What are difference between LR DH46 and LR DH50 steel plate

Jan 06, 2026 Leave a message

LR DH46 and LR DH50 are both high-strength, heat-treated (DH) marine structural steels approved by Lloyd's Register (LR), but LR DH50 offers significantly higher strength (around 500 MPa yield) compared to LR DH46 (around 460 MPa yield), making DH50 suitable for more demanding structural applications where greater load-bearing capacity and toughness are required, though both provide good weldability and performance in marine environments, differing mainly in their mechanical properties due to specific alloy composition and heat treatment.

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

Strength Level:

LR DH46: Offers a minimum yield strength of approximately 460 MPa (megapascals).

LR DH50: Offers a higher minimum yield strength, typically around 500 MPa.

Grade Designation:

The "46" and "50" in the names directly correspond to their minimum yield strength in tens of megapascals (MPa).

Applications:

LR DH46: Used in general shipbuilding and offshore structures where good strength and toughness are needed.

LR DH50: Used for more critical, high-stress areas of ships, offshore platforms, and other marine constructions requiring enhanced strength and impact resistance.

Properties: Both grades are designed for shipbuilding and marine use, providing good weldability and formability, but DH50 provides superior mechanical properties for heavier-duty service.