What is Steel? What are the types of Steel? What is its application?
Steel is an Alloy of Iron and Carbon. Steel is divided as Low Carbon(Mild Steel) , Medium Carbon and High Carbon Steel based on Carbon content & Killed, Semi killed and Rimming
Steel based on deoxidation process. Application of Steel involves in various
Automobile, White Goods and Structural applications.
Steel is an Alloy of Iron and Carbon. Steel is divided as Low Carbon(Mild Steel) , Medium
Carbon and High Carbon Steel based on Carbon content & Killed, Semi killed and Rimming
Steel based on deoxidation process.Application of Steel involves in various
Automobile, White Goods and Structural applications.
What is the Raw material used for making Steel?
Pig Iron, Wrought Iron and secondary scrap.
What are Hot Rolled Coils?
Coils rolled from Slabs above Recrystallisation Temperature are called as Hot Rolled Coils.
What is CRCA? What are the applications of CRCA?
CRCA is Cold Rolled Close Annealed material. Applications of CRCA includes various Automobile, White Goods applications.
What components are being made by CRCA sheet in automobile sector?
Roller Bearing cages, Outer & Inner panels of Cars ( door, roof, bonnet, fender, Body side,
Floor, Dash, etc.) , Muffler & Silencer, Motorcycle & Scooter panels, Fuel tank of vehicles.
What is the process of making CRCA?
Hot Rolled coils are Pickled in hydrochloric acid, Cold Rolled in successive passes,
Electrolytically cleaned, Annealed in batch type furnaces in hydrogen atmosphere and Skin
passed with application of rust preventive oil to make CRCA in different grades and textures
( Bright & Matt )
What is the difference between Matt & Bright finish of the steel& what are the
applications of these?
Matt : Surface Roughness is 0.6 to 1.4microns. Bright : Surface Roughness is less than 0.5 microns.
Matt finish is used for Painting & drawing applications and Bright finish is for plating
What is cold rolling & for which steel grades this can be done?
Cold rolling is the mechanical working of the Steel below Recrystallisation
Temperature to achieve close thickness tolerances, better surface finish. Various grades
rolled in flat form are D, DD, EDD, IF grade, High Tensile strength.
What is the main difference between Hot Rolled Steel and Cold Rolled steel?
Cold Rolled steel will have closed thickness profile and good surface texture & flatness
compared with Hot Rolled Steel.Hot Rolled Steel is rolled above Recrystallisation
Temperature and Cold Rolled steel is of below Recrystallisation Temperature. Hot Rolled
coils are available above 1.60 mm to 10.00 mm thickness & Cold rolled sheets are available
up to 0.10 mm to 4.00 mm Worldwide.
What is Hot rolled slitting ? Why it is done?
Hot Rolled Slitting is removal of uneven edges & Saw edge of the Hot rolled Coil for
smoothening cold rolling operation.
What is Pickling? Why it is being done? Which Acid is used in Pickling process?
Pickling is the process of Acid cleaning of the sheet which removes Scale ( Fe2O3) from
the surface of the strip. These Oxide layers are to be essentially removed for smooth cold
rolling operation & better surface quality. Hydro Chloric Acid is generally used in Pickling
What is the advantage of 6HI Hitachi over other rolling mills?
Auto gauge control(AGC), Auto Shape control, X-Ray gauge, Universal crown & IMR
Shifting to have better thickness tolerances, good shape in comparison to other Rolling
What is Electrolytic Cleaning process& how it is different from other cleaning process
Electrolytic cleaning process is capable of removing micro fines of Iron & Dirt and other
unwanted foreign particles from cold rolled steel strip surface. This can not be obtained
from conventional cleaning processes.
What type of Alkali used in ECL?
Silicated Alkali with other additives like surfactants etc. is used to achieve required level of
What is Annealing? What are the types of Annealing? What are the benefits of a closed
Annealing is the process of Heat Treatment in which internal stresses of highly cold worked
material are relieved. Steps of annealing include stress releaving, recrystalaization and grain
growth. Batch type annealing and Continuous Annealing are two types of Annealing
What are the advantages of H2 annealing?
Inert atmosphere of H2 gas has good conductivity than N2 gas.This provides good surface
appearance of the strip and Consistency of property.
What is Kathabar process? & what are the benefits of it?
Kathabar process is the process of Cooling the Annealed coils to Room Temperature by
Circulation of controlled dehumidified air in closed atmosphere. This process prevents Rust
formation by humidity control in closed atmosphere.
What is Skinpass process? Why it is done over Steel? What is its advantage?
Skinpass is the process of removing Yield Point Elongation of Annealed sheet. This is done
for improving Surface finish & Flatness of the Strip. During this stage texture of steel is
defined with application of rust preventive oil and also shape control of the required gauge
by stress leveler.
What is Hot Dip Galvanizing? What are the applications of Galvanized sheets?
Hot dip galvanizing is the process of applying a zinc coating to Cold rolled steel strip by immersing the material in a bath consisting primarily of molten zinc. The simplicity of the
galvanizing process is a distinct advantage over other methods of providing corrosion protection.
Galvanizing forms a metallurgical bond between the zinc and the underlying steel , creating a
barrier that is part of the metal itself. In India Galvanized steel is generally used in Roofing,
Refrigerator door & body panels and manufacture of various parts Home appliances.
What is Roll grinding?
Material removal from rolls ( Used in cold rolling Mill ) with the help of grinding wheel is
What is EDT? What is its function?
EDT means Electrical discharge texturing machining. In this method material removal from
rolls by means of controlled electrical discharges between the tool electrode and the work
piece ie Rolls. Its function is to make the surface of the rolls from Bright to Matt Finish.
What is CRS & CTL? What is its function?
CRS is Cold Rolled Slitter & CTL is Cut to Length. CRS is being done for trimming the
sheet to the required Width in close tolerance. CTL is being done for cropping the sheet to
the required length.
What is Corrugation?
The process of forming or ribbing a flat sheet of material into a consistent, symmetrical profile
to increase that material's strength to weight ratio up to 30% over the conventional material.
The forming of sheet metal into a series of straight, parallel alternate ridges and grooves with
a rolling mill equipped with matched roller dies or a press brake equipped with specially
shaped punch and die.