A high-strength and high-toughness hot-rolled weather-resistant steel plate and its preparation method

Abstract

The invention relates to a high-strength and high-toughness weather-proof hot-rolled steel plate comprising the chemical components in percentage by weight: (wt,%): 0.05%-0.10% of C, 0.10%-0.50% of Si, 1.00%-1.30% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, 0.30%-0.70% of Cr, 0.10%-0.40% of Ni, 0.25%-0.50% of Cu, 0.020%-0.050% of Al, 0.010%-0.040% of Nb, 0.010%-0.030% of Ti and the balance Fe and unavoidable impurity elements. Meanwhile, the traditional hot strip rolling process is adopted, and a preparation method specifically comprises the steps: deep desulphurization of molten iron until S is less than or equal to 0.0050%, converter top and bottom combined blowing, alloy fine adjustment, LF secondary refining, slab continuous casting, heating, two-rack rough rolling and seven-rack finish rolling, laminar cooling and reeling. The steel plate disclosed by the invention has the mechanical properties that ReL is 450-500MPa, the Rm is greater than or equal to 550MPa, A is 25.0%-30.0%, the -60 DEG C longitudinal Charpy V-shaped gap impact power is greater than 300J, the high-strength and high-toughness weather-proof hot-rolled steel plate has good matching of strength and toughness, good cold bending forming and welding properties and favorable atmosphere corrosion resistance, and the corrosion resistance of the high-strength and high-toughness weather-proof hot-rolled steel plate is twice as high as that of Q345B steel.

Description

technical field [0001] The invention relates to the field of weathering steel manufacturing, in particular to a high-strength and high-toughness hot-rolled weathering-resistant steel plate with excellent low-temperature toughness and ferrite+pearlite structure and a preparation method thereof Background technique [0002] Weather-resistant steel refers to low-alloy steel that has good corrosion resistance in the atmosphere by adding a small amount of alloying elements such as Cu, P, Cr, Ni, Mo, and Re. With the popularization and application of weathering steel to outdoor load-bearing structural parts such as construction machinery, bridges, buildings, and transmission towers, the complex working environment requires weathering steel not only to have good atmospheric corrosion resistance, but also to have high strength and stability. Low-temperature toughness, especially steel for construction machinery and bridges used at low temperatures in cold regions, requires impact pr...

AI Technical Summary

Problems solved by technology

Due to the low C content, a large amount of Mn and microalloying element Nb are added to improve the strength, and the production cost is high

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