High-strength hot-rolled plated steel sheet and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-2016199892-A1
Application number	US-201414914579-A
Country	US
Kind code	A1
Filing date	Jan 29, 2014
Priority date	Aug 30, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

Disclosed is a high-strength hot-rolled plated steel sheet capable of suppressing material deterioration at the time of plating, while having high strength, and a method for manufacturing the same. The high-strength hot-rolled plated steel sheet may include: a hot-rolled steel sheet base material composed of 0.03-0.1 wt % of C, below 0.06 wt % of Si, 0.7-2.0 wt % of Mn, below 0.02 wt % of P, below 0.01 wt % of S, 0.1-0.5 wt % of one or more precipitate forming elements, 0.3-1.0 wt % of Al, 0.1-0.5 wt % of Mo, Fe, and unavoidable impurities; and a plated layer formed on the surface of the hot-rolled steel sheet base material.

First claim

1 . A method for manufacturing a high-strength hot-rolled plated steel sheet, comprising:
(a) reheating a slab composed of 0.03-0.1 wt % of carbon (C), below 0.06 wt % of silicon (Si), 0.7-2.0 wt % of manganese (Mn), below 0.02 wt % of phosphorous (P), below 0.01 wt % of sulfur (S), 0.1-0.5 wt % of one or more precipitate forming elements, 0.3-1.0 wt % of aluminum (Al), 0.1-0.5 wt % of molybdenum (Mo), steel (Fe), and unavoidable impurities, the precipitate forming elements forming a precipitate at 500 to 900° C; (b) hot-rolling the slab; (c) cooling the hot-rolled slab, and then winding the cooled slab; and (d) plating the wound slab.

2 . The method of claim 1 , further comprising the step of alloying the slab having the plated layer formed thereon.

3 . The method of claim 1 , wherein the step of hot rolling the slab comprises:
roughing rolling the reheated slab at 950 to 1,050° C.; and finishing rolling the roughing-rolled slab at a finishing temperature condition of 800 to 900° C.

4 . The method of claim 1 , wherein the step of cooling the hot-rolled slab, and the winding the cooled slab comprises cooling the hot-rolled slab at an average cooling speed of 100° C./sec or more, and then winding the cooled slab at 580 to 660° C.

5 . The method of claim 1 , wherein the step of plating the wound slab comprises uncoiling and pickling the wound slab, and hot-dip plating the slab without a heat treatment at a temperature of Ac1 or more.

6 . The method of claim 1 , wherein the precipitate forming element comprises at least one of 0.03-0.1 wt % of niobium (Nb), 0.03-0.1 wt % of titanium (Ti), and 0.08-0.3 wt % of vanadium (V).

7 . The method of claim 1 , wherein the precipitate forming element comprises 0.03-0.1 wt % of Nb, 0.03-0.1 wt % of Ti, and 0.08-0.3 wt % of V.

8 . A high-strength hot-rolled plated steel sheet comprising:
a hot-rolled steel sheet base material composed of 0.03-0.1 wt % of C, below 0.06 wt % of Si, 0.7-2.0 wt % of Mn, below 0.02 wt % of P, below 0.01 wt % of S, 0.1-0.5 wt % of one or more precipitate forming elements, 0.3-1.0 wt % of Al, 0.1-0.5 wt % of Mo, Fe, and unavoidable impurities, the precipitate forming elements forming a precipitate at 500 to 900° C.; and a plated layer formed on the surface of the hot-rolled steel sheet base material, wherein the high-strength hot-rolled plated steel sheet exhibits a tensile strength of 780 to 900 MPa, a yield strength of 700 to 850 MPa, an elongation of 14 to 22%, and a hole expansion of 55% or more.

9 . The high-strength hot-rolled plated steel sheet of claim 8 , wherein the hot-rolled steel sheet base material of the hot-rolled plated steel sheet has a microstructure which is composed of a ferrite single-phase structure and in which fine precipitates having a size of less than 10 nm are formed.

10 . The high-strength hot-rolled plated steel sheet of claim 8 , wherein the precipitate forming element comprises at least one of 0.03-0.1 wt % of Nb, 0.03-0.1 wt % of Ti, and 0.08-0.3 wt % of V.

11 . The high-strength hot-rolled plated steel sheet of claim 8 , wherein the precipitate forming element comprises 0.03-0.1 wt % of Nb, 0.03-0.1 wt % of Ti, and 0.08-0.3 wt % of V.

Assignees

• Hyundai Steel Co

Inventors

• Ko Kang-Hee
• Do Hyeong-Hyeop

Classifications

• C21D8/0226 Primary

  Hot rolling · CPC title

• C21D9/46 Primary

  for sheet metals · CPC title

• C22C38/04

  containing manganese · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C21D2251/02

  Clad material · CPC title