop. Single sheet tester base method to determine relations of magnetic to micro structural parameters.

• MFIA (permaebility) shows development of the phase fraction, IMPOC and

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• MFIA (permaebility) shows development of the phase fraction, IMPOC and HACOM (magnetic losses, coercive field) are sensitiv for features of micro structure and mechanical parameters

• Sound speed, attenuation and US-spectra give access to micro structure.Laser-exited ultrasound applicable for temperature dependent measurements. Characteristic features in the spectra change with micro structure.

• Determination of material quantities at elevated and high temperatures. Calibration to material states is necessary,

Thank you for your

TATA Steel

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Thank you for your attention

Acknowledgements:This project was funded by the Research Fund for Coal and Steel (RFCS) of theEuropean Union

FQZ Oderbrücke