The preservation of seafood is actually based on low temperatures.
By quick freezing, stored at minus 18 °C,
Not only can it better retain the original quality of seafood,
But it is also conducive to long-term preservation and transportation.
Today's hard dish,
Also needs cryopreservation and transportation,
But minus 18°C is not ok,
At least minus 162 ° C.
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This "dish" is - iced natural gas! Natural gas is a gas at room temperature and pressure, and only when it is cooled to minus 162 ° C, it will change to a liquid. China imports a lot of natural gas every year, and these natural gases are liquefied and crossed the ocean on a special freighter to come to our side of the "seafood".
Today's focus is not on liquefied natural gas, but on the "extremely fresh" steel can containing liquefied natural gas! At the extreme low temperature of minus 162 ° C, ordinary steel is as brittle as a biscuit, and it will shatter when touched, and it is impossible to hold liquefied natural gas. But there is a special steel is not afraid of the cold, this steel inside the 9% of the metal nickel, in minus 162 ° C still has good toughness and strength, known as the diamond of the steel industry, the scientific name of nine nickel steel! This high-end special steel can only be imported. 10 years ago, the import of one ton of nine-nickel steel required more than 20 times the price of ordinary steel plates. In order to overcome this "card neck" technology, our national "Iron Man" has carried out technical research for up to 15 years!
After oxidation, nickel will adhere to the surface of the steel, resulting in a fish-like iron oxide sheet on the surface of the steel, forming a large number of uneven small gaps. If it is made into a storage tank, the liquefied natural gas comes into contact with these gaps, which will cause cracks in the steel plate, causing natural gas to leak and even cause an explosion. Moreover, the storage tank made of liquefied natural gas also requires a lot of welding, and if any one of the welds is flawed, it may also lead to natural gas leakage and even a big explosion.
Therefore, the research and development requirements of nine nickel steel are extremely high and extremely difficult. However, after 15 years of struggle, our "Iron Man" now has the most stable and mature nickel steel production process and production line, and has taken off this pearl in the steel industry!
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(Edited by Sun Yonghui)