US2013216856A1PendingUtilityA1
Mechanical component and method of surface hardening
Est. expiryJul 2, 2030(~3.9 yrs left)· nominal 20-yr term from priority
Inventors:Marco Burtchen
C22C 38/18C21D 1/42C22C 38/00C22C 38/02C22C 38/04Y10T428/12458C21D 2221/10C21D 9/00C22C 38/002C21D 1/10Y02P10/25
32
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Claims
Abstract
Mechanical component having a surface at least one part of which has been surface hardened by induction heating. A cross section of the mechanical component through the surface exhibits a hardness H surface at the surface, and remains substantially equal through a first region, a hardness H core at the non-hardened core of the mechanical component and remains substantially equal through a third region and a transition, second region spanning between the first and third regions. The hardness profile in the first region has an average hardness Y 1 , and the hardness profile in the third region has an average hardness Y 3 . If a line is drawn on the hardness profile in the second region between the points (formula) and (formula), where 0<K<2, the hardness of the mechanical component in the second region determined along the line decreases by less than 50 HRC per mm.
Claims
exact text as granted — not AI-modified1 . A mechanical component having a surface, wherein at least one part of said surface has been surface hardened by induction heating,
whereby a cross section of the mechanical component through said surface exhibits a hardness H surface at said surface and a hardness H core at the non-hardened core of the mechanical component, wherein the hardness profile of said cross section exhibits: a first region whose hardness is substantially equal to the hardness H surface at said surface, a third region whose hardness is substantially equal to the hardness H core at the non-hardened core of the mechanical component, and a second region between said first and third regions, wherein the hardness profile in the first region has an average hardness Y 1 , and the hardness profile in the third region has an average hardness Y 3 , and whereby if a line is drawn on the hardness profile in said second region between the points
Y
1
+
Y
3
2
+
(
Y
1
-
Y
3
4
)
*
k
and
Y
1
+
Y
3
2
-
(
Y
1
-
Y
3
4
)
*
k
,
where 0<k<2, the hardness of said mechanical component in said second region determined along said line decreases by less than 50 HRC per mm.
2 . The mechanical component according to claim 1 , wherein said hardness of the mechanical component in said second region determined along said line decreases by one of:
less than 30 HR per mm, less than 25 HRC per mm, less than 20 HRC per mm, and less than 15 HRC per mm.
3 . The mechanical component according to claim 1 , wherein said hardness H surface at said surface is between 55-75 HRC.
4 . The mechanical component according to claim 1 , wherein said hardness H core at the non-hardened core of the mechanical component is between 15-30 HRC.
5 . The mechanical component according to claim 4 , characterized in that said first region extends from the surface to a depth of up to 6 mm below said surface.
6 . The mechanical component according to claim 1 , wherein said mechanical component is fabricated into a form of at least one of a steel bar, a cylinder, a rod, a piston, a shaft, and a beam.
7 . A method for surface hardening at least part of the surface of a mechanical component, comprising steps of:
heating said at least one part of the surface with an electromagnetic induction coil to the at least a ferrite/austenite transformation temperature by induction heating, maintaining said at least one part of said surface at least said ferrite/austenite transformation temperature in order to allow for sufficient heat transport below the surface resulting in a sufficient austenitization of the at least one part, and quenching said at least one part of the surface in order to obtain a cross section of the mechanical component through said surface which exhibits: a hardness H surface at said surface and a hardness H core at the non-hardened core of the mechanical component, whereby the hardness profile of said cross section exhibits:
a first region whose hardness is substantially equal to the hardness H surface at said surface,
a third region whose hardness is substantially equal to the hardness H core at the non-hardened core of the mechanical component and
a second region between said first and third regions,
wherein the hardness profile in the first region has an average hardness Y 1 , and the hardness profile in the third region has an average hardness Y 3 , and
whereby if a line is drawn on the hardness profile in the third region has an average hardness Y 3 , and
whereby if a line is drawn on the hardness profile in said second region between the points
Y
1
+
Y
3
2
+
(
Y
1
-
Y
3
4
)
*
k
and
Y
1
+
Y
3
2
-
(
Y
1
-
Y
3
4
)
*
k
,
where 0<k<2, the hardness of said mechanical component in said second region determined along said line decreases by less than 50 HRC per mm.
8 . The method according to claim 7 , further comprises the steps of:
heating said at least one part of the surface with an electromagnetic induction coil to at least the ferrite/austenite transformation temperature by induction heating, maintaining said at least one part of the interior surface at that temperature in order to allow for sufficient heat transport below the surface resulting in a sufficient austenitization of the at least one part, and quenching said at least one part of the surface in order to obtain a cross section of the mechanical component through said surface which exhibits a hardness H surface at said surface and a hardness H core at the non-hardened core of the mechanical component, and in which the hardness of the mechanical component in said second region determined along said line decreases by less than one of: less than 30 HRC per mm, less than 25 HRC per mm, less than 20 HRC per mm, and less than 15 HRC per mm.
9 . The method according to claim 7 , further comprising a step of maintaining said at least one part of the interior surface at said temperature for at least one of 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, and greater than 50 seconds.
10 . The method according to claim 7 , wherein the hardness profile of said cross section exhibits:
a first region whose hardness is substantially equal to the hardness H surface at said surface, a third region whose hardness is substantially equal to the hardness H core at the non-hardened core of the mechanical component and a second region between said first and third region in which the hardness profile exhibits a smooth transition between the hardness of said first and third regions.
11 . The method according to claim 10 , wherein said first region extends from the surface to a depth of up to 6 mm below said surface.
12 . The method according to claim 7 , wherein said mechanical component is fabricated into a form of at least one of a steel bar, a cylinder, a rod, a piston, a shaft, and a beam.
13 . The mechanical component according to claim 1 , wherein said hardness H surface at said surface is between 58-63 HRC.
14 . The mechanical component according to claim 4 , wherein said first region extends from said surface to a depth of between 1-4 mm below said surface.
15 . The method according to claim 10 , wherein said first region extends from the surface to a depth from 2 through 4 mm below said surface.Join the waitlist — get patent alerts
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