The invention discloses ultra-large linear energy input
welding high-strength steel and a production method thereof, and solves the problems of high alloying cost, poor
welding performance of
steel plates and low HAZ
impact toughness of the conventional large linear energy input
welding high-strength steel. The steel comprises the following chemical compositions in percentage by weight: 0.02 to 0.18 percent of C, 0.10 to 0.60 percent of Si, 0.60 to 1.90 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.010 percent of S, less than or equal to 0.060 percent of Nb, 0.0020 to 0.0060 percent of N, 0.0020 to 0.0060 percent of O, and at least two of 0.005 to 0.030 percent of Ti, less than or equal to 0.010 percent of Ca, less than or equal to 0.010 percent of Mg, 0.0003 to 0.003 percent of B, and 0.008 to 0.015 percent of Ce, and the balance of Fe and inevitable impurities. In addition, the chemical compositions meet the following conditions: (1) 4.0C+Mn is less than or equal to 2.1; (2) the carbon equivalent CE is equal to C+Si / 24+Mn / 6+Ni / 40+Cr / 5+Mo / 4+V / 14 and is less than or equal to 0.39. A
casting blank with the compositions is prepared through hot
metal desulphurization, converter top and bottom blowing, vacuum deep treatment and fine adjustment of the compositions, the
casting blank subjected to controlled rolling is air-cooled to
room temperature, and the high-strength strong-
toughness and excellent-match steel is obtained. The steel has the advantages of high strength, excellent low temperature
toughness, and high Z-direction performance, and can bear ultra-large linear energy input (more than or equal to 500kJ / cm) welding.