High-strength hot-dip zinc-coated steel sheet

A hot-dip galvanized steel sheet, high-strength technology, applied in the direction of hot-dip galvanizing process, process efficiency improvement, transportation and packaging, etc., can solve the problem of reduced formability and other problems, and achieve excellent formability, light weight and anti-rust Favorable, good effect on the appearance of the plated surface

Active Publication Date: 2010-02-10
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the increase in the strength of the steel plate will lead to a decrease in the formability, the development of a material that has both high strength and high formability is expected

Method used

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  • High-strength hot-dip zinc-coated steel sheet
  • High-strength hot-dip zinc-coated steel sheet
  • High-strength hot-dip zinc-coated steel sheet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0130] Cast slabs obtained by melting steels having the chemical compositions shown in Table 1 were hot-rolled, pickled, and then cold-rolled to form cold-rolled steel sheets with a thickness of 1.2 mm. Then, in a continuous hot-dip galvanizing line with a DFF furnace (Direct Fired Furnace), the air ratio in the DFF furnace is controlled to 1.0 to 1.2 on the upstream side and 0.9 on the downstream side. Change the temperature on the output side of the DFF furnace, heat it up, heat treatment in the austenite single-phase region or two-phase region, and then use a galvanizing bath at 463°C to implement a coating amount of about 40-60g / m on each side 2 Plating, and alloying treatment, so that the Fe% of the plating layer as the target condition becomes about 10% by mass. When adjusting the degree of alloying, the passing speed and alloying temperature should be changed appropriately. 0.3% temper rolling was performed on the obtained steel sheet.

[0131]

[0132] Here, 10 fi...

Embodiment 2

[0146] Steel slabs obtained by melting steels having the composition of steels C, E, and H shown in Table 1 were hot-rolled, then pickled, and then cold-rolled to form cold-rolled steel sheets with a thickness of 1.2 mm. Then, on a continuous hot-dip galvanizing production line with a DFF furnace (Direct Fired Furnace), continuous annealing was carried out according to the annealing conditions (DFF furnace output side temperature, annealing temperature, cooling stop temperature) shown in Table 3, Then use a galvanizing bath at 463°C to apply a coating amount of about 40-60g / m on one side 2 Plating and alloying treatment of the coating. 0.3% temper rolling was performed on the obtained steel sheet. In addition, the air ratio in the DFF furnace in the heating stage was controlled to be 1.0 to 1.2 on the upstream side and 0.9 on the downstream side.

[0147] For the hot-dip galvanized steel sheets thus obtained, the microstructure, hardness, and mechanical property values ​​(te...

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Abstract

The invention provides a high-strength hot-dip zinc-coated steel sheet which has a tensile strength of 590MPa grade, excellent surface appearance of coating, and excellent formability. A hot-dip zinc-coated steel sheet obtained by forming a hot-dip zinc coating layer on the surface of a steel sheet, which has a composition containing by mass C: 0.005 to 0.12%, Si: 0.7 to 2.7%, Mn: 0.5 to 2.8%, P:0.1% or below, S: 0.07% or below, Al: 1.0% or below and N: 0.008% or below with the balance consisting of Fe and unavoidable impurities and a structure comprising at least 90% of ferrite and 2 to 10%of martensite in terms of area ratio and in which the average Vickers hardness of the ferrite is 120 or above and the ratio of the length of grain boundaries with precipitated inclusions to the wholelength of grain boundaries is 50% or below in the surface region of substrate iron spread at a depth of 3¢mu!m from the interface between the coating layer and the substrate iron on the substrate ironside.

Description

technical field [0001] The present invention relates to a high-strength hot-dip galvanized steel sheet that is excellent in formability and has a good plating surface appearance, which is used in the fields of the automobile industry and the electric industry. In the present invention, the hot-dip galvanized steel sheet and the alloyed galvanized steel sheet obtained by alloying the plating layer are collectively referred to as a hot-dip galvanized steel sheet. Background technique [0002] In recent years, from the viewpoint of global environmental protection, for example, the improvement of the fuel consumption of automobiles has become an important issue. Therefore, there is a significant trend towards reducing the weight of the vehicle body itself by reducing the thickness of the vehicle body itself by increasing the strength of the vehicle body material. However, since the increase in the strength of the steel sheet leads to a decrease in the formability, the developme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/60C23C2/06C23C2/28
CPCC22C38/002C22C38/06C23C2/28C22C38/02B32B15/013C22C38/04C23C2/06C22C38/001Y10T428/12972Y10T428/12951Y10T428/12799C22C38/60
Inventor 金子真次郎松田广志川崎由康中垣内达也铃木善继伏胁祐介河野崇史松冈才二
Owner JFE STEEL CORP
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