Precoating steel plate for building structure and production method thereof

Abstract

The invention relates to a precoating steel plate for a building structure and a production method thereof. The precoating steel plate comprises the following components in percentage by weight: 0.14-0.20% of C, 0.06-0.20% of Si, 0.50-0.90% of Mn, less than or equal to 0.02% of P, less than or equal to 0.012% of S, 0.02-0.08% of solAl, less than or equal to 0.005% of N, less than 0.005% of Ti, less than 0.005% of Nb and the balance of Fe and inevitable impurities. The production method comprises the following steps: desulfurizing molten iron, smelting in a converter, carrying out continuous casting so as to form a blank and carrying out hot rolling and acid washing; carrying out cold rolling with five racks; annealing; carrying out hot-dip galvanizing; performing hydrocooling; finishing; carrying out tension leveling; washing with alkaline water; carrying out roller painting pretreatment on the surface of the steel plate; carrying out primary baking; carrying out conventional priming coat; carrying out secondary baking; carrying out conventional top coat; carrying out ternary baking and cooling; coiling; and packaging for later use. The precoating steel plate has the excellent coating adhesion and good corrosion resistance, and the cost is reduced by 10-15% as compared with the general precoating plate for the sibling structure, thereby improving market competitiveness.

Description

technical field [0001] The invention relates to steel plates for building structures and a production method, in particular to pre-coated steel plates for building structures and a production method. Background technique [0002] my country's pre-coated steel plates are mainly used in the construction field, and the proportion of sandwich panels and corrugated plates accounts for about 85% of the pre-coated steel plates used in construction, and pre-coated steel plates are required to have high strength, good toughness and corrosion resistance. Good sex. Many domestic users (especially those in the construction industry) need high-strength pre-coated steel plates to improve the strength of structural parts, reduce weight and reduce costs. [0003] Through domestic and foreign literature retrieval, the patent document "A Cold-based High-strength Galvanized Sheet and Production Method" with the Chinese Patent Publication No. CN101956126A was retrieved, and its chemical composi...

AI Technical Summary

Problems solved by technology

Its shortcomings are: the yield strength and tensile strength are too high, and the elongation is too low, that is, the highest is 24%, so it cannot be used as a pre-coated substrate for structure

What this patent document discloses is a kind of ultra-low-carbon hot-dip high-strength steel plate. Due to the addition of expensive alloys such as Ti and Nb, the production cost is high. Power is poor, and it is difficult to popularize and apply

[0004] With the development of pre-coated steel sheet technology, people are beginning to consider applying economical structural galvanized sheets as substrates to pre-coated steel sheets, but there are still some technical problems: For the high strength of the steel, more alloying elements are usually added to the steel, but after adding more alloying elements to the steel, on the one hand, the production cost of the pre-coated steel plate for the structure is increased, on the other hand, in the high-strength Among the alloying elements added to pre-coated steel (such as Mn, Si, Al, Cr, P, Ti, Nb, Mo, etc.), some elements (such as Mn, Si, Ti, Nb, Al, etc.) During the previous cold rolling recrystallization annealing process, it is easy to enrich on the surface and form a thin oxide film, thereby reducing the adhesion of the galvanized layer and resulting in a decrease in the corrosion resistance of the pre-coated sheet