Development of new 7%Ni steel for LNG storage tanks

Considering the scarcity of nickel in China and cost-saving for construction of LNG storage tanks, it is very significant to develop a new generation of low-nickel steel for storage tanks. Herein, the material performance and weldability of the new low-nickel (7%Ni) steel were analyzed by tests. The results indicate that the 7%Ni steel plate has high strength and toughness, with a tensile strength of 690-730 MPa and a low-temperature impact energy of 150-200 J at-196 ℃, and the welded joints have good comprehensive performance. Definitely, the tensile strength of the welded joints is no less than 690 MPa, the impact energy of the welds and the heat affected zones is not less than 80 J, and the hardness of the base material and the heat affected zones is not greater than 340 HV10. Generally, the performance of the new 7%Ni steel plate for LNG storage tanks satisfies the technical requirements for the construction and welding of LNG storage tanks.