In order to reduce the cost, it is better to produce KR grade E shipbuilding steel by hot rolling or controlled rolling instead of normalizing. For kre steel plate with thickness less than 35mm, two-stage controlled rolling has been adopted; for KR grade E shipbuilding steel with thickness greater than 35mm, it is mostly produced by hot rolling and normalizing.
In order to ensure the performance of KR grade E shipbuilding steel, microalloying technology is adopted. By adding Nb, V, Ti and other alloy elements into KR grade E shipbuilding steel, combined with controlled rolling process, grain refinement and improvement of strength and toughness of KR grade E shipbuilding steel are achieved.
KR grade E shipbuilding steel is required to have good low temperature toughness and good welding performance. Firstly, the smelting process of KR grade E shipbuilding steel should be guaranteed, and then effective controlled rolling and cooling process should be implemented. In recent years, the major domestic iron and steel enterprises have fully realized the importance of improving the internal quality of KR grade E shipbuilding steel.
Relying on the progress of smelting technology, it has improved on hot metal desulfurization and slag removal, steel-making hydrogen blowing, and external vacuum refining, which has significantly reduced the content of harmful elements and impurities in KR grade E shipbuilding steel.
