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CARBON EQUIVALENT FOR HIGHER STRENGTH STEELS
UP TO 100MM IN THICKNESS PRODUCED BY TM.
Grade
Carbon Equivalent, max. (%)
(1)
t < 50
50 < t < 100
A32, D32, E32, F32
0.36
0.38
A36, D36, E36, F36
0.38
0.40
A40, D40, E40, F40
0.40
0.42
t: thickness (mm)
Notes:
1. It is a matter for the manufacturer and shipbuilder to mutually agree in individual cases as to whether they wish to specify a more stringent
carbon equivalent.
Mechanical Properties
For tensile test either the upper yield stress (ReH) or where ReH cannot be determined, the 0.2
percent proof stress (Rp 0.2) is to be determined and the material is considered to comply with the
requirements if either value meets or exceeds the specified minimum value for yield strength (Re).
The results obtained from tensile tests are to comply with the appropriate requirements
following tables.
Mechanical properties for normal strengths steelss
Grade
Yield
Strength
ReH
Tensile
Strength
Rm
(
)
Elongation
A5 (%)
(N/mm2)
min
(N/mm2)
A
B
D
E
235 400/500 (1)
22 (2)
Impact Test
t
≤
50
50 <t
≤
70
70 <t
≤
100
Long
(3)
Trans
(3)
Long
(3)
Trans
(3)
Long
(3)
Trans
(3)
Average Impact Energy (J) min
Test
Temp.
°C
+20
–
– 34(5) 24(5) 41(5) 27(5)
0 27 (4) 20 (4)
34
24
41
27
-20
27
20
34
24
41
27
-40
27
20
34
24
41
27
t: thickness (mm)
Notes:
1. For all thicknesses of Grade A sections the upper limit for the specified tensile strength range may be exceeded at the discretion of the
Classification Society.
2. For full thickness flat tensile test specimens with a width of 25 mm and a gauge length of 200mm the elongation is to comply with the
following minimum values :
3. See NOTE i)
4. Charpy V-notch impact tests are generally not required for Grade B steel with thickness of 25 mm or less.
5. Impact tests for Grade A over 50 mm thick are not required when the material is produced using fine grain practice and furnished
normalised.TM rolling may be accepted without impact testing at the discretion of the Society.
Thickness mm >5 > 10 > 15 > 20 > 25 > 30 > 40
≤
5
≤
10
≤
15
≤
20
≤
25
≤
30
≤
40
≤
50
Elongation % 14 16 17 18 19 20 21 22
(i) The carbon equivalent value is to be calculated from the ladle analysis using the following formula and to comply with the requirements of Table 3;
(ii) The following formula (cold cracking susceptibility) may be used for evaluating weldability instead of the carbon equivalent at the discretion
of the Classification Society;
In such cases the cold cracking susceptibility value required may be specified by the Classification Society.
For Thermo-Mechanical Rolling,
TM ( Thermo-Mechanical Controlled Processing,TMCP)
steels the following special requirements apply:
Ceq=
C
+ + + (%)
Mn Cr + Mo +V Ni + Cu
6 5 15
Ceq=
C
+ + + + + + + + 5
B
(%)
Si
Mn Cu Ni
Cr
Mo V
30 20 20 60 20 15 10
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