抄録
Steel intended for use as the hull materials of deep submergible vehicles has been developed. The target properties of the steel were minimum yield strength of 900 MPa and high toughness.
The primary research was conducted on several steels containing a range from 2.5 to 5% Ni with the emphasis on mechanical properties, heat treating characteristics and weldability. The optimum chemical composition of steel having the above-mentioned properties has been formed to be 0.09C-5Ni-0.5Cr-0.5Mo-0.05V with minimal impurities, especially, low sulfur content. Production heats of this steel were conducted. Slab was made by electroslag remelting process for having ultra low impurities and super cleanliness. Plates of quenched and tempered steel of 65mm in thickness exhibited yield strength having a range from 931 to 960 MPa, and Charpy V-notch shelf energy absorption having a range from 172 to 209J.
According to this good quality, this steel plate was applied for the hull material of deep submergible vehicle (“Shinkai 2000”) operating in seas of 2000m depth.
