The document discusses the design and material selection for hot rolling mill rolls used in steel plants, emphasizing the need for different chemical compositions and microstructures for various mill stands. It details the types of materials such as special alloy cast steel and nodular iron used in the manufacturing of rolls, along with their mechanical properties and heat treatment processes. Additionally, it provides specific chemical compositions and manufacturing ranges for various types of rolls like adamit and alloy steel rolls.

1. Department of Metallurgical and Materials Engineering, IIT Kharagpur
Course:- Material Design and Selection
A brief presentation on
Hot rolling mill rolls (steel plant)
Basic funda
“ The Chemical Composition and Microstructure
of the roll need to be changed for different stands,
from roughing till finishing stand ”
09MT3018
Piyush Verma
4th year UG, IIT Kharagpur

2.  occurs above the recrystallization temperature
 After the grains deform during processing, they recrystallize, which
maintains an equiaxed microstructure and prevents the metal from
work hardening.
 little directionality in their mechanical properties.
Grooves ( for manufacturing different Cross-Sections)
being made by CNC machines

3. Rolling mill Application Material of mill rolls
Roughing, intermediate mill Special alloy cast steel, Alloy
rolls nodular iron
Prefinishing and block mill HSS, Tungsten carbide
Straight bar and wire rod mill rolls
(Normally Rolls are Casted)
Finishing mill rolls for straight HiCr iron, Adamite
bar
2-Hi roughing mill work roll Special alloy cast steel, Tool
steel
4-Hi roughing mill work roll HiCr iron, ICDP
Plate mill
(Forged Rolls are used) ICDP*
Finishing mill work roll (Iron clad double pole)
*
ICDP- Its actually a electrical switch enclosed in an box of iron controlling Single-Phase
power in a Roll

4.  HI - ALLOYED ROLLS FOR TMT PLANTS
 Special steels alloyed with nickel, chromium & molybdenum.
 Used in breakdown, roughing & intermediate mills for finishing of heavy
sections.
 Statically cast and undergo a three stage high temperature heat treatment
comprising of annealing, normalizing & tempering rotation.
 Matrix structure is pearlitic or bainitic depending on the alloy content.
Chemical Composition
C% Ni% Cr% Mn%
3.00-3.30 1.50-1.80 0.40 max 0.20-0.35
3.20-3.50 1.70-2.60 0.40 max 0.20-0.35
Manufacturing Range
Diameter Upto 32 inches or 850 mm
Length Upto 80 inches or 2100 mm

5.  ADAMIT / ALLOY STEEL ROLLS
 Pearlite with some Cementite in the structure.
 Harder than other steel rolls.
 Inner hardness is about the same as that of the surface.
 Used in pre-finishing to polishing stands in structure mills, where wear resistance
is very important along with considerable amount of strength and toughness
Chemical Composition
C% Mn% Si% Ni% Mo% Cr%
1.70-1.80 0.70-0.90 0.50-0.70 1.10-1.60 0.20-0.40 1.20-1.50
Manufacturing Range
Diameter Upto 32 inches or 850 mm
Length Upto 80 inches or 2100 mm