Nodular cast iron
GNF, GNP, GNST, GNA, GNC, GNL, CNF, CNP, CNA
Applications
GNF (CNF) rolls are used in place of cast steel rolls
wherever high resistance to wear and thermal stresses is
needed. This grade is particularly suitable for the use on
roughing stands.
The main application of the GNP, GNST and GNA rolls
is for the section rolling mill process. According to the
metallurgical characteristics and hardness, they can be
used on roughing, intermediate and finishing stands for
small, medium and heavy section mills.
The rolls of the GNC series are generally employed as
work rolls in four-high and three-high stands of plate,
roughing and finishing mills and as back-up rolls for
skin-pass and temper mills. GNL rolls are particularly
suitable for use in plate mills and for roughing stands of
large strip mills. CNP series are used as pre-finishing
and finishing rolls for small and medium section mills,
roughing, intermediate, and pre-finishing rolls for wire
mills, intermediate and pre-finishing rolls for small and
medium rod mills and pre-finishing rolls for small and
medium bar mills.
CNA series are used as intermediate and pre-finishing
rolls for wire mills, pre-finishing and finishing rolls for
small and medium section mills, and as finishing rolls for
reinforced rod mills.
Nodular cast iron
GNF, GNP, GNST, GNA, GNC, GNL, CNF, CNP, CNA
Chemical analysis
TYPE
C
Si
Mn
Cr
Ni
Mo
GNF, CNF
3.00÷3.50
1.40÷2.20
0.40÷0.80
Max 0.30
1.40÷3.20
0.20÷0.80
GNP, CNP
3.00÷3.50
1.40÷2.20
0.40÷0.80
< 0.70
1.40÷3.20
0.20÷0.50
GNST
3.00÷3.50
1.40÷1.80
0.40÷0.80
0.60÷1.10
1.40÷3.20
0.20÷0.50
GNA, CNA
3.00÷3.50
1.40÷2.20
0.40÷0.80
< 0.70
2.50÷4.00
0.70÷1.20
GNL
3.00÷3.50
1.60÷2.20
0.40÷0.80
0.80÷1.20
3.00÷3.60
0.40÷0.60
GNC
3.00÷3.50
1.90÷2.40
0.40÷0.80
0.80÷1.40
4.00÷4.60
0.40÷0.80
Mechanical properties
TYPE
Hardness
(ShC)
Tensile
strength
(MPa)
Bending
strength
(MPa)
Impact
resistance
(J/m2 * 104)
GNF, CNF
35÷55
~ 750
~ 1500
~ 3.5
GNP, CNP
45÷70
400÷500
700÷800
~ 2.5
GNST
55÷75
~ 450
~ 730
~ 2.3
GNA, CNA
50÷75
400÷600
~ 900
~ 2.6
GNL
55÷65
~ 400
~ 650
~ 2.3
GNC
65÷80
~ 400
~ 700
~ 2.5
Modulus
of elasticity
(GPa)
~ 180
Microstructure of roll materials
GNF (100x)
GNP (100x)
GNST (100x)
GNA (100x)
GNL (100x)
GNC (100x)
Characteristics
GNF (CNF) rolls are nodular cast iron characterized by the almost complete absence of carbides and a ferritic matrix. GNP
(CNP) and GNST rolls have nodular graphite and carbides surrounded by pearlitic matrix. The GNST rolls have a larger quantity
of carbides than the GNP rolls, because of the higher chromium content and lower silicon content. GNA (CNA) series are
characterized by nodular graphite and carbides in a mostly bainitic matrix, due to high contents of nickel and molybdenum.
GNC rolls are the compound version of this group of material. GNL rolls belong to the nodular cast iron range. They have a
pearlitic matrix with dispersed carbides.