Ultra high strength ship plate steel and production method thereof

Abstract

The invention discloses ultra high strength ship plate steel and a production method thereof. A plate blank comprises the following components in percentage by weight: 0.02-0.09 percent of C, 0.1-0.4 percent of Si, 0.5-1.6 percent of Mn, 0.01-0.04 percent of Alt, 0.02-0.05 percent of Nb, 0.008-0.02 percent of Ti, 0.3-0.7 percent of Cr, 0.2-0.5 percent of Mo, 0.5-1 percent of Ni, 0.2-1 percent of Cu, less than 0.013 percent of P, less than 0.005 percent of S, less than 0.0012 percent of O, less than 0.0045 percent of N, less than 0.00015 percent of H and the balance of Fe and inevitable impurities. The production method comprises the following steps of heating the plate blank with the thickness of 220-300 mm before rolling at the temperature of 1250 DEG C; starting rough rolling at the starting temperature of not less than 1100 DEG C; starting finish rolling at the temperature of not more than 910 DEG C, and stopping finish rolling at the temperature of 870-890 DEG C; rolling a steel plate with the thickness of 10-60 mm; rapidly entering ACC to control cooling at the cooling speed of 8-12 DEG C/s after finish rolling; returning red at the temperature of 650-680 DEG C; and tempering for 90-180min at the temperature of 500-680 DEG C. The product has good comprehensive mechanical property.

Description

technical field [0001] The invention relates to a low-alloy high-strength steel, in particular to an ultra-high-strength ship plate steel and a production method thereof. Background technique [0002] The trend of large-scale and high-speed ships makes the steel for shipbuilding must have the characteristics of high strength, high toughness, thick gauge, seawater corrosion resistance, easy welding and good formability. The production of shipbuilding steel that meets (extra) thick specifications while ensuring strength, plasticity, good low-temperature toughness and weldability will provide strong technical support and power support for the rapid development of the shipbuilding industry. [0003] At present, controlled rolling and controlled cooling technology is widely used in the production of ship plate steel. Through reasonable design of alloy element content and controlled rolling and controlled cooling parameters, such as final rolling temperature, final cooling temper...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the problem of insufficient strength and toughness in the production of (extra) thick specification ultra-high-strength ship plate steel by adopting control and cooling technology, the purpose of this invention is to provide a kind of ultra-high-strength ship plate steel and its production method. The product produced by the present invention Not only good strength and toughness, but also good comprehensive performance

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