Buy Offshore and Shipbuilding Steel Plate from AGICO
Angang's steel grade covers the large-strength energy welding ship and the marine oil platform steel series of ordinary strength A, B, D, E and high strength AH32～EH32, AH36～EH36, AH40～EH40. The maximum thickness of the product is 100mm, the welding line energy is 100kJ/cm. Its strength, low temperature toughness, specifications and other indicators have reached the international advanced level, which greatly exceeds the thickness of 40mm and the welding line energy of 50kJ/cm which can be achieved by ordinary steel mills.
Relying on the new generation of controlled rolling and controlled cooling technology of hot rolled strip steel, Northeastern University independently developed the first set of advanced rapid cooling equipment and control system for hot rolled steel. This equipment has become the main model of hot rolled steel production line in China, covering More than 50% of large steel enterprises such as Anshan Iron and Steel and Shougang have achieved a production scale of 40 million tons/year of high-quality and economical hot-rolled steel. The products developed in the West-East Gas Pipeline, Ocean Platform, Sea-crossing Bridge, and Third-generation Nuclear Power Plant Widely used in national strategic projects such as large surface ships.
Chemical Composition Requirements for Offshore OCTG steel
The factors affecting the performance of steel are: chemical composition, smelting and casting, rolling and heat treatment processes, etc., mainly chemical components; sulfur and phosphorus content directly affect the performance of the thickness direction of the steel plate. Sulfur is the most severe element of segregation in continuous casting billets. Sulfur can cause hot brittleness of the steel, causing cracks in the steel at high temperature forging. Produces many loose and vent holes during welding.
Phosphorus is an element which is second only to sulfur in the continuous casting of steel, and the diffusion rate of phosphorus in iron solid solution is small, so the segregation of phosphorus is difficult to eliminate, which seriously affects the performance of steel. Phosphorus is dissolved in ferrite in the form of a solid solution. This solid solution is very brittle, and the formed phosphorus-rich region promotes brittleness of the steel and reduces the plasticity, toughness and weldability of the steel. It is easy to cause cracking of steel during hot working, and cracks are likely to occur during welding. Phosphorus is an element that lowers the surface tension of steel. As the phosphorus content increases, the surface tension of the molten steel decreases significantly, thereby reducing the crack resistance of the steel.
Therefore, the steel plate for offshore platforms and shipbuilding steel has strict requirements on the content of sulfur and phosphorus, and the content of sulfur is strictly controlled.
