High-strength low-crack sensitive slab and manufacture method thereof

Abstract

The invention relates to a high-strength low-crack sensitive slab and a manufacture method thereof. The slab is prepared from the following chemical components in percentage by weight: 0.06-0.09 percent of C, 0.1-0.3 percent of Si, 1.35-1.55 percent of Mn, 0.02-0.04 percent of Nb, 0.02-0.04 percent of V, 0.01-0.02 percent of Ti, 0.15-0.25 percent of Ni, 0.1-0.2 percent of Cr, 0.15-0.25 percent of Cu, 0.02-0.04 percent of Al, not more than 0.006 percent of N, not more than 0.016 percent of P, less than 0.004 percent of S and the balance of Fe and impurities. The manufacture method of the high-strength low-crack sensitive slab comprises the following sequential steps of: heating a casting blank; descaling; controlling rolling; controlling cooling, straightening, and the like. The slab of the invention can reach the thickness of 80 mm, and the yield strength over 420 MPa and has excellent comprehensive mechanical performance, simple and convenient production process and low cost.

Description

technical field [0001] The invention relates to a high-strength structural steel and a preparation process thereof, in particular to a high-strength, low-crack-sensitivity thick plate with a thickness up to 80 mm and a yield strength of 420 MPa and a manufacturing method thereof. Background technique [0002] In recent years, buildings have been developing in the direction of super high-rise buildings and large spaces. For this reason, steel materials are required to have high strength and large cross-section characteristics. In this way, the requirements for mechanical performance, welding performance and thickness of steel are getting higher and higher. For example, the properties of steel plates used in high-rise buildings generally need to meet the following standards: yield strength ≥ 390MPa, yield ratio Performance (reduction of area) ≥ 15%, high low temperature (≤ 0 ℃) toughness, large thickness (≥ 40mm) and good welding performance (can withstand large welding heat i...

AI Technical Summary

Problems solved by technology

However, the carbon content of this steel is relatively high, and the weldability of the steel plate is adversely affected; another example, the invention patent with the patent publication number of CN101397625A records a kind of ultra-fine-grained steel plate with a yield strength of 420MPa and its manufacturing method. The weldability of the steel plate is Good, but it is only suitable for steel plates no thicker than 20mm, and it takes a long time to warm up in the middle, which affects the production rhythm

For another example, the invention patent with the patent publication number of CN101343685A discloses a heat treatment method for a high-strength steel plate with a yield strength of 420 MPa, but the steel plate has a high carbon content and requires normalizing treatment, resulting in high production process costs.

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