According to its minimum yield point, the structural steel for ship plate, that is, the structural steel for the hull, is divided into the following strength classes: general-strength structural steel and high-strength structural steel. Ship plate refers to the hot-rolled steel plate produced in accordance with the requirements of the construction rules of the classification society for the manufacture of ship hull structures. The general-strength structural steel of the China Classification Society standard is divided into four quality grades: A, B, D, and E (ie CCSA, CCSB, CCSD, CCSE); the high-strength structural steel of the China Classification Society standard is three Strength levels, four quality levels.

One: ship class specification

The main classification society rules are:
China CCS
American ABS
Germany GL
French BV
Norway DNV
Japan NK
UK LR
Korea KR
Italian RINA

Two: Variety Specifications
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 of the China Classification Society standard is divided into four quality grades: A, B, D, and E; the high-strength structural steel of the China Classification Society standard is three strength grades and four quality grades:

A32 D32 E32 F32 ≤50mm Carbon equivalent Ceq,% not more than 0.36>50-100 Carbon equivalent Ceq,% not more than 0.4A36 D36 E36 F36 ≤50mm Carbon equivalent Ceq,% not more than 0.38>50-100 Carbon equivalent Ceq,% not More than 0.4A40 D40 E40 F40≤50mm Carbon equivalent Ceq,% not more than 0.4>50-100 Carbon equivalent Ceq,% Non-carbon equivalent calculation formula C eq（%）=C+Mn/6 +(Cr+Mo+V)/ 5 +(Ni+Cu)/15…..Remarks: Carbon equivalent refers to converting the effect of various alloying elements in steel on the actual carbon content of the eutectic point into the increase or decrease of carbon.

3. Introduction of ship plate The general strength steel for hull structure is divided into four grades: A, B, D and E. The yield strength (not less than 235N/mm^2) and tensile strength (400～520N/ mm^2) is the same, but the impact energy at different temperatures is different; high-strength hull structural steel is divided into strength grades according to its minimum yield strength, and each strength grade is divided into A, D, E according to its impact toughness. , F4 level. The yield strength of A32, D32, E32 and F32 is not less than 315N/mm^2, and the tensile strength is 440～570N/mm^2. -40°, -60° impact toughness; yield strength of A36, D36, E36, F36 is not less than 355N/mm^2, tensile strength is 490～620N/mm^2, A, D, E and F represent the impact toughness that can be achieved at 0°, -20°, -40°, and -60° respectively; the yield strength of A40, D40, E40, and F40 is not less than 390N/mm^ 2. The tensile strength is 510～660N/mm^2, and A, D, E, and F represent the impact toughness that can be achieved at 0°, -20°, -40°, and -60° respectively.

Four: mechanical properties