Alloyed hot-dip galvanized steel sheet
AssigneeNippon Steel Corporation
InventorsKatsuya Nakano, Shuntaro Matsuyama, Taihei Kaneto
Life of this patent
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Abstract
An alloyed hot-dip galvanized steel sheet excellent in appearance and press-formability, comprising a base steel sheet having a predetermined chemical composition. If the base steel sheet has a chemical composition containing, by mass %, Mn: 0.01 to 1.30%, the predetermined relationships of formulas (1) and (3) are satisfied and if the base steel sheet has a chemical composition containing, by mass %, Mn: 1.70 to 2.00%, the predetermined relationships of formulas (2) and (3) are satisfied. The amounts of Mn, P, S, Ti, and Nb detected in the extraction residue of the base steel sheet satisfy the predetermined relationship of formula (4). The average grain diameter of the base steel sheet is 7.5 μm or less.
Claims7
An alloyed hot-dip galvanized steel sheet, comprising a base steel sheet and plating layer, wherein
- a chemical composition of the base steel sheet comprises, by mass %,
- C:
- 0.0005 to 0.0100%,
- Si:
- 0.01 to 0.50%,
- Mn:
- 0.01 to 1.30% or,
- P:
- 0.100% or less,
- S:
- 0.010% or less,
- N:
- 0.0200% or less,
- Ti:
- 0.040 to 0.180%,
- Nb:
- 0 to 0.100%,
- B:
- 0.0005 to 0.0100%,
- Al:
- 0 to 1.000%,
- Cu:
- 0 to 1.000%,
- Cr:
- 0 to 2.000%,
- Ni:
- 0 to 0.500%,
- Mo:
- 0 to 3.000%,
- W:
- 0 to 0.100%,
- V:
- 0 to 1.000%,
- O:
- 0 to 0.020%,
- Ta:
- 0 to 0.100%,
- Co:
- 0 to 3.000%,
- Sn:
- 0 to 1.000%,
- Sb:
- 0 to 0.500%,
- As:
- 0 to 0.050%,
- Mg:
- 0 to 0.050%,
- Zr:
- 0 to 0.050%,
- Ca:
- 0 to 0.0500%,
- REM:
- 0 to 0.0500%, and
- a balance:
- Fe and impurities,
- formulas (1) and (3) are satisfied,
- the amounts of Mn, P, S, Ti, and Nb in an extraction residue of the base steel sheet obtained by analysis of the extraction residue of the base steel sheet satisfy formula (4), and
- the average grain diameter of the base steel sheet is 7.5 μm or less:
- 1
-
- 3
-
- 0
- ≤
- 100
- [
- Si
- ]
- +
- 40
- [
- Mn
- ]
- +
- 900
- [
- P
- ]
- (
- 1
- )
- 15
-
- (
- 2
- [
- C
- ]
- -
- (
- [
- Ti
- ]
- -
- 4
- [
- N
- ]
- )
- /
- 3
- -
- [
- Nb
- ]
- /
- 8
- )
- +
- 7
- [
- P
- ]
- +
- [
- Si
- ]
- +
- 20
- [
- B
- ]
- ≤
- 0.75
- (
- 3
- )
- [
- C
- ]
- /
- 12
- ≤
- [
- X
- T
-
- i
- ]
- /
- 48
- +
- [
- X
- N
-
- b
- ]
- /
- 9
-
- 3
- ≤
- [
- C
- ]
- /
- 12
- +
- [
- N
- ]
- /
- 14
- +
- [
- X
- P
- ]
- /
- 31
- -
- (
- [
- X
- S
- ]
- /
- 32
- -
- [
- X
- M
-
- n
- ]
- /
- 5
-
- 5
- )
- (
- 4
- )
- in the above formulas,
- [C], [Si], [Mn], [P], [N], [Ti], and [Nb] are contents (mass %) of the elements in the chemical composition, and
- [XTi], [XNb], [XP], [XS], and [XMn] are expressed by formulas (A) to (E):
- [XTi]=[(Ti mass in extraction residue)/(mass of electrolyzed base steel sheet)]×100 (A)
- [XNb]=[(Nb mass in extraction residue)/(mass of electrolyzed base steel sheet)]×100 (B)
- [XP]=[(P mass in extraction residue)/(mass of electrolyzed base steel sheet)]×100 (C)
- [XS]=[(S mass in extraction residue)/(mass of electrolyzed base steel sheet)]×100 (D)
- [XMn]=[(Mn mass in extraction residue)/(mass of electrolyzed base steel sheet)]×100 (E).
Dependencies are inferred from the claim text.