9% Ni steel is W( Ni) -9% low carbon tool alloy relieved as well as tempered steel created by the American International Nickel Company in 1944. Its structure is Martensite as well as Bainite. This steel has good sturdiness as well as high stamina at really low temperature level, the thermal development coefficient is small compared with Austenitic stainless steel and also light weight aluminum alloy, the most affordable temperature can reach a 196 ℃. The 5% Ni steel established based on 9Ni steel likewise has great reduced temperature durability at the low temperature of -162 ~ -196 ℃.
The primary features of this steel are high nickel content, high pureness, high toughness, high low temperature level influence strength, excellent weldability. In 1952, the initial 9Ni steel storage tank on the planet was put into use in the United States. In 1960, the study showed that 9Ni steel without post-weld stress alleviation heat treatment might be made use of safely. Ever since, 9Ni steel has actually turned into one of the main products made use of in the manufacture of huge cryogenic storage tanks. The first LNG storage tank built in Japan in 1969 has a maximum ability of 20 × 104m ³.
The 9% Ni steel plate is the typically used form for this steel, and also the steel plate have some requirements worldwide such as ASME: SA-353, EN 10028, JIS G3127, GB 24510 and 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 low temperature level mostly depend on its chemical structure, particularly the components of Ni and C. On top of that, the toughness of 9Ni steel additionally relies on the purity and also microstructure of the steel. The 8.50 ~ 9.50 Ni web content ensured the hardenability to a particular degree. The decrease of carbon material can substantially minimize the precipitation of carbides in tempered martensite, hence boosting the low temperature level toughness, while the high carbon content will result in major deterioration of welding residential properties and also cool fragile residential properties. Therefore, in the alloying process, the web content of C must be purely regulated to maintain it in the low carbon array, as well as at the very same time, the web content of P, S, Mn, Mo, Cr as well as various other alloying components need to additionally be managed in the reduced variety. The material of alloying elements as well as contamination is a crucial factor affecting the fragile transition temperature of 9Ni steel.
We know that the liquefaction temperature of natural gas is -162 ℃, and also the volume of liquefied natural gas (LNG) is 1/600 of the gaseous state, which has higher demands on the material of LNG tank. Presently the materials used in LNG tank generally are 9 Ni steel, 5 Ni, Austenitic stainless-steel, Aluminium magnesium alloy steel, and so on, and the most wldsteel co.,ltd affordable temperature can reach 9 Ni steel - 196 ℃, its high toughness, superb reduced temperature level sturdiness, excellent welding efficiency, simple to processing advantages, making it commonly utilized in the manufacture of LNG container as well as transportation ships, is the very best of the cryogenic atmosphere making use of the sturdiness of materials.