Ultrathin specification high strength steel plate used under condition of -60 DEG C and manufacturing method thereof

Abstract

The invention discloses an ultrathin specification high strength steel plate used under the condition of -60 DEG C and a manufacturing method thereof. The steel plate comprises chemical components including, by mass percent, not larger than 0.05% of C, 0.20 to 0.40% of Si, not larger than 1.0% of Mn, not larger than 0.15% of the sum of Nb+Ti+V, not larger than 0.30% of Cr, not larger than 0.008% of P, not larger than 0.0008% of S, not larger than 0.002% of N, not larger than 0.0010% of O, not larger than 0.0001% of H, not larger than 100 ppm of the sum of P+S+[N]+[O]+[H], not larger than 0.30%of Ni, not larger than 0.30% of Cu, not larger than 0.30% of Mo and the balance Fe and inevitable impurities. The structure of the steel plate is uniform quasi-polygon ferrite, the thickness ranges from 4 mm to 8 mm, the yield strength ranges from 460 MPa to 560 MPa, the tensile strength ranges from 550 MPa to 630 MPa, and the -60 DEG C impact power is larger than or equal to 200 J. The manufacturing method comprises the process flows of KR molten iron pre-treatment, converter operation, LF, RH vacuum degassing, slab continuous casting, slow cooling, rolling and cooling. The production blankof a high-strength, low-temperature and high-toughness ultrathin steel plate can be filled up.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and relates to an ultra-thin high-strength steel plate capable of being used in a -60°C environment and a manufacturing method thereof. Background technique [0002] With the need for lightweight engineering equipment, more and more low-alloy structural steel plates will be replaced by thin-gauge high-strength steel plates. However, in the manufacturing process of medium and heavy plates, extreme specifications are often the most technically difficult and demanding. At present, there are many studies on extra-thick high-strength steel plates, but for ultra-thin high-strength steel plates and their manufacturing methods, what has been reported There are few reports on ultra-thin high-strength steel plates that can meet the conditions of -60°C. [0003] In the industrial production process, the production of ultra-thin steel plates is very difficult, mainly in two aspects. One is that the compre...

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Problems solved by technology

However, in the manufacturing process of medium and heavy plates, extreme specifications are often the most technically difficult and demanding. At present, there are many studies on extra-thick high-strength steel plates, but for ultra-thin high-strength steel plates and their manufacturing methods, what has been reported There are few, and there are no reports on ultra-thin high-strength steel plates that can be used under the condition of -60 °C

[0003] In the industrial production process, the production of ultra-thin steel plates is very difficult, mainly in two aspects. One is that the compression ratio is too large (usually the compression ratio is 20-50 times), resulting in Concentrated segregation bands and dense distribution of inclusions in the finished steel plate , resulting in very unstable low-temperature impact energy, especially the impact energy of the 5mm-thick impact specimen is low, which cannot be used under the condition of -60°C; The reduction is too fast, and the production cannot be carried out according to the normal controlled rolling process. The rolling of conventional medium and heavy plate mills is extremely difficult, and the controlled rolling cannot be realized.

Under the combined effect of the two aspects, the low-temperature impact toughness of ultra-thin high-strength steel plates is unstable, and the strength is difficult to control. Therefore, there is no report on the production of ultra-thin high-strength steel plates with good low-temperature toughness by TMCP process

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