Production method of deep-drawing zinc-iron alloy plated steel plate with ductility higher than 38% and with compact plating structure

Abstract

The invention discloses a production method of a deep-drawing zinc-iron alloy plated steel plate with a compact surface plating structure. The production method comprises the steps of molten iron desulphurization, converter smelting, alloying, continuous casting, heating, rolling and alloying continuous hot galvanizing. In the alloying continuous hot galvanizing process, after galvanizing and zinc pot delivery are carried out, the cooling speed of an upstream section is controlled to be higher than or equal to 40 DEG C/s, and the cooling speed is controlled to be higher than or equal to 30 DEG C/s after alloying. The deep-drawing zinc-iron alloy plated steel plate in which zinc-iron alloy plating surface grains are fine, distribution is even in size, the plating structure is compact (the area ratio of surface holes is smaller than or equal to 5%), and the surface is free of obvious microcracks is obtained on the premise that the mechanical performance of the steel plate is guaranteed. The anti-pulverization performance of the zinc-iron alloy plated steel plate is improved, the 60-degree V bending test grade reaches the first level, and the phenomena of pulverization and falling of a plating are not likely to happen in the steel plate punching molding process; and accordingly the purposes of quality and production of zinc-iron alloy plated steel plate workpieces are achieved.

Description

technical field [0001] The invention relates to a production technology of a coated steel plate, in particular to a production method of a deep-drawing zinc-iron alloy coated steel plate with an elongation rate higher than 38% and a dense coating structure. Background technique [0002] Zinc-iron alloy coated steel sheet (GA) has excellent corrosion resistance, paintability, weldability and anti-gravel performance, and is widely used in automobile panels. However, at present, the surface coating structure of the conventional deep-drawing GA board is loose and not dense, the surface structure of the coating is coarse, the grain size distribution is uneven, and there are obvious micro-cracks on the surface. The surface quality of stamped parts and production tools are adversely affected. [0003] There are some studies at home and abroad on how to improve the surface structure of galvanized steel sheets, such as: the device and accelerated cooling method provided by Ukraine t...

AI Technical Summary

Problems solved by technology

However, at present, the surface coating structure of the conventional deep-drawing GA board is loose and not dense, the surface structure of the coating is coarse, the grain size distribution is uneven, and there are obvious micro-cracks on the surface. Detrimental effects on stamped part surface quality and production tooling

[0003] There are some studies at home and abroad on how to improve the surface structure of galvanized steel sheets, such as: the device and accelerated cooling method provided by Ukraine that can ensure the rapid cooling of the circular section of the hot-rolled metal after final rolling; Research on the effect of rate on the microstructure and yield phenomenon of hot-dip galvanized dual-phase steel DP780; Maanshan Iron and Steel Co., Ltd.’s practice of adjusting and optimizing radiant tube heating equipment and rapid cooling equipment to ensure the quality of galvanized sheet products; A high-strength cold-rolled hot-dip galvanized dual-phase steel plate (CN102719751B) produced by the method of micro-slow cooling and two-time quick cooling in the fast cooling section; and a multi-stage composite cooling method for the upward section of the hot-dip galvanizing unit provided by Baosteel (CN102618812B) and a galvanized strip cooling device (CN201250279) comprising a post-plating quick cooling device and an initial cooling device, the aforementioned prior art is all about controlling the substrate structure and mechanical properties or hot-dip galvanizing by adjusting the cooling rate The quality of the pure zinc coating (such as spangles) on the steel plate (GI plate) to improve the quality of the steel plate has failed to solve the problem of easy peeling off and pulverization of the steel plate coating on the premise of ensuring the excellent mechanical properties of the steel plate

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