US2014056749A1PendingUtilityA1
Hot-work tool steel and a process for making a hot-work tool steel
Est. expiryMar 4, 2031(~4.6 yrs left)· nominal 20-yr term from priority
C21D 8/00B22F 1/00B22F 1/145C22C 38/38C22C 33/0264C22C 38/22C21D 6/007C22C 38/32C21D 1/25C22C 38/04C22C 38/54B22F 3/14C22C 38/02C21D 6/02C22C 38/44C21D 6/004C22C 38/58C22C 38/46C22C 38/30C22C 38/52C21D 6/005C22C 38/001C21D 1/32B22F 2999/00C21D 6/002C22C 38/24C22C 38/06B22F 2998/10C21D 2211/004C21D 9/00C21D 6/008C21D 9/0068C21D 8/005
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Claims
Abstract
A low-chromium hot-work tool steel consisting of (in wt-%): C 0.08-0.40, N 0.015-0.30, C+N 0.30-0.50, Cr 1-4, Mo 1.5-3, V 0.8-1.3, Mn 0.5-2, Si 0.1-0.5, optionally Ni<3, Co≦5, B<0.01, Fe balance apart from impurities, and a process for making a low-chromium hot-work tool steel article having increased tempering resistance.
Claims
exact text as granted — not AI-modified1 . A low-chromium hot-work tool steel consisting of (in wt-%):
C
0.08-0.40
N
0.015-0.30
C + N
0.30-0.50
Cr
1-4
Mo
1.5-3
V
0.8-1.3
Mn
0.5-2
Si
0.1-0.5
optionally
Ni
<3
Co
≦5
B
<0.01
Fe balance apart from impurities.
2 . A low-chromium hot-work tool steel according to claim 1 fulfilling one or more the following conditions (in wt-%):
C
0.20-0.38
preferably 0.30-0.35
N
0.03-0.30
preferably 0.03-0.10
C + N
0.30-0.50
preferably 0.36-0.44
Cr
1-3
preferably 1.2-2.6
Mo
1.9-2.9
preferably 2.2-2.8
V
1.0-1.3
preferably 1.15-1.25
Mn
1-2
preferably 1.1-1.9
Si
0.1-0.5
preferably 0.2-0.4
Ni
<1
preferably <0.25
Co
<4
preferably <0.20
B
0.001-0.01
preferably 0.001-0.005
3 . A low-chromium hot-work tool steel according to claim 1 fulfilling more of the following conditions (in wt-%):
C
0.25-0.35
preferably 0.27-0.34
N
0.04-0.30
preferably 0.04-0.10
C + N
0.38-0.42
Cr
1.3-2.5
preferably 1.4-2.3
4 . A low-chromium hot-work tool steel according to claim 3 fulfilling one or more of the following conditions (in wt-%):
N
0.042-0.15
preferably 0.045-0.12
C + N
0.39-0.41
Cr
1.3-2.3
preferably 1.4-2.1
5 . A low-chromium hot-work tool steel according to claim 1 fulfilling one or more of the following conditions (in wt-%):
C
0.20-0.35
preferably 0.30-0.34
N
0.042-0.12
preferably 0.045-0.12
C + N
0.39-0.41
Cr
1.4-1.9
preferably 1.5-1.7
Mo/V
1.8-2.3
preferably 1.9-2.1
Cr/V
<2
preferably <1.8
6 . A low-chromium hot-work tool steel according to claim 1 consisting of (in wt-%):
C
0.20-0.40
N
0.03-0.30
C + N
0.30-0.50
Cr
1.2-2.3
Mo
1-3
V
0.8-1.3
Mn
1-2
Si
0.1-0.4
Ni
<1
optionally
Co
3-5
B
0.001-0.01
Mo/V
1.8-2.3
Cr/V
<2
Fe balance apart from impurities.
7 . A low-chromium hot-work tool steel according to claim 1 consisting of (in wt-%):
C
0.20-0.40
N
0.03-0.30
C + N
0.30-0.50
Cr
1.2-2.3
Mo
1.5-3
V
0.8-1.3
Mn
1-2
Si
0.1-0.4
Ni
<1
optionally
Co
3-5
B
0.001-0.01
Mo/V
1.8-2.3
Cr/V
<2
Fe balance apart from impurities.
8 . A low-chromium hot-work tool steel according to claim 1 consisting of (in wt-%):
C
0.20-0.40
N
0.04-0.30
C + N
0.30-0.50
Cr
1.2-2.3
Mo
1-3
V
0.8-1.3
Mn
1-2
Si
0.1-0.4
Ni
<1
Co
<0.2
optionally
B
0.001-0.01
Mo/V
1.8-2.3
Cr/V
<2
Fe balance apart from impurities.
9 . A low-chromium hot-work tool steel according to claim 1 consisting of (in wt-%):
C
0.20-0.38
N
0.04-0.30
C + N
0.36-0.44
Cr
1.2-2.3
Mo
1.9-2.9
V
0.8-1.3
Mn
1-2
Si
0.1-0.4
Ni
<0.25
Co
<0.20
optionally
B
0.001-0.01
Mo/V
1.8-2.3
Cr/V
<2
Fe balance apart from impurities.
10 . A low-chromium hot-work tool steel according to claim 1 consisting of (in wt-%):
C
0.30-0.34
N
0.04-0.09
C + N
0.37-0.43
Cr
1.4-1.9
Mo
2.2-2.8
V
1.0-1.3
Mn
1-2
Si
0.2-0.4
Ni
<0.25
Co
<0.20
optionally
B
0.001-0.005
Mo/V
1.8-2.3
Cr/V
<2
Fe balance apart from impurities.
11 . A process for making a low-chromium hot-work tool steel article having increased tempering resistance, comprising:
a) providing a steel as defined in any of the preceding claims; b) forming a steel article from the steel; c) austenitizing the steel article obtained in step b) at a temperature of at most 1200° C. for a time on the order of half an hour followed by quenching; and d) tempering the quenched steel article for a time of 2 hours at least twice at a temperature between 500 and 700° C.
12 . A process as claimed in claim 11 , comprising carrying out the austenitizing of the steel article at a temperature of 1050-1150° C., preferably at 1080-1150° C.
13 . A process as claimed in claim 11 , comprising carrying out the tempering of the quenched steel article at a temperature of 550-680° C., preferably 600-650° C. and even more preferred at 625-650° C.
14 . A process as claimed in claim 11 , further comprising incorporating the nitrogen by first manufacturing a steel powder of essentially the desired composition, except for the nitrogen, then nitriding this powder in solid state by nitrogen gas to provide the desired composition, and thereafter hot pressing the powder to form an ingot.
15 . A process as claimed in claim 11 , further comprising the steps of homogenizing, forging and soft annealing the ingot before austenitizing.Join the waitlist — get patent alerts
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