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I. Introduction to 06Ni9DR: The 06Ni9DR (9%Ni) steel plate is used for low-temperature pressure vessels specifically designed for LNG storage tanks; it is a low-temperature pressure vessel steel plate suitable for temperatures down to -196°C. Thanks to its excellent resistance to low-temperature impact and extremely low coefficient of thermal deformation, it is widely used in LNG carriers and LNG storage and transportation projects. Other grades in this series include 08Ni3DR (3.5% nickel), 08Ni5DR (5% nickel), and 06Ni9DR (commonly known as 9% nickel steel). II. Execution standard for 06Ni9DR: GB24510-2009 – 9%Ni steel plates for low-temperature pressure vessels. The inspection procedures are specified in JB/T4730.3-2005 – Non-destructive testing of pressure equipment. III. Delivery condition of 06Ni9DR: The steel plates are delivered in a quenched and tempered state after offline heat treatment. To improve the toughness of the steel, intermediate heat treatment (secondary quenching) can also be carried out; for steel plates with a thickness of no more than 12 mm, they can also be delivered in a double normalizing and tempering state. The tempering temperature for these steel plates must be no less than 540°C. IV. Chemical composition of 06Ni9DR: C: ≤ 0.1; Si: ≤0.35; Mn: 0.30–0.80; Mo: ≤0.10; P: ≤0.010; S: ≤0.004; Ni: 8.5–10; V: ≤0.01. V. Mechanical properties of 06Ni9DR: Yield strength Rel (MPa): 680–820; for thicknesses of 5–30 mm, Rel ≥ 585 ； Thickness > 30 mm; Rel ≥ 575. Elongation A (%): ≥ 18. Cold bending test: b = 2a, 180°; d = 3a. Applications of 06Ni9DR: As global energy resources become more diversified, there will be a high demand in China for materials used in LNG terminal structures in the future. Developing materials suitable for such structures will be an important part of adjusting energy strategies. The temperature of LNG is -162°C, requiring its structural materials to possess certain strength and toughness at such extremely low temperatures. Currently, the main materials for ultra-low temperatures include austenitic stainless steels, nickel-based alloys, aluminum alloys, and 9Ni steel. Compared to austenitic stainless steels and austenitic iron-nickel alloys, 9Ni steel is less costly; moreover, it possesses better mechanical properties than aluminum alloys. Therefore, 9Ni steel is widely used internationally as the structural material for LNG storage and transportation equipment. Among them, 9Ni steel is the only ferritic low-temperature steel that can be used at -196 °C; its Charpy impact energy at this temperature ranges from 200 to 230 J, making it the material with the best toughness for use in cryogenic environments.