The AH designation is not a standard steel grade in our country, but rather an international standard, specifically indicating the grade of shipbuilding steel, which is a professional grade designation. AH36/DH36H ship plates denote high strength, with '36' representing 360MPa, 'A' denoting the grade of steel, which can be divided into four grades: A, B, D, E.
DH36 is a type of low-alloy high-strength ship plate steel. This grade of steel, based on low-carbon steel, is enhanced in strength and low-temperature impact toughness by adding various alloying elements such as Nb, Ti, Ni, Mn, etc. (usually in amounts less than 3%). Additionally, this steel is corrosion-resistant, fatigue-resistant, has low carbon equivalent, and exhibits good welding and forming properties. Therefore, DH36, as one of the higher quality grades of steel, is commonly used in the construction of large ships, offshore oil platforms, drilling platforms, etc., to withstand harsh marine environments. Here, 'D' represents the grade of steel, 'H' denotes high strength, and '36' signifies a yield strength not less than 360 MPa.
As offshore platforms, especially self-elevating ones, are increasingly becoming larger, there is a demand for thick plates with tensile strength up to 800MPa and thicknesses ranging from 125 to 350mm. Increasing thickness not only poses welding difficulties but also significantly affects strength and low-temperature toughness. During rolling, due to minimal intermediate deformation and low cooling rates, coarse grains result in lower strength and toughness. While thick plates produced through quenching and tempering processes enhance alloy content, they also affect welding performance. Therefore, proper composition design involving the addition of microalloying elements like niobium, vanadium, titanium, and controlling the parameters of Thermo-Mechanical Controlled Processing (TMCP) is crucial in thick plate production. For D-grade plates with thickness >24mm, and for American Bureau of Shipping (ABS) DH36 ship plates with thicknesses ranging from 6-50mm, the designation is appended with the letter 'N', such as AB/DN or AB/DH36N; D-grade ship plates with thicknesses from 6-≤24mm remain as AB/D.
The DH36 ship plate conforms to the standard GB/T712-2011, with an impact temperature of -20 degrees Celsius, and additional requirements for plate thickness direction performance, namely, Z-direction performance. Following Z-direction performance, it is denoted as DH36-Z35. The delivery condition of DH36 ship plates includes annealing, hot rolling, normalizing, controlled rolling, and TMCP (different thicknesses correspond to different delivery conditions).
Produced by Chinese iron and steel enterprises, DH36 ship plates can be manufactured according to different national specifications for shipbuilding steel, such as those of the United States, Norway, Japan, Germany, France, etc., including CCS, ABS, GL, BV, DNV, KDK, LR specifications.
The production process for DH36 ship plates includes: converter—ladle furnace—vacuum degassing—continuous casting—stack cooling—slab inspection—heating—high-pressure water descaling—rough rolling—finish rolling—ACC cooling—hot straightening—finishing—plate inspection—warehousing. Supply can be made according to standards such as national standards, Metallurgical standards, American standards AISI/ASME/ASTM, Japanese standards JIS, German standards DIN, French standards NF, British standards BS, European standards EN, and international standards ISO.
Our products are mainly used in national major technical equipment projects, national defense and military industry, and important sectors of the national economy. We can produce a variety of steel plates, including boiler and pressure vessel steel plates, low-alloy high-strength steel plates, corrosion-resistant steel plates, bridge steel plates, steel plates for high-rise building structures, alloy structural steel plates, mold steel plates, shipbuilding and oil platform steel plates, composite steel plates, high-strength and high-toughness steel plates, and steel plates for oil and gas pipelines, comprising twelve major series and more than 200 grades, with thickness specifications of over 300. Our products feature wide and smooth surfaces, neat edges, and are sold nationwide.
DH36 ship plates are high-strength structural steel plates used for high-strength shipbuilding. Shipbuilding steel generally refers to steel used for ship structural purposes, manufactured according to the requirements of classification societies for the production specifications. It is often ordered, scheduled, and sold as specialty steel for a ship, including ship plates, shaped steel, etc.
Baoshan District,
Shanghai, China.
