Galvanized steel sheet for hot forming

Patent metadata

Field	Value
Publication number	US-2015314568-A1
Application number	US-201314417876-A
Country	US
Kind code	A1
Filing date	Aug 5, 2013
Priority date	Aug 7, 2012
Publication date	Nov 5, 2015
Grant date	—

Abstract

A galvanized steel sheet for hot forming, the galvanized steel sheet including a galvanized film provided on a surface of a steel sheet,
wherein the steel sheet has a chemical composition consisting of, in mass %, C: 0.02% to 0.58%, Mn: 0.5% to 3.0%, sol. Al: 0.005% to 1.0%, a predetermined element(s) as necessary; Si: less than or equal to 2.0%, P: less than or equal to 0.03%, S: less than or equal to 0.004%, N: less than or equal to 0.01%, and the balance: Fe and impurities, wherein a content of Mn in a portion from an interface of the steel sheet and the galvanized film to a depth of 5 μm is more than or equal to 0.3 mass %, wherein the galvanized film has a plating coverage of 40 g/m 2 to 110 g/m 2 , an Al content of more than or equal to 150 mg/m 2 within the galvanized film, and an Al concentration of less than or equal to 0.5 mass %, and wherein the galvanized steel sheet is used for an application in which the galvanized steel sheet is heated to 700° C. or above and is then subjected to hot forming.

First claim

1 - 6 . (canceled)

7 . A galvanized steel sheet for hot forming, the galvanized steel sheet comprising a galvanized film provided on a surface of a steel sheet,
wherein the steel sheet has a chemical composition consisting of, in mass %, C: 0.02% to 0.58%, Mn: 0.5% to 3.0%, sol. Al: 0.005% to 1.0%, Ti: 0% to 0.20%, Nb: 0% to 0.20%, V: 0% to 1.0%, W: 0% to 1.0%, Cr: 0% to 1.0%, Mo: 0% to 1.0%, Cu: 0% to 1.0%, Ni: 0% to 1.0%, B: 0% to 0.010%, Mg: 0% to 0.05%, Ca: 0% to 0.05%, REM: 0% to 0.05%, Bi: 0% to 0.05%, Si: less than or equal to 2.0%, P: less than or equal to 0.03%, S: less than or equal to 0.004%, N: less than or equal to 0.01%, and the balance: Fe and impurities, wherein a content of Mn in a portion from an interface of the steel sheet and the galvanized film to a depth of 5 μm is more than or equal to 0.3 mass %, wherein the galvanized film has a plating coverage of 40 g/m 2 to 110 g/m 2 , an Al content of more than or equal to 150 mg/m 2 within the galvanized film, and an Al concentration of less than or equal to 0.5 mass %, and wherein the galvanized steel sheet is used for an application in which the galvanized steel sheet is heated to 700° C. or above and is then subjected to hot forming.

8 . The galvanized steel sheet for hot forming according to claim 7 , wherein the steel sheet comprises one or more selected from the group consisting of, in mass %,
Ti: 0.01% to 0.20%, Nb: 0.01% to 0.20%, V: 0.1% to 1.0%, and W: 0.1% to 1.0%.

9 . The galvanized steel sheet for hot forming according to claim 7 , wherein the steel sheet comprises one or more selected from the group consisting of, in mass %,
Cr: 0.1% to 1.0%, Mo: 0.1% to 1.0%, Cu: 0.1% to 1.0%, Ni: 0.1% to 1.0%, and B: 0.0010% to 0.010%.

10 . The galvanized steel sheet for hot forming according to claim 8 , wherein the steel sheet comprises one or more selected from the group consisting of, in mass %,
Cr: 0.1% to 1.0%, Mo: 0.1% to 1.0%, Cu: 0.1% to 1.0%, Ni: 0.1% to 1.0%, and B: 0.0010% to 0.010%.

11 . The galvanized steel sheet for hot forming according to claim 7 , wherein the steel sheet comprises one or more selected from the group consisting of, in mass %,
Mg: 0.0005% to 0.05%, Ca: 0.0005% to 0.05%, and REM: 0.0005% to 0.05%.

12 . The galvanized steel sheet for hot forming according to claim 8 , wherein the steel sheet comprises one or more selected from the group consisting of, in mass %,
Mg: 0.0005% to 0.05%, Ca: 0.0005% to 0.05%, and REM: 0.0005% to 0.05%.

13 . The galvanized steel sheet for hot forming according to claim 9 , wherein the steel sheet comprises one or more selected from the group consisting of, in mass %,
Mg: 0.0005% to 0.05%, Ca: 0.0005% to 0.05%, and REM: 0.0005% to 0.05%.

14 . The galvanized steel sheet for hot forming according to claim 10 , wherein the steel sheet comprises one or more selected from the group consisting of, in mass %,
Mg: 0.0005% to 0.05%, Ca: 0.0005% to 0.05%, and REM: 0.0005% to 0.05%.

15 . The galvanized steel sheet for hot forming according to claim 7 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

16 . The galvanized steel sheet for hot forming according to claim 8 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

17 . The galvanized steel sheet for hot forming according to claim 9 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

18 . The galvanized steel sheet for hot forming according to claim 10 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

19 . The galvanized steel sheet for hot forming according to claim 11 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

20 . The galvanized steel sheet for hot forming according to claim 12 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

21 . The galvanized steel sheet for hot forming according to claim 13 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

22 . The galvanized steel sheet for hot forming according to claim 14 , wherein the steel sheet comprises, in mass %,
Bi: 0.0002% to less than or equal to 0.05%.

23 . The galvanized steel sheet for hot forming according to claim 7 , wherein the galvanized steel sheet is an alloyed hot dip galvanized steel sheet.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Takahashi Hiroyuki
• Imai Kazuhito
• Nishibata Hitomi

Classifications

• C21D8/02 Primary

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

• C21D8/0247

  characterised by the heat treatment · CPC title

• C23C2/40

  Plates; Strips · CPC title

• C22C38/06

  containing aluminium · CPC title

• C22C38/26

  with niobium or tantalum · CPC title