ELECTROSLAG REMELTING PROCESS

WHAT IS ESR?

Electroslag remelting is a secondary steel making process used for remelting and refining of Steels & Special Alloys which are used for special applications in aircraft, thermal and nuclear power plants ,defence hardware,etc.

A Molten PoolB Molten SlagC Water GuideD Water CoolingE Base plateF ClampedG ElectrodeH CrucibleI Ingot

DIFFERENT SECTION IN ESR

ESR PROCESS

SCHEMATIC OF ESR PROCESS :

INGOT

165 ton ESR ingot, 2,300 mm diameter x 5,000 mm long.

HOW IS IT DIFFERENT FROM THE OTHER REFINING PROCESS?

Homogeneous Solidification structure and;

complete chemical homogeneity in the

final structure.

HISTORY:

Process was 1st developed during II world war in USA.

Rediscovered in early 60’s due to extensive work on the process done in USSR.

In 1965 production of ESR Steel in Western World was about 10,000T per year.

In 1980 was about 200,000T per year.

PRESENT:

At, present it is estimated to about 400,000T per year in western countries

About 175 ESR is installed in USA. China has designed and installed largest

ESR in world capable of making ingots of weight upto 200 T.

In India production through ESR is about 2000 T per year.

To

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es

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

1965 1980 PRESENT

PRODUCTION THROUGH ESR IN WEST COUNTRIES

Year

PROCESS FLOW :CASTING OF STEEL INTO INGOT OR BLOOM

( ELECTRODE)

RE- MELTING OF INGOT OR BLOOM

PASSAGE OF LIQUID STEEL DROP BY DROP THROUGH SLAG

SOLIDIFICATION OF LIQUID STEEL AT THE BOTTOM OF MOULD.

PRODUCTION OF CLEAN STEEL

Metallurgy of the Electroslag Remelting Process

•Due to the superheated slag that is continuously in touch with the electrode tip, a liquid film of metal forms at the electrode tip.

Metallurgy of the Electroslag Remelting Process

As the developing droplets pass through the slag, the metal is cleaned of non-metallic impurities which are removed by chemical reaction with the slag or by physical flotation to the top of the molten pool.

The remaining inclusions in ESR are very small in size and evenly distributed in the remelted ingot.

CONTENTS OF SLAG:

Slags for ESR are usually based on:

calcium fluoride (CaF2), lime (CaO), alumina (Al2O3),. Magnesia (MgO) titania (TiO2), silica (SiO2) (depending on the alloy to be remelted.)

To perform its intended functions, the slag must have some well-defined properties, such as:

•Its melting point must be lower than that of the metal to be remelted ;

• It must be electrically efficient ;

• Its composition should be selected to ensure the desired chemical reactions;

•It must have suitable viscosity at remelting temperature.

SLAG CHARACTERISTICS:

FEATURES OF ESR: Ingot weights from 100 kg to 165 metric tons;

Ingot diameters from 170 mm to 2,300 mm depending on material being remelted;

Circular, square and rectangular ingot shapes are possible;

Alternating current as remelting energy with melting currents from 3 kA to 92 kA;

Systems for special processes such as remelting under pressure, protective gas or vacuum.

ADVANTAGES OF ESR:

Homogeneous, sound and directionally

solidified structure; High degree of cleanliness; Free of internal flaws (e.g. hydrogen

flakes); Free of macro-segregation; Smooth ingot surface resulting in a

high ingot yield.

ESR APPLICATION: Tool steels for milling cutters, mining, etc.; Die steels for the glass, plastics and automotive

industries; Ball-bearing steels; Steels for turbine and generator shafts; Superalloys for aerospace and power turbines; Nickel-base alloys for the chemical industry; Cold rolls.

SPECIFICATIONS:

Descripition of ESR

20'‘ 26“ 30“ 36“ 40“ 44“ 48“

Max. Ingot Weight.(T)

4 6 10 15 20 30 35

Max. Crucible Diameter (MM)

508 650 760 914 1016 1117 1219

Baseplate Dimension(MM)

825 1016 1016 1219 1372 1372 1473

Power supply rating (KAMPS)

15 20 25 30 35 40 40

DARK SIDE OF ESR

Cost Inefficient.S Not Eco-Friendly.

USAGE OF ESR PROCESS IN DEVELOPED COUNTRIES

Steel Melted %Usage

Tool and Die Steels 37.5

Stainless and Nickel base alloys

25.0

High Strength Constructional 25.0

Super alloys 12.5

Total 100

STEEL GRADES FOR DIFFERENT APPLICATION

Steel Melted Grades

Tool and Die Steels SAEA2,SAEH10,

SAEW110.etc

Stainless and Nickel base alloys

AMS5536,

ASME SB463,etc.

High Strength Constructional EN24,GOST4543,

OXH3M5a

Super alloys SAE330,SAE5666,

SAE553C.etc

APPLICATION IN INDIA

COMPANY LOCATION PRODUCTION

Firth steel Co Nagpur 500 T/ Yr

TISCO Jamshedpur Closed now

MIDHANI Ltd. Hyderabad 1200 T/ Yr

M/s Kalyani Steel Ltd

Pune Data not Available

HEC Ranchi 730T/Yr

SUPPLIERS OF ESR: Shanghai Metallurgy Import and Export Co., Ltd. [ Shanghai, China (Mainland) ]

Xian Abundance Electric Technology Co., Ltd. [ Shaanxi, China (Mainland) ].

ELMET-ROLL [Ukraine] NPO "Eloterm" [ Russian Federation ]

Wenzhou Dengtai Trade Co., Ltd. [China]

CONSARC Engg.Ltd. [Scotland ,UK]

ALD Vacuum Tech. [Hanov Germany]

FEEDBACK AWAITED:ON 17 TH AUGUST 2010 queries was mailed to:

•CONSARC Engg.Ltd. [Scotland ,UK]

•Inteco ESR Unit. [Austria]

For further information regarding :

Capital investment for making ingot of  250 to 400 Kgs  Varable cost of making steel through ESR route  Space required for installation of ESR  Can we use square bloom for melting  Can we get square ingot after ESR  What metallurgical advantages we expect from ESR route

THANK YOU !!!!!