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Clear Chill or definite
Chill Cast Iron Rolls
Manufacture of
Clear Chill Rolls utilise the unique property of iron and carbon
system whereby, controlling chemical composition and cooling rate,
the desired eutectic carbide is obtained on the surface layer (upto
a certain depth) and a graphite rich structure in the core with a
transition zone of mottled iron.
By controlled addition of various alloying elements, the surface
hardness and wear properties of chilled zone can be improved upto an
optimum limit beyond which the brittle nature of the white iron and
low tensile strength of mottled iron render the roll basically
unusable. Such rolls in general possess excellent wear resistance
and when alloyed with proper alloying elements have adequate
resistance to fracture, fire cracking and spalling.
NOMINAL CHEMICAL COMPOSITION & MECHANICAL PROPERTIES
%Chemical
Composition |
Mechanical Properties |
C |
Si |
Mn |
P |
S |
Cr |
Ni |
Mo |
Tensile Strength Kgf/mm2 |
Bending Strength Kgf/mm2 |
Hardness Sh0C |
Grade |
3.2
3.6 |
0.20
0.40 |
0.20
0.60 |
0.20
0.40 |
0.085
0.140 |
0.20
0.40 |
1.80
2.20 |
0.30
0.40 |
18-25
- |
30-40
- |
65-75
- |
01
- |
2.9
3.3 |
0.50
1.00 |
0.25
0.60 |
0.40
0.60 |
0.08
0.10 |
0.30
Max |
0.30
Max |
0.20
0.40 |
18-22
- |
30-40
- |
60-65
- |
07
- |
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MICRO STRUCTURE
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Non-Metallurgical Rolls (for
paper, rubber industries, etc)
Such rolls are produced out of special alloy
chilled cast iron with excellent surface finish, wear resistance and corrosion resistance.
Depending on the necessities of cooling or steam heating, core of the rolls can either be
smooth cast ( and thoroughly cleaned ) or machine bored as desired by our customers. The
chill depth is generally restricted in the 10-15 mm range. However, on special request,
higher chill depth can also be provided. Depending on the use, the barrel surface hardness
varies from 60/650 Shore C to 70/750 Shore C range. Full graphitisation of the inner layer
is ensured to impart maximum toughness. Rolls can be supplied in ground condition for
Cracker, Grinder Mills etc., for Rubber Industries and in duly cambered condition for
Rubber Refiner and Calender Machines as well as for Paper Calender Machines. All hollow
rolls are pressure tested hydraulically.
NOMINAL
CHEMICAL COMPOSITION & MECHANICAL PROPERTIES
C |
Si |
Mn |
P |
S |
Cr |
Ni |
Mo |
Tensile
Strength
Kgf/mm2 |
Bending
Strength
Kgf/mm2 |
Hardness Sh0C |
Grade |
3.40
3.75 |
0.20
0.60 |
0.20
0.60 |
0.40
0.55 |
0.085
0.140 |
0.50
Max |
1.00
Max |
0.30
Max |
-
- |
-
- |
60-75
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02
- |
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MICRO STRUCTURE
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Indefinite Chill or Grain Iron Rolls
The base composition of Indefinite Chilled Cast
Iron Rolls are controlled such that under actual moulding and casting conditions, unlike
clear chill, it does not give completely chilled graphite free zone distributed on the
surface, but contains a small amount of very finely divided graphite. The graphite
gradually increases both in size and amount from surface to center accompanied by decrease
in primary carbide content. The matrix is generally pearlitic throughout the cross-section.
Presence of high amount of alloying elements like Ni, Cr, Mo produces rolls with
restricted hardness drop along the cross-section. However, though cheaper, they are
gradually being replaced by better performing Spheroidal Graphite Rolls.
NOMINAL
CHEMICAL COMPOSITION & MECHANICAL PROPERTIES
% Chemical Composition |
Mechanical Properties |
C |
Si |
Mn |
P |
S |
Cr |
Ni |
Mo |
Tensile Strength Kgf/mm2 |
Bending Strength Kgf/mm2 |
Hardness Sh0C |
Grade |
2.90
3.50 |
0.90
1.40 |
0.50
1.10 |
0.30
Max |
0.10
Max |
0.90
1.40 |
1.50
2.40 |
0.25
0.40 |
20-28
- |
35-45
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45-75
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(03)
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MICRO STRUCTURE
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