Acid-resistant steel sheet and manufacturing method therefor

Patent metadata

Field	Value
Publication number	US-2022042179-A1
Application number	US-201917297938-A
Country	US
Kind code	A1
Filing date	Nov 26, 2019
Priority date	Nov 30, 2018
Publication date	Feb 10, 2022
Grant date	—

Abstract

An acid-resistant steel sheet according to an embodiment of the present invention includes, by wt %, equal to or less than 0.1% of C (excluding 0%) and 2.0 to 4.0% of Si, and includes a remainder of Fe and inevitable impurities, and the content of Si of the surface portion by the inward depth of up to 10 μm from the surface of the steel sheet is equal to or greater than 15 wt %.

First claim

1 . An acid-resistant steel sheet comprising,
by wt %, equal to or less than 0.1% of C (excluding 0%) and 2.0 to 4.0% of Si, and a remainder of Fe and inevitable impurities, wherein the content of Si of the surface portion by the inward depth of up to 10 μm from the surface of the steel sheet is equal to or greater than 15 wt %.

2 . The acid-resistant steel sheet of claim 1 , further comprising
at least one of 0.1 to 0.5 wt % of Mn, equal to or less than 0.1 wt % of Al, equal to or less than 0.01 wt % of P, equal to or less than 0.01 wt % of S, and equal to or less than 0.01 wt % of N.

3 . The acid-resistant steel sheet of claim 1 , further comprising
equal to or less than 0.1 wt % of Cr, equal to or less than 0.1 wt % of Ni, equal to or less than 0.1 wt % of Cu, equal to or less than 0.1 wt % of Nb, and equal to or less than 0.1 wt % of Mo.

4 . The acid-resistant steel sheet of claim 1 , wherein
when soaked for an hour in a 1 wt % sulfuric acid solution at 70° C., an average corrosion rate is equal to or less than 3.5 mg/cm 2 ·h.

5 . The acid-resistant steel sheet of claim 1 , wherein
an elongation rate is equal to or greater than 30%.

6 . A method for manufacturing an acid-resistant steel sheet, comprising:
heating a slab including, by wt %, equal to or less than 0.1% of C (excluding 0%) and 2.0 to 4.0% of Si, and a remainder of Fe and inevitable impurities; manufacturing a hot rolled steel sheet by hot rolling the slab; and acidifying the hot rolled steel sheet in an acid aqueous solution of equal to or greater than 25 wt % for ten seconds or more.

7 . The method of claim 6 , wherein
the heating of a slab includes heating the slab at equal to or greater than 1200° C.

8 . The method of claim 6 , wherein
in the manufacturing of hot rolled steel sheet, a finish rolling temperature is equal to or greater than Ara.

9 . The method of claim 6 , further comprising,
after the manufacturing of a hot rolled steel sheet, winding the hot rolled steel sheet at 550 to 750° C.

10 . The method of claim 6 , further comprising,
after the manufacturing of a hot rolled steel sheet, cold rolling the hot rolled steel sheet.

11 . The method of claim 6 , further comprising,
after the manufacturing of a hot rolled steel sheet, annealing the hot rolled steel sheet.

Assignees

• Posco

Inventors

• Jo Minho
• Lee Byoung Ho
• Hong Young-Kwang

Classifications

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• C23G1/08

  Iron or steel · CPC title

• C23G1/081

  solutions containing H2SO4 · CPC title

• C23G1/085

  solutions containing HNO3 · CPC title

• C21D6/008

  containing Si · CPC title