S420 high-strength low-temperature structural steel and normalizing rolling preparation method thereof

Abstract

The invention discloses S420 high-strength low-temperature structural steel and a normalizing rolling preparation method thereof, and relates to the technical field of steel production. The S420 high-strength low-temperature structural steel comprises the following chemical components in percentage by mass: 0.14%-0.16% of C, 1.25%-1.50% of Mn, 0.2%-0.3% of Si, 0.04%-0.05% of Nb, 0.06%-0.09% of V, 0.008%-0.015% of Ti, 0.25%-0.35% of Ni, 0.015%-0.040% of Alt, less than or equal to 0.1% of Cu, less than or equal to 0.02% of P, less than or equal to 0.005% of S, less than or equal to 0.006% of N, less than or equal to 0.30% of Cr, less than or equal to 0.10% of Mo and the balance of Fe and inevitable impurities. The high-strength low-temperature structural steel with the thickness of 60-80 mm is produced, structure performance of a thick steel plate is improved through reasonable component design and a rolling process, the yield strength is higher than 420 MPa, the tensile strength is 520-680 MPa, the ductility is larger than 19%, and the low-temperature impact energy at the temperature of -50 DEG C is higher than 50 J.

Description

technical field [0001] The invention relates to the technical field of iron and steel production, in particular to a S420 high-strength low-temperature structural steel and a normalizing rolling preparation method thereof. Background technique [0002] High-strength low-temperature structural steel is a resource-saving product with high technical content and high added value. Normalized hot-rolled structural steel plates are widely used in large-scale construction machinery, construction, offshore engineering platforms, UHV power transmission Components, vehicle frame structures, pressure vessels and other fields, especially in some welded structures, some components must be made of structural steel with excellent performance in the normalized state. The traditional normalizing process is to reheat the rolled steel plate to the normalizing temperature for a certain period of time and then air cool it, which not only increases the production cost and energy consumption, but a...

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Problems solved by technology

[0003] The Chinese patent application with the publication number CN103540848A discloses "A 420MPa normalized steel plate for extra-thick specification structure and its manufacturing method". , the cost of the alloy is high, and the Ceq is relatively high. At the same time, this method cannot get rid of the limitation of the compression ratio. The continuous casting slab with a thickness of 400mm can only produce products with a maximum thickness of 120mm.

[0004] The Chinese patent application with the publication number CN104018071A discloses a "production method of low-carbon equivalent high-toughness Q420E steel plate". This method adopts the traditional TMCP process to produce Q420E steel plate, which cannot get rid of the limitation of compression ratio, and is only suitable for the production of steel plate below 30mm , not suitable for the production of extra-thick steel plates

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