andritz metals furnace technologies for latest …seaisi.org/file/8a-2 andritz furnace technologies...

ANDRITZ METALS

25-28 JUNE 2018

SEAISI Conference & Exhibition

FURNACE TECHNOLOGIES FOR

LATEST GENERATION OF AHSS

MARKET EVOLUTION

AUTOMOTIVE STEEL REQUIREMENTS

CHALLENGES FOR FURNACE DESIGN

CHAPTER OVERVIEW

SEAISI - JUNE 2018 2

AUTOMOTIVE INDUSTRY REQUIREMENTS

MARKET EVOLUTION IN HOT DIP GALVANIZING


Development of new grades of AHSS providing lighter and

stronger car body for:

• Improved vehicle crash resistance

• Improved fuel efficiency

• Reduced greenhouse gas emissions

• By 2020, CO2 emissions in Europe must be reduced to 95 grammes per km

• By 2025, fuel efficiency in USA must roughly double at 54.5 miles per gallon

AHSS : WEIGHT REDUCTION



Comparison of global CO2 regulations for new passenger

cars (source ICCT, june 2016)

CO2 emission regulation targets are <95 g/km in 2025

Placeholder for pictures;

align pictures to right guide

Total cost as a function of percent vehicle weight reduction.

(source ICCT Lightweighting Technology Development and

trends in U.S. passengers vehicles 2016)

Steel remains one the most cost effective

solutions to reduce BIW weight

AHSS : HIGHER STRENGHT & INCREASED FORMABILITY



Press hardened steels (PHS)

• Chemistry

• Coating

3rd generation of Advanced High Strength Steels

• Quench & Partitionning (Q&P)

• Carbone free bainite (CFB)

EVOLUTION OF NORTH AMERICAN MARKET

40% INCREASE OF AHSS BY 2025


"NEW" AUTOMOTIVE STEELS REQUIREMENTS


RTS Ac1

Ac3

CONVENTIONAL

ANNEALING CYCLE

For 3rd gen. AHSS,

austenitic annealing is

required

Optional slow cooling (~5-10°C/s)

to control ferrite fraction and

austenite Carbon enrichment

Flexible Cooling rate depending

on metallurgy and target product :

20°C/s to >150°C/s

Precise end of cooling temperature

for Q&P and CFB products

Controlled overaging

T° and time

High DFF exit T°

may be needed Rapid heating sections

working on partially

austenitic steels



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• FLEXIBILITY

1. Annealing temperature

flexibility

2. High soaking temperature

3. High speed cooling

4. Flexible overaging /

partitionning

5. Steel coatability

• FLEXIBILITY


flexibility




partitionning




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1. ANNEALING TEMPERATURE FLEXIBILITY

ANDRITZ SELAS DFF


• Ability to heat the strip up to

750°C in 2 passes

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2

3

4

DIRECT FIRED FURNACE (DFF)

SEAISI - JUNE 2018

Preheating :

Radiative waste gas

DN Burners :

Radiative flame

KB Burners :

Radiative flame

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• FLEXIBILITY


flexibility




partitionning



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• Radiant tubes commonly used in carbon steels production :

• Max tube temperature : ~1000°C

• Working tube temperature : ~930-950°C

• Risk of increasing tube temperature : lifetime decrease, creep

• Max strip temperature : ~850°C

• Other radiant tubes technologies :

• Fe-Cr-Al, SiC material tubes

• Max temperature : up to 1250°C

• Working temperature : ~1100°C

• Max Strip temperature : ~950°C

• Special care : exhaust gas temperature, environment (cladding,

refractories)

2. HIGH ANNEALING TEMPERATURE

RADIANT TUBES


• Electrical radiant tubes:

• I shape

• Limited power (40 kW/tube)

• Max tube temperature : 850°C

• Less performance than gas radiant tubes

• Wire or strip resistances:

• Ni-Cr Wire : 1250°C

• Molybdenum wire : 1400°C

• Special care : Surrounding equipment (cladding, refractory)

• Strip temperature up to 1100°C in Silicon steel furnace


ELECTRICAL RESISTANCES


• Used as pre-heating for increase capacity when no space available Ref.: TKS FBA8, Dortmund, Germany –Strip temperature ~160 to 300°C

• Used when end-heating temperature cannot be achieved with existing radiant tubes section: Flux Transverse induction technology

Ref.: AM Kessales CAL, Belgium – Strip temperature ~ 820 to 900°C • Used when end-cooling and overaging temperatures are below the zinc bath temperature (Al-killed, TRIP, Dual-

Phase with high austenite content steels) Ref.: VoestAlpine CGL#4, Austria – Before zinc bath – strip with up 40% austenite ~ 340 to 480°C Ref.: AM Gent CGL#3, Belgium – Inductors at different locations after cooling: strip with up 50% austenite ~ 150 to 480°C before zinc bath: strip with up 40% austenite ~ 350 to 480°C strip with up 10% austenite ~ 250 to 480°C Ref.: Tangshan CGL#6, China – Before zinc bath ~ 270 to 460°C Ref.: Yieh Phui CGL, China – Before zinc bath ~ 270 to 460°C Ref.: Tangshan CGL#6, China – Before zinc bath ~ 270 to 460°C Ref.: Baosteel CGL, China – Before zinc bath ~ 270 to 460°C Ref.: VoestAlpine CAL, Austria – Overaging ~ 270 to 350°C

Uniform, high yield rapid heating even on low thickness and high austenite content


INDUCTION HEATING


Induction coil outside the

atmosphere chamber is an

ANDRITZ SELAS patent

Un seal

• FLEXIBILITY


flexibility




partitionning



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ANDRITZ SELAS COOLING TECHNOLOGIES


2 to 10 °C/s

5 to 30 °C/s(*)

0 to 40 °C/s(*)

15 to 70 °C/s(*)

40 to 120 °C/s(*)

80 to 200 °C/s

Radiant cooling (air cooled tubes)

Slow jet cooling (HNx tubes)

Flexible Chamber (Cooling +

soaking)

Rapid Jet Coolers (HNx nozzles)

Differential Rapid Jet Cooling

highest cooling rates by

homogeneous temperature

distribution

Higher H2-concentration for

further increase of heat

transfer

Modular design for different

operating modes

(*) : 5% H2, 1,0 mm, 750°C->500°C

Differential Rapid

Jet Cooling : up to

100°C/s at 5% H2

ANDRITZ SELAS

PATENTED DRJC

Use of variable H2

content :

up to 170°C/s

Strip temperature

control accross

width.

HOMOGENEOUS STRIP

TEMPERATURE

3. HIGH SPEED COOLING


3. HIGH SPEED COOLING

DIFFERENTIAL RAPID JET COOLING (DRJC)


By optimized nozzle design Maximize heat exchange

By homogeneous temperature profile along strip with optimized

evacuation backflow Avoid flatness defects

By minimum strip distance (40 mm) with automatic control Increase heat transfer

By cooler modularization & control Horizontal & vertical flexibility

More than 20 installations in production Proven technology

DRJC DESIGN


Temperature

scanner

1 2 3 3 2

1 2 3 3 2

1 2 3 3 2

Strip

travel

• Adjustable flow rate over strip width and strip length

1

2

3

• Optimized nozzle profile

• Optimized return flow

• Adjustable nozzle to strip

distance during operation

DRJC DESIGN


CENTER CENTER

TEMPERATURE PROFILE CONTROL

DRJC DESIGN


CENTER CENTER

INNER INNER

INNER INNER


DRJC DESIGN


CENTER CENTER

INNER INNER

INNER INNER

OUTER OUTER

OUTER OUTER


DRJC DESIGN


Temperature

scanner

1 2 3 3 2

1 2 3 3 2

1 2 3 3 2

1

2

3

TEMPERATURE PROFILE CONTROL – SCANNER ACROSS STRIP WIDTH

• ± 5°C across strip width

DRJC DESIGN


Speed variation of all fans Close loop control with scanner (center)

Adjustment across the strip width (pressure) Close loop control with scanner

3 directions Modularity

Mod.1

Mod.2

Mod.3

Mod.4

TEMPERATURE PROFILE CONTROL – FAN & PRESSURE CONTROL

DRJC : EXAMPLES OF LINE RESULTS


Design Results

DRJC : EXAMPLES OF LINE RESULTS


At 5% H2

• LINE FLEXIBILITY


flexibility

2. High Soaking Temperature



partitionning : see

induction heating



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• LINE FLEXIBILITY


flexibility

2. High Soaking Temperature



partitionning



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5. STEEL COATABILITY


MnO MnO SiO2 MnSiO3

Fe Fe

Fe Fe

Zn Zn Zn Zn Zn

Preferential oxidation of Mn and Si - Non wettable oxides in Zn bath

Bare spots after coating

In H

eati

ng

Zo

ne

A

fte

r C

oati

ng

PREOXIDATION IN DFF ALLOWS COATING OF HIGH

Mn/Si STEELS


Fe

FeO

Fe

Fe

Zn

Fe

Operation Where

Heating AHSS

strip up to 750°C

Preheat

+ DFF RTH1

Ultra rapid

Oxidation

Last

Zone of

DFF

Preoxidation

chamber

Reduction of

FeO RTH + RTS

Defectless Zinc

Coating Zn bath

PREOXIDATION IN DFF


• Radiant cup burners:

Homogeneous O2 at the burners

• Multiple burners:

Homogeneous O2 across strip width

• Air/gas premix + Trimming:

Identical air/gas ratio for all burners +

Trimming for narrow strip

Comb.

Air

Natural

Gas

HOMOGENEOUS OXIDATION

PREOXIDATION IN DFF


• Accurate thickness of the oxide layer (200-300 nm) through:

• Accurate setting of air/gas ratio

• Accurate control of O2 rate in the waste gas

• A too thin layer will give coating problems

• A too thick layer could lead to roll pickup and incomplete reduction Permanent WG

analysis

ACCURATE OXIDATION

Customer Works Line Country Start-up Product Coating Pre- oxidation

ArcelorMittal Cleveland CGL USA 1991 Auto / AHSS GI/GA YES

Voestalpine Linz CGL #3 Austria 2003 Auto GI NO

Tata Steel Llanwern CGL UK 1991-

2004 Auto / AHSS GI/GA YES

Voestalpine Linz CGL #4 Austria 2007 Auto / AHSS GI YES

Voestalpine Linz CGL #5 Austria 2010 Auto / AHSS GI/GA YES

Baosteel Shanghai CGL China 2015 Auto / AHSS GI YES

ArcelorMittal Kessales CAL Belgium 2016 Auto / GEN3 EG - JVD YES

ArcelorMittal Gent CGL 3 Belgium 2018 Auto / GEN3 GI YES

ANDRITZ SELAS DFF REFERENCES

DEDICATED TO AHSS & 3RD GEN AHSS


THANK YOU !

andritz metals furnace technologies for latest …seaisi.org/file/8a-2 andritz furnace technologies...

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