Steel Melting Shop (SMS)

Rourkela Steel PlantSteel Melting Shop-II

Tarun|Haresh|Saketh|Sameer|Deepak|Gautham|Pranay

Why SMS?

It is the first Plant in Asia to adopt LD process of steel making.

It is the first steel plant in SAIL and the only one presently, where 100% of the slabs rolled are produced through the cost effective and quality centered continuous casting route.

It is the first steel Plant in India to adopt external desulphurization of hot metal by

calcium carbide injection process.

LD? Desulphurization?CaC2?

Casting?

Continuous casting?

Slabs

?

Hot metal?

Is there any mill integrating all these processes?

Quality centered?

STEEL MAKING PROCESS• The aim of SMS ,in the steel making process, is to mould the hard

metal into steel which is both strong and flexible.

• Higher the carbon content in steel the stronger it is.But,with a higher carbon content, there is lesser weldability.

• To tackle this problem, the steel finally obtained, should have a lesser carbon content(less than 2%) while also maintaining strength.

• The desired quality of steel can be obtained by three recognised process.

1)LD CONVERTER PROCESS.2)BESSEMER CONVERTER PROCESS.3)SECONDARY STEEL MAKING PROCESS.

LD PROCESS

• In SMS Steel is made by LD process.

• Hot metal from Blast Furnaces, Oxygen (from Tonnage Oxygen Plants) and Flux are the main input for steel making.

• Hot Metal and Scrap are charged in requisite quantity in converter. Oxygen is blown from the top and flux is added in the converter.

• During oxidation of hot metal, impurities in the hot metal get oxidised and are separated by mixing them with flux (lime).

• The impurities thus generated are known as Slag.

• Ladle additives like Ferro Alloys and Aluminium are added before or during steel produced in the converter is tapped into a preheated ladle to produce to the composition of required grades.

• The ladle containing liquid steel is homogenised by purging argon through it from bottom.

• The ARS/LHF liquid steel is converted to slabs in continuous casting machines in SMS-I & II.

Mixer and Desulphurization unit Two hot metal mixers store hot

metal, received from all the four blast furnaces.

1300 T capacity & avg. HM temp. is 1250°C to 1350 °C

homogenize the HM w.r.t. temperature & composition

Operating angle: 30 degrees

burners are used to maintain temp.

Except the sulphur reaction all the rest are oxidation processes and are favored under the oxidizing conditions of steel making. Generally the S reaction is dealt separately by means of external desulphurization.

Two Desulphurization units are provided for removing excess from the HM to the acceptable norms before the HM is charged into the converter.

The DS agents used are CaC2/ MgAl based compound are injected through top lance.

• CONVERTERS

• converters receive HM, scrap & Fe alloys with the help of cranes

• concentric vessels • lined with refractories

• Fe-Si and Si-Mn in the chip form and Al in the form of bars of 20 kg are added

• O2 from TOP is blown from top through a water-cooled lance at 11 atm pressure.

• tap to tap time (avg) is 45 min

PROCESS

Lining of the converter is inspected lime and scrap is added hot metal is charged measurement of bath height by a one metre steel

pipe in one of the nozzles oxygen is blown from top at a flow rate of 1000-

1200 Nm3/min for agitation of bath, indicated by luminous flame at converter mouth

converter is tilted to tap the liquid steel in to ladle

COMPOSITIONS

Ladle Preparation Bay•  Ladle bay is utilized for preparation of ladles

which is a vessel used to transport and pour out molten metals.

Ladle is steel shell, which is lined with refractory bricks.

After lining ,ladle is placed under burner for drying.

Preheated Ladle is placed horizontally on the ladle stand and inner surface is cleaned using compressed air.

TUNDISH PREPERATION BAY

• In metal casting, a tundish is a broad, open container with one or more holes in the bottom.

• It is used to feed molten metal into mould so as to avoid splashing and give a smoother flow.

• This bay is equipped to clean the used tundish and prepare this tundish for new sequence.

Ladle Heating Furnace (LHF)

Steel (1650 C) is tapped from the converter into the steel ladle by steel car and taken into a Ladle Heating Furnace (LHF) by overhead crane.

Steel is purged by means of argon from the bottom.

Final adjustment of temperature (arcing) and chemical analysis of steel.

Homogenizing the steel bath.

Argon Rinsing Station (ARS)Argon Rinsing Station (ARS) is also situated in the

same bay as LHF.

It has the facilities of LHF like final adjustment of temperature and chemical analysis of steel.

This is utilized during LHF shutdown or any other exigency condition.

Casters Provide steel on continuous basis.A water cooled copper mould, which gives the

required dimensions.Different zones of cooling.

Torch Cutting Machine(TCM)

Cut the slabs to the required length.

Done by oxy-acetylene gas flame.

Slab Yards Slabs produced are stored in two slab yards.

Two slab marking machines installed.

Slabs sent to Plate Mill and Hot Strip Mill.

SMS MATERIAL FLOW CHART

WASTE MANAGEMENT AND POLLUTION CONTROL-SMS

• CO gas produced in the process is collected in a gas holder. It is further used as fuel in different units.

• The dust which is collected, is used as slurry.

• Slag generated during the steel making process, is also recycled. It is dumped and cooled, then it is used by blast furnaces, and sometimes in SMS.