780MPa-grade forming-enhanced hot-dip galvanized dual-phase steel and manufacturing method thereof

A dual-phase steel and hot-dip galvanizing technology, which is applied in the hot-dip galvanizing process, coating, metal material coating process, etc., can solve the problems of fine-grain strengthening of the steel plate matrix, high phosphorus removal equipment, and surface color difference defects of galvanized products and other problems, to achieve the effect of high plastic hole expansion performance and high hole expansion performance

CN114525448APending Publication Date: 2022-05-24HANDAN IRON & STEEL GROUP +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2022-05-24

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Abstract

The invention provides 780MPa-grade forming-enhanced hot-dip galvanized dual-phase steel and a preparation method thereof. The dual-phase steel comprises the following chemical components in percentage by mass: 0.14%-0.18% of C, 0.15%-0.30% of Si, 2.0%-2.3% of Mn, 0.5%-0.7% of Al, less than or equal to 0.015% of P, 0.02%-0.03% of Nb, 0.015%-0.025% of Ti, 0.1%-0.4% of Cr, 0.007%-0.0015% of B and the balance of Fe and inevitable impurity elements. The production method comprises the procedures of converter smelting, hot rolling, acid pickling and cold rolling, annealing and hot galvanizing, in the hot rolling procedure, the slab heating temperature is controlled to be 1180-1210 DEG C, the heating time is 180-220 min, and the hot rolling coiling temperature is 500-550 DEG C. The dual-phase steel provided by the invention has relatively high surface quality.
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Description

technical field

[0001] The invention belongs to the field of manufacturing high-strength steel for automobiles, and relates to a 780MPa-level enhanced formability hot-dip galvanized dual-phase steel and a manufacturing method thereof. Background technique

[0002] As customers have higher and higher requirements for the formability of hot-dip galvanized dual-phase steel, enhanced formability hot-dip galvanized dual-phase steel is more and more favored by customers.

[0003] However, the current enhanced formability dual-phase steel meets the high performance, and the surface quality problem is gradually paid attention by customers. Due to the large number of alloying elements in steel, especially Si and Mn elements, surface quality problems such as missing plating and pitting are prone to occur during the coating process, which in turn affects the quality of the finished product.

[0004] The patent application with publication number CN 111893379 A discloses a 780MPa grade...

Examples

Embodiment 1

[0054] The metallographic structure of the high-surface dual-phase steel prepared in Example 1 is shown in figure 1 , Determination of retained austenite content by electron backscatter diffraction (EBSD) Metallographic diagram, see figure 2 , the content of retained austenite in the structure can be calculated to be about 6% to 8% using statistical software. The surface of the finished product in Example 1 is as follows: image 3 As shown, it can be seen that the surface quality is good, and there is no color difference, landscape painting, and selective oxidative leakage plating defects.