Ultra-large linear energy input welding high-strength steel and production method thereof

Abstract

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.

Description

technical field [0001] The invention relates to a low-carbon low-alloy high-strength steel, in particular to a super-large heat input welding high-strength steel and a production method thereof Background technique [0002] With the development of the national economy and the acceleration of national infrastructure construction, steel structures in various fields are becoming larger and larger. In order to further improve welding efficiency, greatly reduce the labor intensity and production costs of steel structure welding, the strength of steel plates for making large steel structures The requirements for toughness and welding line energy that the steel plate can withstand are gradually increasing. Therefore, technicians have made various improvements to the composition and production methods of the steel plate in order to achieve better performance, but there are still various deficiencies. [0003] Such as Japanese patent JP20070158284 (NIPPON STEEL CORP. HIGH TENSILSTREN...

AI Technical Summary

Problems solved by technology

The disadvantage is that the welding heat input that the steel plate can withstand is only 100kJ / cm, which is still difficult to meet the industrial requirements for the ultra-large heat input welding performance of high-strength steel

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