Magatherm - EAF & LRF

8/17/2019 Magatherm - EAF & LRF

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Inner Diameter Nominal Continuous Rated ElectrodeModel of Furnace Capacity Capacity of Diameter

Shell (mm) (Ton) Transformer (KVA)

MT - 2S 2000 2 1500 6"

2000MT - 5S 2440 5 8"

2500

5000MT - 10S 3350 10 12"

6000

6000MT - 15S 3450 15 12"7500

9000MT - 20S 3650 20 14"

12000

15000MT - 25E 4000 25 18000 16"

21000

18000MT - 30E 4200 30 21000 16"

24000

21000 16"MT - 35E 4300 35 24000 16"

28000 18"

28000MT - 40E 4400 40 30000 18"

32000

32000MT - 45E 4600 45 18"

36000

35000MT - 50E 4800 50 20"

40000

42000MT - 60 E 5100 60 20"

48000

50000MT - 70E 5300 70 20"

60000

Electric Arc Furnace

An Electric Arc Furnace is defined in terms

of its shell diameter and transformer rating.

The shell diameter for a given furnace is

largely chosen as a function of tap weight

required and the steel making practise to be

adopted, the current trend is towards larger

shell diameter for a given weight. The choice

of tap weight is influenced by such factors

as dedication to continuous casting

machine, productivity requirement and

capital costs.

The transformer size determine the rate at which furnace can melt ferrous raw materials. The

following diagram gives the various inputs & outputs in an Electirc Arc Furnace.

Legend

1 Transformer

2 High-Voltage Switchgear

3 Hydraulic Unit

4 Pressure Vessel

5 Main Control Desk

6 Electric Control

7 Tilting Console

Typical Layout

Layout shows Arc Furnace equipped with Eccentric Bottom Tapping Device.

Inner Diameter ofModel A B C D

Furnace Shell (mm)

B

C

6

5

7

2

D

2

1

3

4

A

MT - 2S 2000 2880 4880 2000 5015

MT - 5S 2440 2880 4880 2000 5300

MT - 10S 3350 4318 6325 2007 7470

MT - 15S 3450 4318 6325 2007 8310

MT - 20S 3650 4344 6020 1676 9000

MT - 25E 4000 5327 7848 2521 10000

MT - 30E 4200 5327 7848 2521 10000

MT - 35E 4300 5327 7848 2521 10000

MT - 40E 4400 7848 10363 2515 10000

MT - 45E 4600 7848 10363 2515 10000

MT - 50E 4800 7348 9858 2510 10000

MT - 60 E 5100 7060 10310 3250 10000

MT - 70E 5300 6960 10110 3150 10000

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Arc Furnace Heat Balance

In an arc furnace energy can be supplied from a variety of sources as shown in the table

below. The energy distribution is highly dependent on local material and consumable costs

and is unique to the specific melt shop operation. A typical balance for Ultra High Power

Furnace and low or medium power is indicated here as under:

Inputs

Steel 55 - 60% 50 - 55%

Slag 8 - 10% 8 - 12%

Cooling Water 8 - 10% 5 - 6%

Miscellaneous 1 - 3% 17 - 30%

Off Gas 17 - 28% 7 - 10%

Total Outputs 100% 100%

Outputs

Energy Area UHP Furnace Low to MediumPower Furance

Electrical Energy 50 - 60% 75 - 85%

Burners 5 - 10%

Chemical Reactions 30 - 40% 15 - 25%

Total Inputs 100% 100%

Megatherm also provides “High-Speed Closed Loop Digital Electrode Regulation System”.The electrode regulator controls through hydraulic valves manual or automatic movementof electrode arms.

The system is implemented in dedicated standard PLC. The set up, tuning or monitoring isimplemented in PC.

To achieve, Impedance Control, a proportion of the arc voltage and a proportion of arccurrent flowing in the arc are compared thus giving measured impedance value. Measuredimpedance value is compared with the set value determined based on:

System Impedance

Furnace Impedance Transformer Impedance Primary Voltage

Tap Changer Position

Reactor Tap Position Current Setting

The resultant gives the error impedance signal. The electrical error signal is amplified and isfed to hydraulically operated proportional control valve to raise / lower the electrode arms

thus resulting in auto setting of electrode to operate at set impedance.

Electrode Regulation System

The heart of Electric Arc and Ladle Refining Furnace is the electrode regulator. The systemdetermines the efficiency of the furnace as it effects the consumption of power, electrodesand refractories.

There are two basic methods of moving the electrode arms, i.e thyristorised controlled Winchunit or Hydraulic regulation. Both are capable of operating efficiently. For bigger furnaceshydraulic regulation is preferred, whereas for smaller units either of the two is employed.

Hydraulic

ACor DCDrive

Winch

EBT Type

Spout Type

MotorGear Reducer

ValveControl

P.C.

R.C.D.

P.L.C. Unit

A-1/0

0/1-112 0/0-64 A/0-4 A/1-2

A-1/0

OLTC

Arc

ImpedanceMeasure

Unit

I V

HydraulicControlSystem




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Ladle Refining Furnace

Benefits

The increased oxidation (reduced oxygen

level) produces a very clean steel, good

desulphurization (by injection of Casi wire &

fluxes) and a decrease in non metallic

inclusions (removed by gentle stirring), result -

better quality of steel

The temperature and composition of melt can

be strictly controlled;

Better Homogenization – Temperature &

composition are equalized by stirring

The oxidized alloying elements in the slag can

be returned to the melt by reduction;

Large amount of alloying material can be added to produce high alloyed steel;

The melt can be held in ladle for long period of time and multiple ladles can be used to

pour a single large ingot;

The productivity of melting furnace is increased.

26

24

25

PLAN

55˚ SLEW

04

01

03

19

27

20

22

23

28

16

15

14

10

18

02

0517

11

09

13

12PLATFORM

ELEVATION

General Arrangement Drawing

Legend

01 Rocker Base

02 Column Side Rocker

03 Far Side Rocker

04 Bracket For Tilt Cylinder

05 Tilt Cylinder

09 Swivel Arrangement

10 Slew Platform

11 Substructure

12 Slew Roller Assembly

13 Column Guide Roller Assembly

14 Back Structure

15 Gantry Arm

16 Roof Lift Assembly

17 Column Cylinder Base Frame Assembly 18 Column Assembly

19 Shell -Bottom Part

20 Shell Top Part

22 Water Cool Panel Assembly

23 Water Cool Roof Assembly

24 Electrode Arm Assembly - Middle

25 Electrode Arm Assembly - Right Hand

26 Electrode Arm Assembly - Left Hand

27 Shell Lining Details

28 Maintenance Platform- Under Client Scope

Power Injection Lance

Argon

AdditionHopper

GraphiteElectrodes

Fume Extraction

Ladle Refining is a post steel making technological operation, performed in the ladle prior

to casting with the purpose of desulphurization, degassing, temperature & chemical

homogenization, deoxidation etc.

The normal LRF cycle lasts 40 –50 minutes depending upon the aim and final chemistry and desired temperature rise.




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8

7 3

5 4

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1

Ladle Refining Furnace Data Ladle Furnace with Cover Arragment

Ladle Dia. At Capacity of ElectrodeS.No. Capacity bath level (mm) Transformer Diameter

(Nominal)

1 10 950 2000 8"

2 12 1060 2500 8"

3 15 1160 3000 8"

4 18 1270 3600 10"

5 25 1500 5000 12"

6 30 1630 6000 12"

7 35 1761 7000 12"

8 40 1882 8000 14"

9 45 1996 9000 14"

10 50 2104 10000 16"

11 60 2306 12000 16"

12 70 2491 14000 16"

Legend

1 Ladle

2 Ladle Car

3 Cover

4 E lectrode

5 Electrode Holding Arm

6 Cover Lifting Arrangement

7 Water Cooled Cables

8 Busbar Arrangement (L. T. Side)

9 Current Transformer

10 Transformer

g _ y g

Documents

Magatherm - EAF & LRF