Introduction to Shipbuilding Steel

Shipbuilding steel generally refers to the steel used for hull structure, which refers to the steel used to manufacture the hull structure produced in accordance with the requirements of the construction specifications of the classification society. It is often used as special steel to order, schedule and sell, and a ship includes ship plates, section steel, etc.

At present, several major iron and steel enterprises in my country have production, and can produce marine steel according to the needs of users in different countries, such as the United States, Norway, Japan, Germany, France, etc. The specifications are as follows:

country	China	U.S	Germany	France	Norway	Japan	U.K
Specification	CCS	ABS	GL	BV	DNV	KDK	LR

Structural steel for hull is divided into strength grades according to its minimum yield point: general-strength structural steel and high-strength structural steel.

The general-strength structural steel according to the rules and regulations of China Classification Society is divided into four quality grades: A, B, D, and E;
The high-strength structural steel specified by China Classification Society has three strength levels and four quality levels:

A 32	A 36	A 40
D 32	D 36	D 40
E 32	E 36	E 40
F 32	F 36	F 40

Mechanical properties and chemical composition of general strength hull structural steel

Grade	Yield point σ s (MPa)	tensile strength σ b (MPa)	Elongation σ%	C	Mn	Si	S	P
A	235	400-520	22	≤0.21	≥2.5C	≤0.5	≤0.035	≤0.035
B	≤0.21	≥0.80	≤0.35
D	≤0.21	≥0.60	≤0.35
E	≤0.18	≥0.70	≤0.35

Mechanical properties and chemical composition of high-strength hull structural steel

Grade	Yield point σ s (MPa)	tensile strength σ b (MPa)	Elongation σ%	C	Mn	Si	S	P
A 32	315	440-570	22	≤0.18	≥0.9-1.60	≤0.50	≤0.035	≤0.035
D 32
E 32
F 32	≤0.16	≤0.025	≤0.025
A 36	355	490-630	21	≤0.18	≤0.035	≤0.035
D 36
E 36
F 36	≤0.16	≤0.025	≤0.025
A 40	390	510-660	20	≤0.18	≤0.035	≤0.035
D 40
E 40
F 40	≤0.16	≤0.025	≤0.025

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