The characteristic of niobium in AH36 steel for offshore oil drilling platforms etc., is to increase the recrystallization temperature of austenite, so as to achieve the purpose of refining austenite grains. In general, the amount of niobium added in steel material is less than 0.05%, and the contribution of niobium above 0.05% to strengthening and toughening will no longer be obvious.
Flat steel is a kind of steel with rectangular cross-section and blunt edges at the edges and corners. It is usually 12-300 mm wide and 3-60 mm thick. Compared with AH36 steel for offshore oil drilling platforms ordinary steel plate, the utilization rate of flat steel is increased by one to five percentage points. Moreover, flat steel can be produced with fixed thickness, width and length according to the user's requirements, which saves the cutting process for users, reduces the consumption of labor and materials, and also reduces the processing loss of raw materials, saving time, labor and material.