What are difference between ABS DQ47 and ABS DQ51?

Jan 27, 2026 Leave a message

ABS DQ47 and ABS DQ51 are high-strength quenched and tempered (DQ) steel grades designated by the American Bureau of Shipping (ABS) for shipbuilding, particularly in offshore platforms and structural engineering. The primary difference is the strength level, with DQ51 offering higher yield strength compared to DQ47, designed for deeper water or heavier loads.

Chemical Composition

ABS DQ47 Extra high Strength Chemical Composition in Tempering and Quenching
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	N
ABS DQ47	0.20	0.55	1.7	0.035	0.035	0.02

ABS DQ51 Extra high Strength Chemical Composition in Tempering and Quenching
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	N
ABS DQ51	0.20	0.55	1.7	0.030	0.030	0.02

Mechanical Property

ABS DQ47 Extra high strength property in tempering and quenching
Grade	Mechanical Property			Charpy V Impact Test
	Yield	Tensile	Elongation	Degree	Energy 1	Energy 2
	Min Mpa	Mpa	Min %	-20	J	J
ABS DQ47	460	570-720	17	-20	31	46
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal

ABS DQ51 Extra high strength property in tempering and quenching
Grade	Mechanical Property			Charpy V Impact Test
	Yield	Tensile	Elongation	Degree	Energy 1	Energy 2
	Min Mpa	Mpa	Min %	-20	J	J
ABS DQ51	500	610-770	16	-20	33	50
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal

Yield Strength: ABS DQ51 provides a minimum yield strength of 500 MPa, higher than the 470 MPa+ minimum expected for DQ47, making it suitable for applications needing higher resistance to deformation.

Applications: Both are used for severe service, but ABS EQ51 (equivalent to DQ51 with higher impact requirements) is often utilized in critical offshore drilling platforms and specialized shipbuilding.

Grade Equivalents: While DQ51 is equivalent to grades like CCSEH500 and BVEH500, DQ47 represents a lower, yet still high-strength, tier.