Steel sheet excellent in bake hardenability and corrosion resistance and method for producing the same

Abstract

The present invention relates to a steel sheet used as a material for automobile outer panels, etc., and a manufacturing method thereof, and more particularly, to a cold-rolled steel sheet having excellent bake hardenability, corrosion resistance, and aging resistance, and a hot-dipped steel sheet Zinc-based steel sheet and its manufacturing method.

Description

technical field

[0001] The present invention relates to a steel sheet used as a material for automobile outer panels, etc., and a manufacturing method thereof, and more particularly, to a cold-rolled steel sheet having excellent bake hardenability, corrosion resistance, and aging resistance, and a hot-dipped steel sheet Zinc-based steel sheet and its manufacturing method. Background technique

[0002] With the regulation of strengthening the collision stability of automobiles and fuel efficiency, high-strength steel is being actively used to meet both the weight reduction and high-strength of the car body, and according to this trend, the application of high-strength steel to the outer panels of automobiles is also expanding.

[0003] At present, most of them use 340MPa-class bake-hardened steel as the outer panels of automobiles, but some use 490MPa-class steel plates, and it is expected to expand to 590MPa-class steel plates in the future.

[0004] As described above, wh...

Examples

Embodiment Construction

[0150] A billet having an alloy composition described in Table 1 below was prepared, and then a hot-dip galvanized steel sheet (GI steel sheet) or an alloyed hot-dip galvanized steel sheet (GA steel sheet) was manufactured using the manufacturing process described in Table 2 and Table 3 below. At this time, the hot-dip galvanizing is performed using a conventional hot-dip galvanizing bath, and the alloying heat treatment is also performed under normal conditions (500-540° C.).

[0151] For reference, in Table 1 below, Invention Steels 1, 2, 4, and 5 and Comparative Steels 1 and 2 correspond to alloyed hot-dip galvanized steel sheets, and Invention Steels 3, 6, and 7 correspond to hot-dip galvanized steel sheets. Comparative steel 1 is BH steel using conventional ultra-low carbon steel, and Comparative steel 2 is high carbon DP steel series steel.

[0152] The microstructures of the respective plated steel sheets manufactured as described above were observed and their physical ...

technical field

[0001] The present invention relates to a steel sheet used as a material for automobile outer panels, etc., and a manufacturing method thereof, and more particularly, to a cold-rolled steel sheet having excellent bake hardenability, corrosion resistance, and aging resistance, and a hot-dipped steel sheet Zinc-based steel sheet and its manufacturing method. Background technique

[0002] With the regulation of strengthening the collision stability of automobiles and fuel efficiency, high-strength steel is being actively used to meet both the weight reduction and high-strength of the car body, and according to this trend, the application of high-strength steel to the outer panels of automobiles is also expanding.

[0003] At present, most of them use 340MPa-class bake-hardened steel as the outer panels of automobiles, but some use 490MPa-class steel plates, and it is expected to expand to 590MPa-class steel plates in the future.

[0004] As described above, wh...

Examples

Embodiment Construction

[0150] A billet having an alloy composition described in Table 1 below was prepared, and then a hot-dip galvanized steel sheet (GI steel sheet) or an alloyed hot-dip galvanized steel sheet (GA steel sheet) was manufactured using the manufacturing process described in Table 2 and Table 3 below. At this time, the hot-dip galvanizing is performed using a conventional hot-dip galvanizing bath, and the alloying heat treatment is also performed under normal conditions (500-540° C.).

[0151] For reference, in Table 1 below, Invention Steels 1, 2, 4, and 5 and Comparative Steels 1 and 2 correspond to alloyed hot-dip galvanized steel sheets, and Invention Steels 3, 6, and 7 correspond to hot-dip galvanized steel sheets. Comparative steel 1 is BH steel using conventional ultra-low carbon steel, and Comparative steel 2 is high carbon DP steel series steel.

[0152] The microstructures of the respective plated steel sheets manufactured as described above were observed and their physical ...

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