Hot galvanized high-strength steel plate with high surface quality and excellent corrosion resistance and manufacturing method thereof

Abstract

The invention discloses a hot galvanized high-strength steel plate with high surface quality and excellent corrosion resistance and a manufacturing method thereof. The hot galvanized high-strength steel plate sequentially comprises a substrate, a pre-metallization layer and Fe-Al barrier layer and a galvanized layer from bottom to top, wherein the chemical composition of the substrate comprises the following chemical components of, in percentage by weight, 0.15 wt% to 0.25wt% of C, 1.00 wt% to 2.00 wt% of Si, 1.50 wt% to 3.00 wt% of Mn, less than or equal to 0. 015 wt% of P, less than or equalto 0.012 wt% of S, 0.03 wt% to 0.06 wt% of Al and the balance Fe and inevitable impurities, and the pre-metallization layer is a metal Ni layer. The hot galvanized high-strength steel plate is good in surface quality, uniform and complete in plating layer, and better in corrosion resistance compared with a conventional hot galvanized product; and the yield strength of the hot galvanized steel plate is 600-900 MPa, the tensile strength is 980 MPa or above, the elongation is 15-22%, the surface quality and corrosion resistance are superior to those of conventional hot galvanized high-strength steel, and the hot galvanized teel plate is suitable for automobile structural parts and outer plates with higher requirements on surface quality, corrosion resistance and formability.

Description

technical field [0001] The invention relates to the technical field of hot-dip galvanized steel sheets, in particular to a hot-dip galvanized high-strength steel sheet with high surface quality and excellent corrosion resistance and a manufacturing method thereof. Background technique [0002] At present, the demand for lightweight automobiles is becoming stronger and stronger, coupled with the competitive pressure of aluminum, magnesium, plastics and other materials, forcing the development of automobile steel in the direction of high strength and high toughness. In order to improve the strength and toughness of the substrate, alloy elements such as Si, Mn, Cr, and Al are often added to the substrate. In recent years, a new generation of high-strength steel products with higher strength and better toughness represented by QP steel, TRIP steel and TWIP steel It has been continuously developed, and the Mn content in TWIP steel is even as high as 20wt.%. The existence of allo...

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Problems solved by technology

By optimizing the process and dew point atmosphere of the heating section and heat preservation section, the surface quality of the steel plate is improved, the platability is improved, and the hot-dip galvanized product is obtained, but the actual surface quality of the hot-dip galvanized product will fluctuate, which is greatly affected by the microscopic changes in the surface state of the incoming material , often produce missing plating, pitting, color difference and other problems

[0004] Chinese patent CN105112914A discloses a device and method for hot-dip galvanizing after PVD vacuum nickel plating, which does not involve specific product performance and does not know the effect of vacuum nickel plating

[0005] Chinese patent 201480008243.8 discloses a coated steel substrate for hot dip galvanizing containing 0.01-1% C, 0.15-15% Mn, 0.005-3.5% Si, 0.01-2% Al, 0.01- 2% Cr, two layers of pre-plating treatment are carried out before hot-dip galvanizing, the first pre-plating layer is mainly composed of Cu, and the second pre-plating layer is mainly composed of Fe; Matching, it is difficult to realize two layers of pre-galvanizing and hot-dip galvanizing in the same unit at the same time, so the actual product production is more difficult

[0006] Chinese patent CN101225518A discloses a method of hot-dip galvanizing after electroless nickel plating on silicon-containing steel. Production makes little sense

[0007] Chinese patent CN101160416B discloses a hot-dip galvanizing method without missing plating defects, which is mainly aimed at substrates with a Si content below 0.2%, does not involve other alloying elements such as Mn and Al, and has low strength and toughness of the steel plate, mainly improving The problem is missing plating, not related to other product performance

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