High-strength AH36/DH36 shipbuilding steel plate Composition optimization test

1.1 High-strength AH36/DH36 shipbuilding steel plate Process

High-strength AH36/DH36 shipbuilding steel plate introduced in this paper adopts the traditional rolling process. The production process of High-strength AH36/DH36 shipbuilding steel plate is: 100 t converter - argon blowing station - LF refining - 200 mm slab continuous casting - blank cutting - heating - descaling - 2800 mm Plate mill rough rolling - 2800 mm rolling mill finishing - straightening - cooling - shearing - collection and storage.

1.2 High-strength AH36/DH36 shipbuilding steel plate Composition optimization program

According to the solidification theory, the slab is preferentially crystallized during the solidification process, and the part of the compound rich in C, P, S, Mn and the compound is often squeezed to the center of the slab and finally solidified. The solidification is the part with severe segregation, which affects the continuity of the metal structure and becomes one of the main causes of the problem of High-strength AH36/DH36 shipbuilding steel plate performance.
Therefore, it is considered that the H36/DH36 shipbuilding steel plate fracture is caused by the central segregation mainly caused by manganese segregation. In actual production, the content of C, P and S elements in H36/DH36 shipbuilding steel plate has been relatively low. Only reduce the manganese content to reduce the central segregation caused by element segregation, improve the fracture morphology and improve the fracture rate, but at the same time ensure the strength performance. The main measures are to reduce the manganese content of High-strength AH36/DH36 shipbuilding steel plate. The control range of High-strength AH36/DH36 shipbuilding steel plate manganese content is reduced from 1.20 to 1.45 to 1.15 to 1.30, respectively. The actual control range of manganese content of High-strength AH36/DH36 shipbuilding steel plate is 1.21～ 1.28; and carried out batch production test, the specific composition is shown in Table 1.

Table 1 The actual composition of the High-strength AH36/DH36 shipbuilding steel plate after manganese reduction