Hot-dip galvanized steel sheet with yield strength of 550MPa and production method thereof

Abstract

The invention discloses a hot-dip galvanized steel sheet with yield strength of 550MPa and a production method thereof, and belongs to the technical field of metal materials. The hot-dip galvanized steel sheet comprises the following chemical components in percentage by weight: 0.006% to 0.010% of C; less than or equal to 0.01% of Si; 0.10 to 0.30% of Mn; less than or equal to 0.015% of P; less than or equal to 0.040% of S; 0.005% to 0.070% of Als; 0.001% to 0.080% of Ti; 0.001% to 0.060% of Nb; less than or equal to 0.0030% of N; less than or equal to 0.0020% of O; 0.030 to 0.060% of Cu; 0.010 to 0.040% of Cr; and the reset is iron and other impurities. By controlling the content of C element in the steel sheet, adding Mn, Cr, Al, Cu and other elements, and controlling the contents of theadded elements, the strength of steel is improved. Ti and Nb are also added to the steel and the contents of the two elements satisfy the equation that Ti+Nb is greater than or equal to 0.050% but less than or equal to 0.120%. The two elements can not only increase the strength, but also make the toughness better, which is the most economical and most effective method to improve the performance of the steel. Through the compounding of the two elements, the ferrite grain size can be further refined, and the strength and toughness of the steel sheet can be improved at the same time, so that thestrength and toughness of the steel can be well matched, and the requirements of yield strength and elongation are satisfied at the same time.

Description

technical field [0001] The invention relates to the technical field of metal materials, in particular to a hot-dip galvanized steel sheet with a yield strength of 550 MPa and a production method thereof. Background technique [0002] Galvanized steel sheet is a welded steel sheet with a hot-dip galvanized or electro-galvanized layer on the surface. It is generally widely used in construction, home appliances, vehicles and ships, container manufacturing, and electromechanical industries. According to the production and processing methods, it can be divided into the following categories: (1) Hot-dip galvanized steel sheet, the thin steel sheet is immersed in a molten zinc tank to make a thin steel sheet with a layer of zinc on its surface. (2) Alloyed galvanized steel sheet is also manufactured by hot-dip method. After leaving the tank, it is immediately heated to about 500°C to form an alloy film of zinc and iron. (3) Galvanized steel plate. (4) Single-sided and double-side...

AI Technical Summary

Problems solved by technology

[0008] In view of the fact that the existing hot-dip galvanized steel sheets cannot meet the requirements of high strength and elongation at the same time, and cannot adapt to the use requirements of high strength and high toughness; at the same time, the existing production methods will cause large fluctuations in the strength of galvanized steel sheets, resulting in product output In order to solve the problem of instability, the present invention provides a hot-dip galvanized steel sheet with a yield strength of 550MPa and its production method. By controlling the C element content in the steel sheet and adding elements such as Mn, Ti, Nb, and Cu to strengthen the steel sheet, the P, S and other elements that are unfavorable to toughness, reduce Si and other elements that are unfavorable to surface quality, and cooperate with reasonable steelmaking, hot rolling, cold rolling and hot-dip galvanizing processes, so that hot-dip galvanized steel sheets have both high strength and high hardness. High elongation and high plastic strain ratio, and high surface quality requirements; and through the control of the process, the strength of the produced steel plate will not fluctuate greatly, which improves the product output rate and reduces the cost

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