Difference between LR DH46 and LR DH50 steel plate

Dec 18, 2025 Leave a message

LR DH46 and LR DH50 are Lloyd's Register (LR) classified shipbuilding steels, with the primary difference being their strength: DH46 offers a minimum yield strength of 460 MPa, while DH50 provides higher strength with a minimum yield of 500 MPa, achieved through similar controlled compositions but differing amounts of alloying elements (like C, Mn, Si) and strict heat treatments (normalized) for enhanced toughness and weldability in marine structures, making DH50 suitable for more demanding applications.

LR: Lloyd's Register, the classification society.

D: High Strength.

H: Normalized (Heat Treated).

46/50: Minimum Yield Strength in kgf/mm² (or 460/500 MPa).

Chemical Composition

LR DH46 extra high Strength Chemical Composition
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	Al	N
LR DH46	0.20	0.55	1.70	0.030	0.030	0.015	0.020
	Nb	V	Ti	Cu	Cr	Ni	Mo
	0.02-0.05	0.03-0.10	0.02

LR DH50 extra high Strength Chemical Composition
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	Al	N
LR DH50	0.20	0.55	1.70	0.030	0.030	0.015	0.020
	Nb	V	Ti	Cu	Cr	Ni	Mo
	0.02-0.05	0.03-0.10	0.02

Mechanical Property

LR DH46 extra high strength property
Grade		Mechanical Property			Charpy V Impact Test
Grade	Thickness	Yield	Tensile	Elongation	Degree	Energy 1	Energy 2
LR DH46	mm	Min Mpa	Mpa	Min %	-20	J	J
	t≤50	460	570-720	19%		31	46
	50＜t≤70	460	570-720	19%		31	46
	70＜t≤100	460	570-720	19%		31	46
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal

LR DH50 extra high strength property
Grade		Mechanical Property			Charpy V Impact Test
Grade	Thickness	Yield	Tensile	Elongation	Degree	Energy 1	Energy 2
LR DH50	mm	Min Mpa	Mpa	Min %	-20	J	J
	t≤50	500	610-770	18%		33	50
	50＜t≤70	500	610-770	18%		33	50
	70＜t≤100	500	610-770	18%		33	50
Note: Energy 1 is transverse impact test, Energy 2 is longitudinal

Equivalent steel grade

Equivalent steel grade of LR DH46
DNV	GL	ABS	BV	CCS	NK	KR	RINA
NV D460	GL-D460	AB/DQ47	BV/D460	CCS/D460	K D47	R D47	RI/D460

Equivalent steel grade of LR/DH50
DNV	GL	ABS	BV	CCS	NK	KR	RINA
NV D500	GL-D500	AB/DQ51	BV/D500	CCS/D500	K D51	R D51	RI/D500