The invention discloses ultra-low temperature steel in great heat input
welding and a manufacturing method of the steel. The steel disclosed by the invention comprises the following components in percent by weight: 0.040-0.090% of C, less than or equal to 0.15% of Si, 1.10-1.50% of Mn, less than or equal to 0.013% of P, less than or equal to 0.0020% of S, 0.10-0.30% of Cu, 0.05-0.20% of Ni, 0.008-0.020% of Nb, less than or equal to 0.010% of Als, 0.008-0.013% of Ti, 0.0035-0.0065% of N, 0.001-0.004% of Ca, 0.0008-0.0020% of B and the balance of Fe and inevitable impurities. By adopting the simple combined design of
alloy elements in the steel disclosed by the invention, the TMCP (
Thermal Mechanical Control
Processing) technology is optimized without the requirement of adding a great number of noble elements such as Ni and Cu, the excellent patent steel plate low-temperature tenacity is acquired and simultaneously the low-temperature tenacity of the HAZ (
Heat Affected Zone) during large line energy
welding is also excellent; and the uniform and excellent
mechanical property, good
welding property and marine
atmosphere corrosion resistance are acquired, so that the steel disclosed by the invention is specially applicable to wind
tower structures on the sea, low-temperature pressure vessels, ocean platforms and bridges.