Super-thick steel plate for construction with excellent Z-directional performance and production method thereof

Abstract

The invention relates to a super-thick steel plate for construction with an excellent Z-directional performance, which is characterized in that the chemical composition (by weight percentage) of steel is as follows: C accounts for 0.10-0.22 percent, Si accounts for 0.10-0.50 percent, Mn accounts for 1.0-2.0 percent, P accounts for less than or equal to 0.025 percent, S accounts for less than or equal to 0.006 percent, Nb accounts for 0.01-0.06 percent, V accounts for 0.02-0.11 percent, Ti accounts for 0.005-0.025 percent, Ca accounts for 0.0004-0.0040 percent, Alt accounts for 0.01-0.05 percent, H accounts for less than or equal to 0.0002 percent, and the rest is Fe and inevitable impurities. The thickness of the steel is more than or equal to 60mm. The production of the super-thick steel plate comprises the following steps: deep desulphurization of molten iron, combined blowing on the top and bottom of a converter, refining outside the converter, die casting, blooming, reheating of a cogged ingot, free rolling, air cooling and normalizing; wherein the cogged ingot is reheated to be 1100-1250 DEG C; and the steel plate is heated to be 860-920 DEG C for normalizing. The super-thick steel plate has an excellent Z-directional performance, and can be widely applied in the constructional engineering field such as high-rise buildings, large-span stadiums and the like.

Description

technical field [0001] The invention relates to a steel plate for construction and a manufacturing method thereof, in particular to an extra-thick steel plate for construction with excellent Z-direction performance and a manufacturing method thereof. Background technique [0002] In recent years, with the development of large-scale and complex buildings, the demand for extra-thick plates (≥60mm) is increasing, and the requirements for its internal quality are becoming increasingly stringent. In the construction of some high-rise buildings and long-span venues, it is generally required that the steel plate has good lamellar tear resistance. At present, the reduction of area ψz in the thickness direction is widely used in the world as the main index to measure the Z-direction performance and evaluate the lamellar tear sensitivity of the steel plate. Lamellar tearing is a very harmful form of failure. Simply put, its formation mechanism is that under the action of welding stre...

AI Technical Summary

Problems solved by technology

Its shortcoming is that alloying elements such as Cu and Ni are added to the composition design of the steel plate adopting normalizing treatment. Since the price of Ni is relatively expensive, the cost of the steel plate is greatly increased.

The shortcoming of the technology in this document is that the H content is very strict in the composition design, requiring H ≤ 0.8ppm. At present, the H content that domestic steel mills can control is at least 1ppm, and H below 1ppm is not feasible for large-scale production operations.

In addition, the method of this comparative document cannot produce extra-thick steel plates, and the thickness of the steel plates is less than 35 mm, which does not belong to the category of extra-thick plates

And this document technology adopts controlled rolling (CR) process, and manufacturing efficiency is not high

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