9% Ni steel is W( Ni) -9% low carbon tool alloy satiated and also solidified steel developed by the American International Nickel Company in 1944. Its structure is Martensite and Bainite. This steel has excellent toughness and high strength at really low temperature, the thermal expansion coefficient is small compared with Austenitic stainless-steel and aluminum alloy, the most affordable temperature level can get to a 196 ℃. The 5% Ni steel created based upon 9Ni steel likewise has great reduced temperature sturdiness at the reduced temperature level of -162 ~ -196 ℃.
The primary characteristics of this steel are high nickel content, high pureness, high stamina, high low temperature impact durability, excellent weldability. In 1952, the very first 9Ni steel storage tank in the world was taken into use in the United States. In 1960, the study proved that 9Ni steel without post-weld stress and anxiety relief warmth treatment can be utilized securely. Ever since, 9Ni steel has turned into one of the major products used in the manufacture of big cryogenic storage tanks. The very first LNG tank built in Japan in 1969 has a maximum ability of 20 × 104m ³.
The 9% Ni steel plate is the commonly made use of shape for this steel, and also the steel plate have some specification worldwide such as ASME: SA-353, EN 10028, JIS G3127, GB 24510 as well as others.
EN 10028-4: X8Ni9+ NT640/ X8Ni9+ QT680.
JIS G3127: SL9N520/SL9N590.
ASME: SA-353/ SA-553-1.
GB 24510: 9Ni490/ 9Ni590A.
The mechanical buildings of 9Ni steel at reduced temperature generally rely on its chemical composition, especially the materials of Ni as well as C. Furthermore, the toughness of 9Ni steel likewise depends upon the pureness and microstructure of the steel. The 8.50 ~ 9.50 Ni content guaranteed the hardenability to a certain degree. The reduction of carbon material can significantly reduce the precipitation of carbides in solidified martensite, therefore enhancing the low temperature toughness, while the high carbon web content will certainly lead to severe degeneration of welding residential or commercial properties and also chilly brittle homes. For that reason, in the alloying process, the content of C must be strictly controlled to maintain it in the low carbon array, and also at the exact same time, the content of P, S, Mn, Mo, Cr as well as various other alloying components must likewise be regulated in the low variety. The web content of alloying elements as well as impurity is a crucial factor impacting the brittle transition temperature level of 9Ni steel.
We know that the liquefaction temperature of natural gas is -162 ℃, and also the quantity of liquefied natural gas (LNG) is 1/600 of the gaseous state, which has greater demands on the product of LNG tank. Currently the materials made use of in LNG container primarily are 9 Ni steel, 5 Ni, wldsteel.com Austenitic stainless steel, Aluminium magnesium alloy steel, and so on, and the most affordable temperature level can reach 9 Ni steel - 196 ℃, its high stamina, superb low temperature level sturdiness, excellent welding performance, very easy to refining advantages, making it extensively utilized in the manufacture of LNG storage tank and transportation ships, is the most effective of the cryogenic setting using the toughness of materials.