ABS EQ70 and DQ70 are both high-strength, quenched and tempered shipbuilding steels from the SSAB American Bureau of Shipping (ABS) standard, offering excellent yield strength (around 690 MPa or 100 ksi) for marine structures like ship hulls and offshore platforms, with the primary difference being their specific Charpy V-notch impact test temperature requirements (e.g., DQ being for colder conditions than EQ) indicating varying toughness levels, making them suited for different operational environments. Both are quenched & tempered (Q&T) for strength, but the letters (A, D, E) denote the toughness criteria for specific service temperatures.
Chemical Composition
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ABS EQ70 Extra high Strength Chemical Composition in Tempering and Quenching |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
N |
|
|
ABS EQ70 |
0.20 |
0.55 |
1.7 |
0.030 |
0.030 |
0.02 |
|
ABS DQ70 Extra high Strength Chemical Composition in Tempering and Quenching |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
N |
|
|
ABS DQ70 |
0.20 |
0.55 |
1.7 |
0.030 |
0.030 |
0.02 |
Mechanical Property
|
ABS EQ70 Extra high strength property in tempering and quenching |
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|
Grade |
Mechanical Property |
Charpy V Impact Test |
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|
Yield |
Tensile |
Elongation |
Degree |
Energy 1 |
Energy 2 |
|
|
Min Mpa |
Mpa |
Min % |
-40 |
J |
J |
|
|
ABS EQ70 |
690 |
770-940 |
14 |
41 |
62 |
|
|
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal |
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|
ABS DQ70 Extra high strength property in tempering and quenching |
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|
Grade |
Mechanical Property |
Charpy V Impact Test |
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|
Yield |
Tensile |
Elongation |
Degree |
Energy 1 |
Energy 2 |
|
|
Min Mpa |
Mpa |
Min % |
-20 |
J |
J |
|
|
ABS DQ70 |
690 |
770-940 |
14 |
41 |
62 |
|
|
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal |
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Key Similarities:
Type: High-strength, Quenched & Tempered (Q&T) structural steel.
Strength: Minimum yield strength of 690 MPa (100 ksi).
Application: Used in shipbuilding, offshore platforms, and marine structures.
Process: Require quenching and tempering for enhanced properties.
Key Difference:
Toughness (Impact Testing): The letters A, D, and E (and Q for DQ/EQ) signify the specific low-temperature Charpy V-notch impact toughness required, with 'Q' often denoting higher performance, indicating suitability for colder waters or more extreme conditions, though the exact temperature varies. but the core difference is toughness for temperature.
