Physical Metallurgy and Commercialization of V-N Microalloyed Q460GJC Steel Plates

For the purpose of reducing alloys additions and then its cost of conventionally combined Nb-V microalloyed Q460 grade steel plates for construction, a HSLA steel alloying design with only V-N microalloying of 0.06–0.08%V and free of niobium, and corresponding thermal mechanical controlled process were facilitated by better understanding the third generation TMCP concept and V-N microalloying technology. These resulted in successfully commercializing gauge 50mm V-N microalloyed Q460GJC steel plates with good combination of high strength >470MPa and improved toughness of Akv@0°C>150 J, and low YS/UST ratio of 80% as well. Theoretical calculation indicated that the contribution by fined-grain and precipitate strengthening amount to ~66% of yield strength of the newly developed plate steels.