LR DH32 is a higher-strength structural steel plate certified by Lloyd's Register (LR) for shipbuilding and marine applications. The "D" grade signifies it is impact tested at -20°C . It has a minimum yield strength of 315 MPa (46 ksi) and tensile strength ranging from 440 to 590 MPa (64-83 ksi), with minimum elongation of 22% . The chemical composition is strictly controlled with carbon ≤0.18% and manganese 0.90-1.60% . It is widely used for hull structures, offshore platforms, and marine engineering components.
LR DH36 is also a higher-strength structural steel plate certified by LR, with the same impact test temperature of -20°C . The "36" denotes a minimum yield strength of 355 MPa and tensile strength ranging from 490 to 630 MPa, with minimum elongation of 21% . The chemical composition is similar to DH32 with carbon ≤0.18% and manganese 0.90-1.60%, though DH36 may contain microalloying elements like Nb and V to achieve its higher strength . This grade is designed for more demanding load-bearing applications in shipbuilding, including hull shells, longitudinal stiffeners, and primary structures.
Both LR DH32 and LR DH36 are LR-certified higher-strength marine steels with impact toughness tested at -20°C, ensuring reliable performance in cold marine environments . Their primary difference lies in strength level: DH32 offers a minimum yield strength of 315 MPa with tensile strength of 440-590 MPa, suitable for general high-strength hull construction and secondary structures, while DH36 provides a higher minimum yield strength of 355 MPa with tensile strength reaching 490-630 MPa, designed for more demanding load-bearing applications requiring superior strength . Both grades feature controlled chemical composition and maintain good weldability for critical marine service.
Chemical Composition
|
LR DH32 high Strength Chemical Composition |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
Al |
N |
|
|
LR DH32 |
0.18 |
0.05 |
0.9-1.6 |
0.035 |
0.035 |
0.015 |
|
|
Nb |
V |
Ti |
Cu |
Cr |
Ni |
Mo |
|
|
0.02-0.05 |
0.03-0.10 |
0.02 |
0.35 |
0.20 |
0.40 |
0.08 |
|
|
LR DH36 high Strength Chemical Composition |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
Al |
N |
|
|
LR DH36 |
0.18 |
0.05 |
0.9-1.6 |
0.035 |
0.035 |
0.015 |
|
|
Nb |
V |
Ti |
Cu |
Cr |
Ni |
Mo |
|
|
0.02-0.05 |
0.03-0.10 |
0.02 |
0.35 |
0.20 |
0.40 |
0.08 |
|
Mechanical Property
|
LR DH32 high strength property |
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|
Grade |
|
Mechanical Property |
Charpy V Impact Test |
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|
Thickness |
Yield |
Tensile |
Elongation |
Degree |
Energy 1 |
Energy 2 |
|
|
LR DH32 |
mm |
Min Mpa |
Mpa |
Min % |
-20 |
J |
J |
|
t≤50 |
315 |
440-590 |
22% |
20 |
31 |
||
|
50<t≤70 |
315 |
440-590 |
22% |
26 |
38 |
||
|
70<t≤100 |
315 |
440-590 |
22% |
31 |
46 |
||
|
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal |
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|
LR DH36 high strength property |
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|
Grade |
|
Mechanical Property |
Charpy V Impact Test |
||||
|
Thickness |
Yield |
Tensile |
Elongation |
Degree |
Energy 1 |
Energy 2 |
|
|
LR DH36 |
mm |
Min Mpa |
Mpa |
Min % |
-20 |
J |
J |
|
t≤50 |
355 |
490-630 |
21% |
24 |
34 |
||
|
50<t≤70 |
355 |
490-630 |
21% |
27 |
41 |
||
|
70<t≤100 |
355 |
490-630 |
21% |
34 |
50 |
||
|
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal |
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