US2026009116A1PendingUtilityA1
Method and device for applying a layer onto a flat steel product
Est. expiryJun 30, 2042(~15.9 yrs left)· nominal 20-yr term from priority
C23C 2/06C22C 18/04C22C 18/00C23C 2/52C23C 2/51C23C 2/20C23C 2/003C23C 2/18C23C 2/16C23C 2/14C23C 2/50C23C 2/525
52
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Claims
Abstract
A Device for applying a layer to a flat steel product includes a zinc alloy melt bath with an input side, an exit side, a stripping nozzle device which comprises at least one nozzle lip gap and which is arranged in the area of the exit side in such a way that the still liquid layer at the flat steel product is blowable off with gas which emerges through the nozzle lip gap. The device is configured to make at least one of increasing the bath temperature of the alloy melt bath if the current absolute local air humidity is reduced and vice versa, and/or reducing the thickness of the nozzle lip gap if the current absolute local air humidity is reduced and vice versa, and/or reducing the distance between the nozzle lip gap and the side of the flat steel product.
Claims
exact text as granted — not AI-modified1 . Method for applying a layer ( 10 ) having a target thickness to at least one side of a flat steel product ( 100 ) by moving the flat steel product ( 100 ) through a zinc alloy melt bath ( 11 ), and by emitting gas (G) through a nozzle lip gap ( 17 ) of at least one gas nozzle ( 15 ) towards the flat steel product ( 100 ) on the exit side (A) thereof, for blowing off the layer ( 10 ) to the target thickness, the zinc alloy of the zinc alloy melt bath ( 11 ) having the following composition:
an aluminum content which is in the range between 1.0 percent by weight and 3.5 percent by weight and preferably in the range between 1.3 percent by weight and 2.8 percent by weight, a magnesium content which is in the range between 1.0 percent by weight and 3.0 percent by weight and preferably in the range between 1.2 percent by weight and 2.2 percent by weight, and a remainder comprising zinc, optionally one or more additional elements selected from Si, Sb, Pb, Ti, Ca, Mn, Sn, Zr, Sr, La, Ce or Bi, the weight related content of each additional element being less than 0.1%, and unavoidable impurities, characterized in that at least one of the following adjustable parameters is adjusted as follows: increasing the bath temperature (TB) of the alloy melt bath ( 11 ) if the current absolute local air humidity (ƒ) is reduced and reducing the bath temperature (TB) of the alloy melt bath ( 11 ) if the current absolute local air humidity (ƒ) is increased, and/or reducing the thickness (d) of the nozzle lip gap ( 17 ) if the current absolute local air humidity (ƒ) is reduced and increasing the thickness (d) of the nozzle lip gap ( 17 ) if the current absolute local air humidity (ƒ) is increased, and/or reducing the distance (Z) between the nozzle lip gap ( 17 ) and the side of the flat steel product ( 100 ) if the current absolute local air humidity (ƒ) is reduced and increasing the distance (Z) between the nozzle lip gap ( 17 ) and the side of the flat steel product ( 100 ) if the current absolute local air humidity (ƒ) is increased, wherein the flow rate (D) of the gas (G) is additionally adjusted in order to keep the target thickness of the layer ( 10 ) to be applied essentially constant.
2 . Method according to claim 1 , characterized in that the layer ( 10 ) fulfils the following requirement(s):
target surface coating of the layer ( 10 ) per strip side being in the range of 20 g/m 2 to 200 g/m 2 , preferably in the range of 30 g/m 2 to 100 g/m 2 , and/or target thickness of the layer ( 10 ) per strip side being in the range of 3 μm to 30 μm, preferably in the range of 4.5 μm to 15 μm.
3 . Method according to claim 1 , characterized in that the adjustment of the said parameters is carried out for the following range in order to prevent marbling and/or toothpick defects at the layer ( 10 ):
absolute local air humidity (ƒ) in the range of 1 g/m 3 to 300 g/m 3 , preferably in the range of 1.08 g/m 3 to 51 g/m 3 .
4 . Method according to claim 1 , characterized in that a relationship between the current absolute local air humidity (ƒ) and the adjustable parameters is specified by means of a stripping efficiency (AWZ), the following condition having to be fulfilled for avoiding marbling and/or toothpick defects: f>AWZ.
5 . Method according to claim 4 , characterized in that the stripping efficiency (AWZ) is defined as follows:
AWZ
=
24.61
·
D
2
·
k
w
2
·
d
2
·
b
+
3639
·
b
v
-
45.42
wherein applies:
d being the thickness of the nozzle lip gap in mm
D being the effective flow (rate) D of gas G per strip side over the strip width (w) in Nm 3 /h
k being a unitless proportionality factor
W being the strip width of the flat steel product ( 100 ) in mm
2 b being the half-width of the pressure distribution of gas G at the stripe in mm
v being the strip speed in m/min.
6 . Method according to claim 4 , characterized in that the stripping efficiency (AWZ) is defined as follows:
AWZ
=
1
14
·
(
D
2
·
k
·
e
-
0.5
·
1.251
·
10
4
w
2
·
d
2
·
25.92
·
-
2
·
ln
(
0.5
)
b
2
+
6
·
10
4
v
·
-
b
2
2
·
ln
(
0.5
)
-
636
wherein applies:
d being the thickness of the nozzle lip gap in mm
D being the effective flow (rate) D of gas G per strip side over the strip width (w) in Nm 3 /h
k being a unitless proportionality factor
W being the strip width of the flat steel product ( 100 ) in mm
2 b being the half-width of the pressure distribution of gas G at the stripe in mm
v being the strip speed in m/min.
7 . Method according to claim 5 , characterized in that the following definitions apply when determining the values for the half half-width (b) and the proportionality factor (k) using the ratio of the distance (Z) to the thickness (d) of the nozzle lip gap ( 17 ):
Z
d
<
5.2
→
b
=
1.9
·
d
2
and
k
=
1
case
1.1
5.2
≤
Z
d
<
10
→
b
=
[
-
(
Z
d
)
4
·
3.22
·
10
-
4
+
(
Z
d
)
3
·
9.78
·
10
-
3
-
(
Z
d
)
2
·
8.39
·
10
-
2
+
(
Z
d
)
·
2.72
·
10
-
1
+
1.62
]
·
d
2
→
k
=
-
(
Z
d
)
4
·
6.05
·
10
-
4
+
(
Z
d
)
3
·
2.2
·
10
-
2
-
(
Z
d
)
2
·
2.89
·
10
-
1
+
(
Z
d
)
·
1.55
-
1.9
case
1.2
Z
d
≥
10
→
b
=
0.125
·
Z
and
k
=
6.5
·
d
Z
case
1.3
8 . Method according to claim 5 , characterized in that the following simplified definitions apply when determining the values for the half half-width (b) and the proportionality factor (k) using the ratio of the distance (Z) to the thickness (d) of the nozzle lip gap ( 17 ):
Z
d
<
7.6
→
b
=
1.9
·
d
2
and
k
=
1
case
2.1
Z
d
≥
7.6
→
b
=
0.125
·
Z
and
k
=
6.5
·
d
Z
case
2.2
9 . Method according to claim 1 , characterized in that
the thickness (d) of the nozzle lip gap ( 17 ) is in a range between 0.5 mm and 5 mm, preferably between 0.6 mm and 2 mm, particularly preferably between 0.8 mm and 1.5 mm, and/or the flow rate (D) is in the range of 200 Nm 3 per hour to 8000 Nm 3 per hour, and/or the spacing (Z) is in a range between 2 mm and 15 mm, preferably between 3 mm and 12 mm, and/or the strip speed (v) is in a range between 50 m/min and 200 m/min, preferably between 70 m/min and 150 m/min.
10 . Method according to claim 1 , characterized in that the bath temperature TB of the alloy melt bath ( 11 ) is in the range of 400 degrees Celsius<TB<480 degrees Celsius, preferably in the range of 409 degrees Celsius<TB<473 degrees Celsius, and particularly preferably in the range of 420 degrees Celsius<TB<460 degrees Celsius.
11 . Method according to claim 1 , characterized in that the absolute local air humidity (ƒ) is valid in two virtual cylinder volume segments which are limited on the one hand by a virtual cylinder surface which concentrically or almost concentrically encloses the at least one gas nozzle ( 15 ) and on the other hand by two planes running parallel to the flat steel product ( 100 ) on both sides of the flat steel product and at a distance(s) from the flat steel product ( 100 ), wherein the cylinder volume segments together have a volume in a range of 1 m 3 to 10 m 3 and preferably a volume of less than 2 m 3 , wherein the measurement of the absolute local air humidity (ƒ) is carried out directly or indirectly.
12 . Method according to claim 11 , characterized in that the absolute local air humidity (ƒ) is measured permanently or from time to time and, if the absolute local humidity (ƒ) is too low, the method is interrupted to adjust one or more of the adjustable parameters.
13 . Method according to claim 1 , characterized in that the application of the layer ( 10 ) is controlled by means of a controller ( 250 ) in such a way that, when the absolute local air humidity (ƒ) changes, one or more of the adjustable parameters are adjusted automatically and/or manually depending on the current absolute local air humidity (ƒ).
14 . Device ( 150 ) for applying a layer ( 10 ) to a flat steel product ( 100 ), comprising
a zinc alloy melt bath ( 11 ) having an input side (E), an exit side (A) and a deflector ( 13 ) for guiding the flat steel product ( 100 ) coming from the input side (E) at a strip speed (v) through the zinc alloy melt bath ( 11 ) to the exit side (A), a stripping nozzle device ( 14 ) which comprises at least one nozzle lip gap ( 17 ) and which is arranged in the area of the exit side (A) in such a way that the still liquid layer ( 10 ) at the flat steel product ( 100 ) is blowable off with gas (G) which emerges through the nozzle lip gap ( 17 ) in order to blow off the layer ( 10 ) to a target thickness, wherein the zinc alloy of the zinc alloy melt bath ( 11 ) has the following composition: an aluminum content which is in the range between 1.0 percent by weight and 3.5 percent by weight and preferably in the range between 1.3 percent by weight and 2.8 percent by weight, a magnesium content which is in the range between 1.0 percent by weight and 3.0 percent by weight and preferably in the range between 1.2 percent by weight and 2.2 percent by weight, and a remainder comprising zinc, optionally one or more additional elements selected from Si, Sb, Pb, Ti, Ca, Mn, Sn, Zr, Sr, La, Ce or Bi, the weight related content of each additional element being less than 0.1%, and unavoidable impurities, characterized in that the device ( 150 ) is adapted to or configured to make at least one of the following adjustments manually or automatically: increasing the bath temperature (TB) of the alloy melt bath ( 11 ) if the current absolute local air humidity (ƒ) is reduced and reducing the bath temperature (TB) of the alloy melt bath ( 11 ) if the current absolute local air humidity (ƒ) is increased, and/or reducing the thickness (d) of the nozzle lip gap ( 17 ) if the current absolute local air humidity (ƒ) is reduced and increasing the thickness (d) of the nozzle lip gap ( 17 ) if the current absolute local air humidity (ƒ) is increased, and/or reducing the distance (Z) between the nozzle lip gap ( 17 ) and the side of the flat steel product ( 100 ) if the current absolute local air humidity (ƒ) is reduced and increasing the distance (Z) between the nozzle lip gap ( 17 ) and the side of the flat steel product ( 100 ) if the current absolute local air humidity (ƒ) is increased, wherein additionally the flow rate (D) of the gas (G) is automatically adjusted to keep the target thickness of the layer ( 10 ) to be applied essentially constant.
15 . Device ( 150 ) according to claim 14 , characterized in that the layer ( 10 ) to be applied fulfils the following requirement:
target surface coating of the layer ( 10 ) per strip side being in the range of 20 g/m 2 to 200 g/m 2 , preferably in the range of 30 g/m 2 to 100 g/m 2 , and/or target thickness of the layer ( 10 ) per strip side being in the range of 3 μm to 30 μm, preferably in the range of 4.5 μm to 15 μm.
16 . Device ( 150 ) according to claim 14 , characterized in that the adjustment of the adjustable parameters for the following range is carriable out in order to prevent marbling and/or toothpick defects at the layer ( 10 ):
absolute local air humidity (ƒ) in the range of 1 g/m 3 to 300 g/m 3 , preferably in the range of 1.08 g/m 3 to 51 g/m 3 .
17 . Device ( 150 ) according to claim 14 , characterized in that it additionally comprises:
at least one humidity sensor ( 51 ), which is arranged in the local surrounding of the stripping nozzle device ( 14 ), a controller ( 250 ) which is connectable to the at least one humidity sensor ( 51 ) by means of communication to obtain, continuously or from time to time, a measurement value or signal from which a physical variable is derivable which is directly related to the absolute local air humidity (ƒ) in a local nozzle surrounding, wherein the controller ( 250 ) is configured to perform or trigger the performance of at least one of the following steps: changing the bath temperature (TB) of the alloy melt bath ( 11 ), and/or changing the thickness (d) of the nozzle lip gap ( 17 ), and/or changing the distance (Z) between the nozzle lip gap ( 17 ) and the side of the steel flat product ( 100 ), adjusting the flow rate (D) of the gas (G), to keep the target thickness of the layer ( 10 ) to be applied essentially constant.
18 . Device ( 150 ) according to claim 14 , characterized in that it comprises a controller ( 250 ) configured to adjust or trigger the adjustment of one or more of the adjustable parameters depending on the current absolute local air humidity (ƒ).
19 . Device ( 150 ) according to claim 14 , characterized in that it comprises a controller ( 250 ) which is configured to determine a stripping efficiency (AWZ), wherein the stripping efficiency (AWZ) defines a relationship between the current absolute local air humidity (ƒ) and the adjustable parameters and wherein the following condition must be fulfilled to avoid marble formation: ƒ>AWZ.
20 . Device according to claim 18 , characterized in that it comprises a motor or actuator (M) per gas nozzle ( 15 ), which is for control purposes connected to the controller ( 250 ) in such a way that the controller ( 250 ) reacts to a changing absolute local air humidity (ƒ) by reducing the distance (Z) if the current absolute local air humidity (ƒ) is reduced and reacts by increasing the distance (Z) if the current absolute local air humidity (ƒ) is increased.
21 . Device according to claim 18 , characterized in that it comprises a pumping device (P g ) and a control loop per gas nozzle ( 15 ) to automatically adjust the flow rate (D) of the gas (G) in such a way that the target thickness of the layer ( 10 ) remains essentially constant.
22 . Device according to claim 18 , characterized in that it comprises a bath heater ( 30 ) which is for control purposes connected to the controller ( 250 ) in such a way that the controller ( 250 ) reacts to a changing absolute local air humidity (f) by adjusting the bath temperature TB, the bath temperature TB being in the range of 400 degrees Celsius<TB<480 degrees Celsius, preferably in the range of 409 degrees Celsius<TB<473degrees Celsius, and particularly preferably in the range of 420 degrees Celsius<TB<460 degrees Celsius.Join the waitlist — get patent alerts
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