High-strength low-alloy hot-dip aluminized and galvanized steel strip and production method thereof

Abstract

The invention relates to a high-strength low-alloy hot-dip aluminized and galvanized steel strip and a production method thereof. The hot-dip aluminized and galvanized steel strip comprises a steel base plate and an alloy coating, wherein the steel base plate comprises the following chemical components in percentage by weight: 0.02-0.10% of C, 0.5-1.2% of Mn, 0.01-0.07% of P, 0.01-0.12% of Nb, less than or equal to 0.0080% of N, less than or equal to 0.02% of S and the balance of Fe and inevitable impurities, wherein Nb-0.22C-1.1N is equal to or greater than 0.01% and less than or equal to 0.1% and Mn / 1.7S is equal to or greater than 8; the alloy coating comprises the following chemical components in percentage by weight: 50-58% of Al, 40-45% of Zn, 1.0-2.0% of Si, 0.005-0.020% of Ti and the balance of unavoidable impurities. According to the hot-dip aluminized and galvanized steel strip, by virtue of smelting, casting, carrying out hot rolling and cold rolling, continuously annealing and carrying out hot-dip aluminizing and galvanizing, the aluminum-zinc coating is evenly and densely adhered to the steel base plate, the obtained low-alloy hot-dip aluminized and galvanized steel strip has the yield strength of 410-570MPa, the tensile strength equal to or greater than 470MPa and elongation equal to or greater than 15% and has both good strength and toughness and excellent corrosion resistance. The production process is low in cost and high in steel plate yield.

Description

technical field [0001] The invention belongs to the field of coiled steel plate material production, and in particular relates to a high-strength low-alloy hot-dip aluminum-zinc steel strip and a production method thereof. Background technique [0002] Due to its low cost and good strength and toughness, high-strength low-alloy steel has attracted widespread attention and been applied all over the world. Generally, the C component in steel is ≤0.1%. By adding alloy elements such as Ti and Nb, carbonitrides are formed with atoms such as C and N in the matrix, and these carbonitrides are precipitated in a small amount in the matrix to hinder the movement of dislocations. Thereby obtaining higher steel plate strength. People can choose pure Ti, pure Nb or Ti, Nb composite composition design to achieve the expected performance goals, but in terms of cost economy and performance stability, the type and ratio of the alloy added are the key factors that determine the manufacturabi...

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Problems solved by technology

[0004] Chinese patent CN200310106261.3 discloses a hot-dip aluminum-zinc alloy steel plate and its manufacturing method. The method adopts ordinary cold-rolled substrates to produce aluminum-zinc-coated products. The yield strength is greater than 228MPa and the elongation is about 20%, but it cannot meet the requirements. Requirements for yield strength 410-570MPa

However, it cannot meet the requirements of yield strength 410-570MPa and elongation at break greater than 15%.

[0006] Chinese patent CN200710093976.8 discloses a hot-dip galvanized steel sheet / strip for deep drawing and its production method. The method uses IF steel substrates to produce galvanized products. The yield strength is 140-220MPa, and the tensile strength is 260-350MPa. The elongation is greater than 30%, but it cannot meet the requirement of yield strength of 410-570MPa

However, high-strength low-alloy hot-dip galvanized products with a yield strength of 410-570MPa, a tensile strength of not less than 470MPa, and an elongation of more than 15% are blank at home and abroad.

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