Structural steel for hull is divided into strength grades according to its minimum yield point: general strength structural steel and high strength structural steel. Ship plate refers to the hot-rolled steel plate used to manufacture the hull structure produced in accordance with the requirements of the classification society's construction rules. The general-strength structural steels in the standards of China Classification Society are divided into four quality grades: A, B, D, and E (namely CCSA, CCSB, CCSD, CCSE); the high-strength structural steels in the standards of China Classification Society are three Intensity levels, four quality levels.