US2024271240A1PendingUtilityA1
Martensitic stainless steel with improved strength and corrosion resistance, and manufacturing method therefor
Est. expiryDec 21, 2040(~14.4 yrs left)· nominal 20-yr term from priority
C21D 8/02C22C 38/46C22C 38/44C22C 38/42C22C 38/04C22C 38/02C22C 38/001C21D 2211/008C21D 8/0268C21D 8/0263C21D 8/0236C21D 8/0226C21D 6/008C21D 6/005C21D 6/004C21D 1/18C21D 8/0247C21D 9/46C21D 6/02C21D 1/22C21D 2211/004C21D 2211/005C21D 1/26C21D 1/25C21D 9/0081C21D 8/0205
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Claims
Abstract
Disclosed is a martensitic stainless steel with improved strength and corrosion resistance. The disclosed martensitic stainless steel sheet comprises, in percent by weight (wt %), 0.3 to 0.5% of C, 0.01 to 0.025% of N, 0.3 to 0.5% of Si, 0.4 to 0.6 of Mn, 13.1 to 14.5% of Cr, 0.95 to 1.10% of Mo, 0.05 to 0.3% of V, 0.3 to 0.5% of Ni, 0.001 to 0.5% of Cu, and the balance being Fe and inevitable impurities, and satisfies Formula (1). Formula (1): 16.4≤(Cr+3.3Mo+16N)*(Mo+V)≤23.3, wherein Cr, N, Mo, and V denote the contents (wt %) of respective elements.
Claims
exact text as granted — not AI-modified1 . A hot-rolled annealed martensitic stainless steel sheet with improved strength and corrosion resistance comprising, in percent by weight (wt %), 0.3 to 0.5% of C, 0.01 to 0.025% of N, 0.3 to 0.5% of Si, 0.4 to 0.6 of Mn, 13.1 to 14.5% of Cr, 0.95 to 1.10% of Mo, 0.05 to 0.3% of V, 0.3 to 0.5% of Ni, 0.001 to 0.5% of Cu, and the reminder of Fe and inevitable impurities, and satisfying Formula (1) below:
16.4
≤
(
Cr
+
3.3
Mo
+
16
N
)
*
(
Mo
+
V
)
≤
23.3
Formula
(
1
)
wherein Cr, N, Mo, and V denote contents (wt %) of elements, respectively.
2 . The hot-rolled annealed martensitic stainless steel sheet of claim 1 , wherein Formula (2) below is satisfied:
-
14
≤
-
36442
+
248
C
+
365
Cr
+
373
Mo
+
530
V
+
365
Fe
+
350
Si
+
312
Mn
+
331
Ni
+
506
Cu
≤
50
Formula
(
2
)
wherein C, Cr, Mo, V, Fe, Mn, Ni, and Cu denote wt % of the respective elements.
3 . The hot-rolled annealed martensitic stainless steel sheet of claim 1 , wherein Formula (3) below is satisfied:
0.37
≤
C
+
N
≤
0.43
.
Formula
(
3
)
4 . The hot-rolled annealed martensitic stainless steel sheet of claim 1 , wherein Formula (4) below is satisfied:
1.
≤
Mo
+
V
≤
1.35
.
Formula
(
4
)
5 . The hot-rolled annealed martensitic stainless steel sheet of claim 1 , further comprising:
a ferrite as a base structure; a primary carbide represented by (Cr, Fe, Mo, V) 7 C 3 ; and a secondary carbide represented by (Cr, Fe, Mo, V) 23 C 6 .
6 . The hot-rolled annealed martensitic stainless steel sheet of claim 5 , wherein the wt % of (Mo+V) in the primary carbide is 2.93 to 5.67%.
7 . The hot-rolled annealed martensitic stainless steel sheet of claim 5 , wherein the wt % of (Mo+V) in the secondary carbide is 12.2 to 14.8%.
8 . The hot-rolled annealed martensitic stainless steel sheet of claim 1 , wherein a particle size of the primary carbide is 10 μm or less.
9 . The hot-rolled annealed martensitic stainless steel sheet of claim 1 , wherein a carbide deviation is 10 pieces/100 μm 2 or less in a longitudinal direction.
10 . The hot-rolled annealed martensitic stainless steel sheet of claim 1 , wherein, after cold-rolled, a distribution density of carbide is 42 to 58 pieces/100 μm 2 .
11 . A method of manufacturing a martensitic stainless steel with improved strength and corrosion resistance, the method comprising:
hot-rolling a slab including, in percent by weight (wt %), 0.3 to 0.5% of C, 0.01 to 0.025% of N, 0.3 to 0.5% of Si, 0.4 to 0.6% of Mn, 13.1 to 14.5% of Cr, 0.95 to 1.10% of Mo, 0.05 to 0.3% of V, 0.3 to 0.5% of Ni, 0.001 to 0.5% of Cu, and the reminder of Fe and inevitable impurities, and satisfying Formula (1) below; batch-annealing in a temperature range of 600 to 900° C. immediately after hot-rolled; cold-rolling the hot-rolled annealed material; and hardening heat treatment of the cold-rolled material;
16.4
≤
(
Cr
+
3.3
Mo
+
16
N
)
*
(
Mo
+
V
)
≤
23.3
Formula
(
1
)
wherein Cr, N, Mo, and V denote contents (wt %) of elements, respectively.
12 . The method of claim 11 , wherein the hot-rolled annealed material further comprises:
a ferrite as a base structure; a primary carbide represented by (Cr, Fe, Mo, V) 7 C 3 ; and a secondary carbide represented by (Cr, Fe, Mo, V) 23 C 6 .
13 . The method of claim 11 , wherein the wt % of (Mo+V) in the primary carbide is 2.93 to 5.67%.
14 . The method of claim 11 , wherein the wt % of (Mo+V) in the secondary carbide is 12.2 to 14.8%.
15 . The method of claim 11 , wherein a particle size of the primary carbide is 10 μm or less.
16 . The method of claim 11 , wherein, after cold-rolled, 42 to 58 pieces/100 μm 2 or less of carbides are distributed therein.
17 . The method of claim 11 , wherein the hardening heat treatment further comprises:
quenching at a temperature range of 980 to 1,050° C.; and tempering at a temperature of 400 to 600° C. for 1 minute to 1 hour.
18 . The method of claim 17 , wherein the Vickers hardness is 520 to 650 Hv after the hardening heat treatment.
19 . The method of claim 11 , further comprising satisfying Formula (2) below:
-
14
≤
-
36442
+
248
C
+
365
Cr
+
373
Mo
+
530
V
+
365
Fe
+
350
Si
+
312
Mn
+
331
Ni
+
506
Cu
≤
50
Formula
(
2
)
wherein C, Cr, Mo, V, Fe, Si, Mn, Ni, and Cu denote wt % of the respective elements.
20 . The method of claim 11 , further comprising satisfying Formula (3) and (4) below:
0.37
≤
C
+
N
≤
0.43
,
and
Formula
(
3
)
1.
≤
Mo
+
V
≤
1.35
.
Formula
(
4
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