JSW Casting Equip

7/27/2019 JSW Casting Equip

1/23

A K KarandeSMS II , CCP Operation

1

Continuous casting equipment and its functions


2/23

A K KarandeSMS II , CCP Operation 2

LadleTurret

Ladle

Tundish Car

Mould

Top Zone

Bender

Segments

Straightener

Cut Off

Discharge

Tundish

Mould Oscillation

Dummy Bar

Continuous casting equipment


3/23


Ladle Turret

Funct ion: -

Supports the Ladle in Casting Position.

Usually Fitted with Lift/Lower Armsfor Ladle Covers

Allows Exchange of Full and Empty

Ladles

Allows Sequence Casting

Allows Emergency Rotation


4/23


Shroud manipulator

Funct ion:

Shrouding manipulator holds the refractory shroud

Protect the ladle stream and avoid the air ingress

Avoid re-oxidation of the steel

Perform submerged opening

Helps to detect the slag entry with slag detector fitted on arm


5/23


Tundish car

Funct ion:

Supports the Tundish.

Allows Transport of the Tundish from Pre-heat to Casting Position.

Allows Lift / Lower and Alignment of the Tundish SEN wrt mould.

Allows Exchange of Tundish during Sequence Casting.

Allows Emergency Removal of Tundish.

Tundish car


6/23


Tundish

Function: -

Provides a Stable Controlled Liquid Steel Feed to the Mould.

Ability to act as a reservoir during ladle changeover

Distribution of flow between strands

Provides a Uniform Steel Temperature to Each Strand.

Allows Floatation of Inclusion for Cleaner Steel.

Must Minimise Heat Loss from Liquid Steel During Casting. (usingtundish powder layer and tundish lid)

Weirs

Dams

Tundish PowderTundish Lid

Ladle Shroud

Tundish to Mould Shroud

minimum residence time = 7 - 8 minutes


7/23A K KarandeSMS II , CCP Operation7

Tundish Pre heaters

Funct ions: -

Moisture removal in tundish.

Avoid freezes of first incoming steel of the cast.

Avoid SEN choking during start of cast.

Maintain ideal super heat in tundish.

Avoid thermal shock to pouring refractory.

Ladle to tundish temperature drop minimized.

Smooth start of casting.


8/23A K KarandeSMS II , CCP Operation 8

Mould

It serves as:

A heat exchanger that handles a very high heat flux(>1 mw/m2).

A solidification device that builds up a thin solid shell.

A Die which gives its shape to the product without tearing the brittle shell.

A Chemical reactor with a huge through put which separate liquid steelfrom non-metallic.

The continuous caster mould performs several diverse functions in a

integration fashion



Heat transfer in mouldHEAT TRANSFER IN CONTINUOUS CASTING

Conduction through the solid shell

Heat transfer in the mould is

controlled by using casting flux:

Conduction through the copper

mouldConvection through the mould

cooling water

Solidification (Latent heat evolution

in the mushy zone)

Convection of liquid super heat to

the shell surface

The size and properties of the

interface between the shell and the

mould



Mould coolingHEAT TRANSFER IN CONTINUOUS CASTING

Mould water transfers heat from the solidifying shell

Mould cooling water flow, velocity and pressure is designed to

prevent both boiling and control the mould copper temperature.

Mould cooling should be as even as possible around the

circumference of the mould.



Break out prediction and Thermal mapping

Task

Solution Measured value of relevant processinformation

Evaluation of signals under

consideration of different process

situation

Data storage and management for

analysis of critical operating conditions

Prediction of stickers and reduction

of break-out rate



Mould oscillator

Mould oscillator is necessary to:

Minimize friction between mold plates & steel shell

Sticking of the solidifying shell

Avoid shell tearing

Avoid liquid steel break outs

Osci l lat ion Systems:-

Electro-mechanical (CC 1&2).

Hydraulic (CC 3)



Conventional Mould with Four Cam Oscillator

Fixed mould stroke

Sinusoidal wave formonly

Frequency varies directly

with casting speed

CC

1 & 2


14/23


Hydraulic Mould oscillator (CC-3)

Decrease of depth of oscillation mark

Increase of mould powder consumption

Decrease of frictional force between

solidified shell and mould-2

-1

0

1

2

Normalized Time

Stroke[mm

] SinusoidalNon-Sinusoidal

50%70%

Automatic mould water

connectionsBendersupport

Leaf spring

guiding

system

Mould fixation unit

Mould

centering

Weight

compensator

Mould table

Effect of non -sinu so idal osci l lation

Variable mould stroke

Sinusoidal and Non

sinusoidal wave forms

Variable frequency.


15/23


Mechanism of oscillation mark formation


16/23


Auto mould level control CC 1&2

TundishStopperRod

hydraulic-cylinder or

Electro mech.actuator

Scintilla.Counter

RadiationsourceMold

SMS

Automat ic funct ion ing of cast ing process

Constant and precise mold level

Elimination of slag entrapments

Accuracy +/- 5mm

Improvement of surface quality

Minimization of powder usage and

inclusions


17/23


Auto mould level control CC 3

Mould Level Controller

Control during all casting conditions

Auto start/resume cast

Accuracy 3 mm standard deviation

Backlash compensation

Clogging prevention (vibration,

knocking)

Actuator Electric actuator Electromagnetic

Measurement Stopper rod

Flow Control


18/23


Strand support

Slab caster Bloom caster


19/23


Function:

Plug the mould and enable start of casting.

Initiate withdrawal of the strand.

Controls withdrawal until the strand enters the drive rolls.

Types:

Top fed - used on high production casters - expensive option.

Bottom fed - used on low/medium production casters - cheaper option.

Restranding Times:

Top fed - 25 minutes minimum.

Bottom fed - 45 to 60 minutes.

Dummy bar and systems


20/23


Secondary Cooling Options:- Water only.

Limited turndown.

Used for less demanding steel grades.

Limited cooling capacityIncreased nozzle blocking tendency.

Air mist.

Increased turndown.

Used for all steel grades including critical grades.Increased cooling capacity (maximum K-factor > 30 [slab casting]).

Reduced nozzle blockage tendency.

Secondary cooling system


21/23


Speed tie contro l ( level 1 PLC)

Zone water flows vary directly with changes in casting speed.

Dynamic contro l (level 2 Compu ter)

Zone water flows vary with respect to the age of the strand

contained within each cooling zone.

Secondary cooling control system


22/23


Speed Tie Control

Zone Water Flow

Casting Speed

Time

Speed/WaterF

low

Time

Speed/WaterF

low

Casting Speed

Zone Water Flow

Effective Zone Speed

Dynamic Computer Control

Secondary cooling control system


23/23

A K KarandeSMS II CCP Operation 23

Time

Speed/Water

Flow

Casting Speed

Dynamic Control

Zone Water Flow

Speed Tie

Zone Water Flow

Under Cooling

Over Cooling

Comparison of cooling systems

JSW Casting Equip

Documents

Transcript of JSW Casting Equip