Steel Plate for Hull Structure (GB7 12-88). There are two types of hull structural steel: ordinary thickness steel and high strength steel. General strength steel is divided into four grades according to quality: A, B, C and D; High strength steel is divided into two strength grades and three quality grades; AH32、DH32、EH32、AH36、DH36、EH36。 Steel plates for hull structure are mainly used to manufacture steel plates for hull and deck of marine, coastal and inland transport ships. Product specifications: the thickness is 4.5-50mm, the width is 1.0-2.2mm, and the length is 4.0-12.0m. China is mainly produced by WISCO, Masteel, No.1 and No.3 Plant of Shanghai Steel, Taigang, Kungang and Tiangang.