ABS DQ51 (also written AB/DQ51, ABS Grade DQ51, DQ51 steel plate) is an extra-high-strength steel plate to ABS Rules Part 2, Chapter 1, Section 8 (2018). The number 51 is the yield category (500 MPa minimum, tensile 610-770 MPa) and the prefix DQ sets the Charpy test temperature of -20°C. Grades of this family are supplied quenched and tempered (QT) or thermo-mechanically rolled (TM). It corresponds to grade D500 in IACS UR W16; ASTM A131 does not cover this strength level.

Related grades: ABS AQ51 steel plate ABS EQ51 steel plate ABS FQ51 steel plate ABS DQ47 steel plate.

Gangsteel is specialized in supplying ABS Extra high strength steel plate in ABS Grade DQ51. For more information of Grade DQ51 steel plate, please check them in following:

 

 

AB/DQ51  Extra high Strength Chemical Composition in Tempering and Quenching

AB/DQ51

ABS DQ51 chemical composition, % – heat (ladle) analysis and product (check) analysis
Element Heat analysis (max/min) Product analysis
C ≤ 0.18 ≤ 0.22
Mn ≤ 1.70 ≤ 1.84
Si ≤ 0.80 ≤ 0.86
P ≤ 0.025 ≤ 0.035
S ≤ 0.015 ≤ 0.025
Al (total) ≥ 0.018 — (no tolerance in ASTM A6 Table A; product value not given)
Nb ≤ 0.06 ≤ 0.07
V ≤ 0.12 ≤ 0.14
Ti ≤ 0.05 ≤ 0.06
Ni ≤ 3.50 ≤ 3.57
Cu ≤ 0.50 ≤ 0.53
Cr ≤ 2.00 ≤ 2.06
Mo ≤ 0.70 ≤ 0.74
N ≤ 0.015 ≤ 0.020
Ca ≤ 0.005 — (no tolerance in ASTM A6 Table A; product value not given)
B ≤ 0.005 product analysis not applicable (A6 Table A)

ABS 2022: limits shown are for the quenched and tempered (QT) condition; N/NR/CR and TM supply have different limits in Table 4A. Al/N ≥ 2:1 (not required when other N-binding elements are used); higher C or N may be agreed with ABS; Ni content agreed at qualification; final chemistry must also meet the mill's ABS-approved specification. Product analysis = heat limit ± ASTM A6/A6M Table A permitted variation (band chosen by the specified maximum/upper limit); applies only when product (check) analysis is required; for a range, results may not vary both above and below it. Per ABS Rules for Materials and Welding Part 2 (2022); product analysis tolerances per ABS 2-1-2/5.3 (“chemical tolerances of ASTM A6”) and ASTM A6/A6M 7.2, Table A (also invoked by ASTM A131). Heat limits: ABS 2-1-8/4 Table 4A (2022), QT column.

 

Crack Sensitivity:  Pcm = (C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B)%
Carbon Equivalent:  Ceq = 【C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15】%

 

 

 

AB/DQ51 Extra high strength property in tempering and quenching

AB/DQ51

ABS DQ51 mechanical properties
Grade Yield ReH min (MPa) Tensile Rm (MPa) Elongation A5 min (%) Charpy test temp (°C) Impact energy avg min, longitudinal (J) Impact energy avg min, transverse (J)
AB/DQ51 500 610-770 16 -20 50 33

Source: ABS Rules Pt 2, 2-1-8, Table 5A. Either longitudinal or transverse specimens per the order.

Boiler steel plates| Alloy steel plates| High strength plate| Carbon steel plate

 

 

 

 

 

Equivalent steel grade of AB/DQ51

DNV

GL

LR

BV

CCS

NK

KR

RINA

NV D500

GL-D500

LR/DH50

BV/D500

CCS/D500

K D51

R D51

RI/D500

 

 

 

 

If you need more stock steel plates in shipbuilding steel plate, please click warehouse sizes.

 

 Related steel grades: AB/DQ47, AB/DQ43, AB/DH40, AB/DH32

 

 

 

ABS Steel Plate Grade Supplier

General Strength

AB/A

AB/B

AB/D

AB/E

High Strength

AB/AH32

AB/DH32

AB/EH32

AB/FH32

AB/AH36

AB/DH36

AB/EH36

AB/FH36

AB/AH40

AB/DH40

AB/EH40

AB/FH40

Extra Strength

AB/AQ43

AB/DQ43

AB/EQ43

AB/FQ43

AB/AQ47

AB/DQ47

AB/EQ47

AB/FQ47

AB/AQ51

AB/DQ51

AB/EQ51

AB/FQ51

AB/AQ56

AB/DQ56

AB/EQ56

AB/FQ56

AB/AQ63

AB/DQ63

AB/EQ63

AB/FQ63

AB/AQ70

AB/DQ70

AB/EQ70

AB/FQ70

 

 

ABS DQ51 thickness and impact requirements

For ABS DQ51 the Charpy V-notch test is run at -20°C with a minimum average of 50 J longitudinal or 33 J transverse. The requirement does not change with thickness the way it does for hull grades; the maximum thickness depends on the supply condition and the mill approval (ABS 2-1-8, Table 3). Confirm the thickness limit with the mill approval before ordering.

ABS DQ51 equivalent grades
Standard / society Equivalent grade
ABS AB/DQ51
IACS UR W16 D500
DNV VL D500
Other IACS societies (LR, BV, CCS, NK, KR, RINA) D500 with the society's own prefix
ASTM A131 no equivalent (A131 stops at 390 MPa)

Grades are equivalent in chemistry and properties because the IACS societies use the same unified requirements. A plate still needs a certificate from the vessel's own classification society, so one plate can carry dual or multiple class certification only when each society's surveyor tests it.

FAQ

What does DQ51 mean?

DQ sets the Charpy test temperature (-20°C), and 51 is the strength level: minimum yield 500 MPa.

What are the mechanical properties of ABS DQ51?

Minimum yield 500 MPa, tensile strength 610-770 MPa and minimum elongation 16%. Charpy average at -20°C is at least 50 J longitudinal or 33 J transverse.

What is the impact test temperature of ABS DQ51?

-20°C.

What is ABS DQ51 equivalent to?

Grade D500 in IACS UR W16 (DNV VL D500). ASTM A131 has no equivalent at this strength. The plate must be certified by the vessel's classification society.

How is ABS DQ51 supplied?

Quenched and tempered (QT) or thermo-mechanically rolled (TM). The chemistry limits and maximum thickness depend on the supply condition (ABS 2-1-8, Tables 3 and 4A).

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