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7
CHEMICAL COMPOSITION AND DEOXIDATION PRACTICE
FOR HIGHER STRENGTH STEELS
enif dna dellik
ecitcarP noitadixoeD
grain treated
Chemical Composition %
(5) (7) (ladle samples)
C max.
0.18
0.16
Mn
0.90 - 1.60 (2)
0.90-1.60
Si max.
0.50
0.50
P max.
0.035
0.025
S max.
0.035
0.025
Al (acid soluble) min.
0.015 (3) (4)
0.015 (3) (4)
Nb
0.02 - 0.05 (4)total:
0.02-0.05(4) ) total:
V
0.05 - 0.10 (4) ) 0.12
0.05-0.10(4) ) 0.12
Ti max.
0.02 ) max.
0.02 ) max.
Cu max.
0.35
0.35
Cr max.
0.20
0.20
Ni max.
0.40
0,08
Mo max.
0.08
0.08
N max.
-
0.009
(0.012 if A1 is present)
Carbon Equivalent (6)
A32 D32 E32
F32
Grade (1)
A36 D36 E36
F36
A40 D40 E40
F40
Notes:
1.The letter “H” may be added either in front or behind the grade mark e.g. HA 32 or AH 32.
2. Up to a thickness of 12.5 mm the minimum manganese content may be reduced to 0.70%.
3.The total aluminium content may be determined instead of the acid soluble content.
In such cases the total aluminium content is to be not less than 0.020%.
4.The steel is to contain aluminium, niobium, vanadium or other suitable grain refining elements, either singly or in any combination. When used
singly the steel is to contain the specified minimum content of the grain refining element. When used in combination, the specified minimum
content of a fine graining element is not applicable.
5.When any grade of higher strength steel is supplied in the thermo-mechanically rolled condition variations in the specified chemical
composition may be allowed or required by the Classification Society.
6.When required, the carbon equivalent value is to be calculated from the ladle analysis using the following formula.
This formula is applicable only to steels which are basically of the carbon-manganese type and gives a general indication of the weldability of the steel.
7.Where additions of any other element have been made as part of the steelmaking practice, the content is to be indicated.
Ceq=C + + + (%)
Mn Cr + Mo +V Ni + Cu
6 5 15
Baglietto 2012_Layout 1 01/06/12 12.23 Pagina 7