How It Works - Steel Production


steel dynamics is a leader in the mini

mill steelmaking industry with a focus

on value-added products with demanding

quality requirements and at the heart of

the mini mill process a more

environmentally friendly way of making

steel his scrap steel lots and lots of

scrap steel in fact about 75% of the

material SDI uses to make new prime

steel consists of scrap steel that is

often left to rust in junkyards or

litter the countryside SDI also owns

omni source a second largest scrap

recycling company in north america and

that's where our story begins at an omni

source facility in indianapolis omni

source collects and processes ferrous

scrap and non ferrous grout at more than

70 facilities around the country here at

one of omni sources five facilities in

indianapolis a gigantic shredder reduces

entire automobiles and other large

pieces of scrap into smaller sections

that will fit into the flat role

divisions electric arc furnaces after

the scrap is shredded giant magnets

separate the ferrous materials from the

non ferrous non ferrous scrap is

conveyed away for further sorting just

as in the mini mill steelmaking process

nothing goes to waste at a visual

inspection checkpoint employees remove

any non ferrous crap that's hung up with

the ferrous material

next the scrap is shipped to the flat

Lowell divisions mill at Butler in

northeast Indiana the mill campus

includes 15 miles of railroad track

capable of handling 700 rail cars at one

time for incoming scrap and outgoing

steel shipments the mill also receives

200 to 300 truckloads of scrap and other

raw materials every day it's a 24/7

operation that runs 365 days a year

330 tonnes scrap cranes and large front

loaders facilitate moving the scrap

around in and out of rail cars and

trucks and to the scrap Bay at the edge

of the milk shop where large magnets

lift up the scrap and place it into a

charging bucket scrap is loaded into the

charging bucket according to grade to

achieve the exact chemistry necessary

for our steel products each furnace heat

consists of 175 tons with at least 75%

of its ground and about 10 percent

liquid pig iron from iron dynamics a

division of SDI on the flat roll mill

campus SDI is also making iron rich

units with a pioneering process at

Mesabi nugget in Minnesota

both IDI and Mesabi use iron making

methods that are far more eco-friendly


additional blast furnaces mini males use

electric arc furnaces or IAF's which

required much less in the way of Natural

Resources versus traditional blast

furnaces for every tonne of Steel

produced by SDI we eliminate the need

for 2,500 pounds of iron or 1400 pounds

of coal and a hundred and twenty pounds

of limestone and we use significantly

less energy in the process the eaf

process also produces 67% less carbon

equivalent emissions in addition 95% of

our scrap comes from within 250 miles of

our plants the charging bucket is moved

to a position directly above one of the

mills to twin shale IAF's

the scrap is then released into the

furnace creating some real fireworks the

reason for the explosion is that a

portion about 40 tons of each heat of

molten steel is left in the furnace to

keep it hot for the next heat saving

time and money

once the scrap and pig-iron are loaded

the loof of the furnace is closed and

three large carbon electrodes are

lowered through an opening in the roof

then it's Showtime

and it's loud very very loud the rods

circulate our arc up to a hundred and

fifteen million watts of electricity to

melt the scrap at a temperature reaching

three thousand degrees Fahrenheit the

power is on for about 35 minutes to

complete the melting of each heat which

is a good reason why our monthly

electric bill is about seven to eight

million dollars once a heat is

completely melted the furnace is tipped

to pour off the slag a collection of

impurities that rises to the top of the

heat the molten steel is then tapped

through the bottom of the furnace and

into a ladle the steel then goes to the

ladle metallurgy furnace or lmf where a

variety of processes can be accomplished

including desulphurization and

deoxidation the temperature of the steel

can be adjusted with carbon electrodes

and the chemistry of the steel can be

changed by reducing some alloy elements

and the introduction of others from the

ladle metallurgy furnace the steel goes

to the thin slab caster x' on the caster

deck the turret rotates to exchange an

empty ladle with another ladle filled

with molten metal as it goes through the

casters the molten steel now about 2,800

degrees Fahrenheit is converted into a

continuous ribbon of steel approximately

60 millimeters thick and up to a hundred

and eighty feet

on these thin slabs can be rolled into

steel sheet much more quickly

efficiently and cost effectively than

the much thicker slabs produced a

traditional integrated steel mills

producing slabs up to 64 inches thick

the casters operate at maximum speed of

230 inches per minute and process 9,000

tons of steel in a 24 hour period going

through a 2,400 gallons per minute spray

of cooling water the slab is completely

solid in 24 seconds it has an exit

temperature of 2,100 degrees after being

sheared to length the slab goes through

one of two tunnel furnaces where the

steel is reheated to 2150 degrees before

going to the hot strip mill scale is

removed from the slab before it's rolled

with water jet spraying 4000 gallons per

minute at 3,500 pounds per square inch

slabs are reduced to meet customers

requirements on our seven stand hot

rolling mill seven 10,000 horsepower

motors drive the work rolls in the mill

stands and 4,000 tons of rolling force

per mill stand reduces the thickness of

the material to as little as one

or point zero for zero inches a new hot

band of Steel is automatically coiled on

average each coil weighs about 22 tons

or as much as 10 cars in the cold milk

complex coils are chemically cleaned

through the continuous pickle line

operating at 700 feet per minute the

pickle line has the capacity to process

1.6 million tons of steel annually

pickled and oiled coils can be sold as

finished products galvanized on the hot

rolled galvanizing line and sold his

finished products or further processed

through the cold reversing mill hot band

is uncoiled on the reversing cold mill

where the gauge will be further reduced

to his light as eleven thousand seven

inch coils that have gone through the

reversing mill are usually galvanized or

annealed on one of our two galvanizing

lines at Butler an employee removes the

dross or impurities from the surface of

a zinc pot holding as much as 180 tons

of molten metal SDI's galvanizing lines

offer a variety of value-added services

such as inline temper passing tension

leveling chemical treatment acrylic

coating and oiling anneal coils go

through the temper mill and are sold or

painted on our coil coating lines here

we are on the banks of the Ohio River in

southern Indiana

Jeffersonville produces hot dipped

galvanized galvalume acrylic coated


and acrylic coated galvanized steel as

wide as 61 inches in fact SDI is the

only company in North America to make

galvalume and widths wider than 50

inches before being introduced into the

main pot containing galvalume coating an

aluminum zinc ingot is

melted in a pre melt pot that flows into

the main pond to maintain a more

consistent temperature here a coil of

galvalume is checked for surface defects

Jeffersonville is also home to one of

our two state-of-the-art coil coating

lines operated by the flat low division

the coil coating lines at Jeffersonville

and at Butler give the division a

capacity to paint approximately 500,000

tons of steel each year SDI's flat row

division is the only steel mill

operation in the United States that

paints its own steel the eight story

accumulator unwinds the coil allowing

faster continuous coating some coils of

thinner gauge steel would measure as

long as five miles have completely

unwound the coil coating line has three

coders one for primer and two for the

top and bottom finish coating making

quick color changes possible these lines

have the most state of the art equipment

in the industry including vision

technology producing the highest quality

pre painted coils available in the world

weather coils are coated at butler or at

Jeffersonville the highest standards of

quality are maintained through

continuous monitoring with leading edge

technology and equipment and

well-trained eyes we recently installed

equipment that allows coils to be placed

on pallets coils placed on pallets are

easier to handle for our customers who

depend on forklifts to move materials in

their facilities coated coils are staged

for shipment to our customers in a broad

range of industries who use our steel in

a wide variety of applications scrap

produced during processing at

Jeffersonville is loaded for shipment

back to the butler milk

you guessed it the scrap will be melted

and used begin to make new steel it's a

full circle