Performance requirements of Marine Engineering DH36 steel

Because offshore platforms are immersed in seawater all the year round, they have to endure all kinds of bad sea conditions. Therefore, the technical specifications of DH36 steel used for offshore platforms are very high. It requires not only high atmospheric corrosion resistance and seawater corrosion resistance, but also good mechanical and processing performance. The performance requirements of offshore platform DH36 steels include:

(1) DH36 steel should have high strength to resist air impact. It has good resistance to lamellar tear and prevents DH36 steel from tearing when it is subjected to external force in thickness direction.

(2) DH36 steel should have good low temperature impact properties.

(3) DH36 steel should have good weldability, and the welded joint has the same or similar mechanical properties as the base metal to ensure the safety of the overall structure of the offshore platform.

(4) DH36 steel purity requirement. DH36 steel should have a low content of impurity elements such as P and S, and have a high requirement on the morphology, type and distribution of inclusions, so as to avoid fatigue failure of offshore platforms under the influence of typhoon and current movement, and to ensure the safety of life and property.

(5) Requirements for corrosion resistance of DH36 steel. Because the marine DH36 steel structure has been in the environment of salt fog, humidity and sea water for a long time, and is eroded by sea water and marine organisms, it produces intense electrochemical corrosion. The paint film is prone to severe saponification and aging, resulting in very serious structural corrosion, which reduces the mechanical properties of structural materials, shortens their service life. Because it is far away from the coast, it cannot be repaired and maintained regularly like ships. Therefore, the requirements for DH36 steel corrosion resistance are even higher.