LNG ships are called "super-refrigerated vehicles on the sea", and their service environment is at a very low temperature of minus 163 degrees Celsius. This requires that the steel for LNG storage tanks must have low temperature resistance, often using Invar steel or 9Ni steel. At present, a complete series of nickel steels such as 0.5Ni steel, 2.5Ni steel, 3.5Ni steel, 5Ni steel, and 9Ni steel have been formed in the field of low-temperature steel. China has also developed relatively mature 3.5Ni steel and 5Ni steel. And 9Ni steel, and successfully used in the construction of low-temperature transport ships.
In March, the daily output of key iron and steel enterprises decreased on a month on month basis. In terms of enterprise inventory, in late March, the key statistics showed that the A387 Gr.12 Class2 astm standard steel inventory of iron and steel enterprises was 18.067 million tons, a decrease of 3.342 million tons or 15.6% compared with the highest inventory in early March, and an increase of 8.534 million tons or 89.5% compared with the beginning of the year.
How to distinguish the inferior steel plate? 1. The surface of the fake and inferior steel plate is easy to produce scab. 2. The material of fake and inferior steel plate is not uniform and there are many impurities. The surface of fake and inferior steel plate is often pitted. Pitting is an irregular and uneven defect on the surface of A387 Gr.12 Class2 astm standard, steel plate caused by serious wear of rolling groove. Due to the pursuit of profit by the manufacturers of fake and inferior steel plates, the groove rolling often exceeds the standard.
The mooring chain is immersed in seawater for a long time and the service environment is harsh. Therefore, it must have high strength, good toughness, seawater corrosion resistance, fatigue resistance, wear resistance, etc., and in practical applications, it usually needs to be bent into a ring. Therefore, it is necessary to have good cold bending and welding performance. At present, China has successfully developed the world's first R6 mooring with the highest strength level, and realized its application, leading the development of the latest generation of marine mooring chains.