US2025230533A1PendingUtilityA1
Low temperature hardenable steels with excellent machinability
Est. expiryMay 7, 2032(~5.8 yrs left)· nominal 20-yr term from priority
Inventors:Isaac Valls Anglés
C22C 38/54C22C 38/48C22C 38/46C22C 38/42C22C 38/52C22C 38/50C22C 38/44C22C 38/38C22C 38/32C22C 38/30C22C 38/28C22C 38/26C22C 38/24C22C 38/04C22C 38/02C21D 2211/008C21D 2211/003C21D 2211/002C21D 2211/001C22C 38/22C22C 38/18C21D 9/00C21D 1/30C21D 6/002C22C 38/12C22C 38/14C22C 38/08C22C 38/005C22C 38/002C22C 38/58
75
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0
Cited by
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References
0
Claims
Abstract
The present invention relates to the application of at least partially bainitic or interstitial martensitic heat treatments on steels, often tool steels or steels that can be used for tools. The first tranche of the heat treatment implying austenitization is applied so that the steel presents a low enough hardness to allow for advantageous shape modification, often trough machining. Thus a steel product is obtained which can be shaped with ease and whose hardness can be raised to a higher working hardness with a simple heat treatment at low temperature (below austenitization temperature).
Claims
exact text as granted — not AI-modified1 . A steel with the following composition, all percentages being indicated in weight percent:
%
Ceq
=
0.21
-
3.
%
C
=
0.21
-
3.
%
N
=
0
-
2.2
%
B
=
0
-
2.
%
Cr
=
0.
-
14
%
Ni
=
0
-
6.
%
Si
=
0
-
2.
%
Mn
=
0
-
3
%
Al
=
0
-
2.5
%
Mo
=
0
-
15
%
W
=
0
-
15
%
Ti
=
0
-
4
%
Ta
=
0
-
4
%
Zr
=
0
-
12
%
Hf
=
0
-
4
%
V
=
0
-
12
%
Nb
=
0
-
4
%
Cu
=
0
-
2
%
Co
=
0
-
6
the rest consisting of iron and trace elements wherein,
%
Ceq
=
%
C
+
0.86
*
%
N
+
1.2
*
%
B
,
said steel having a microstructure comprising at least 50% vol. bainite.
2 . The steel according to claim 1 , wherein % C is 0.33% or more.
3 . The steel according to claim 1 , wherein % Ceq is 1.8% or less.
4 . The steel according to claim 1 , wherein % Cr+% W+% Mo+% V+% Nb+% Zr is above 4.0%.
5 . The steel according to claim 1 , wherein % Al is less than 0.6%.
6 . The steel according to claim 1 , wherein % Cr is below 3%.
7 . The steel according to claim 1 , wherein % Si is less than 0.8%.
8 . The steel according to claim 1 , wherein carbide formers W, Zr, Ta, Hf, Nb, La, Ac are more than 0.08%.
9 . The steel according to claim 1 , wherein % V is less than 1%.
10 . The steel according to claim 1 , wherein % V is more than 0.2%.
11 . The steel according to claim 1 , wherein % V is more than 0.3%.
12 . The steel according to claim 1 , wherein said steel has a microstructure comprising one or more of retained austenite, and carbide formers stronger than iron which are present in the solid solution.
13 . The steel according to claim 1 , wherein said steel has a microstructure comprising carbide formers stronger than iron which are present in the solid solution.
14 . The steel according to claim 1 , wherein at least 8% of its carbon content is present in the form of carbides not belonging to the bainitic and/or interstitial martensitic microstructure.
15 . The steel according to claim 1 , wherein at least 30% vol. of all carbides have 50% at % or more iron of all metallic constituents of the carbide.
16 . The steel according to claim 1 , wherein the bainite is at least 65% vol.
17 . The steel according to claim 1 , wherein the bainite is at least 76% vol.
18 . The steel according to claim 1 , wherein at least 50% vol % of the bainite is high temperature bainite.
19 . The steel according to claim 1 , wherein the bainite present comprises tempered bainite.
20 . The steel according to claim 1 , wherein the steel is characterized by a low scattering structure characterized by a thermal diffusivity higher than 8 mm 2 /s.Join the waitlist — get patent alerts
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