Roll stand for rolling a product, in particular made of metal
View Patent ↗The invention relates to a roll stand for rolling a product, in particular made of metal, comprising a pair of first rollers contacted by a pair of second rollers supporting the first rollers, wherein the first roller and the second rollers have an asymmetrical radius curve (CVC grind) relative to a center plane, wherein the radius curve of the first rollers is represented by a polynomial of the third or fifth order. In order to design the wedging of a second roller supporting a first roller such that optimal operating conditions are set, the invention proposes that the radius curve of the second roller is given by a polynomial of the third or fifth order, wherein special relationships are prescribed for the ratios between the coefficients.
1. A roll stand for rolling a product, comprising a pair of first rolls in contact with a pair of second rolls that support the first rolls, wherein the first rolls and the second rolls have a radius curve (CVC cut) that is asymmetric relative to a center plane, wherein the radius curve of the first rolls satisfies the following equation:
R AW ( x )= a 0 +a 1 ·x+a 2 ·x 2 +a 3 ·x 3
where
R AW (x): radius curve of the first roll
x: coordinate in the longitudinal direction of the barrel with the origin (x=0) in the barrel center
a 0 : actual radius of the first roll
a 1 : optimization parameter (wedge factor)
a 2 , a 3 : coefficients (adjustment range of the CVC system),
wherein the radius curve of the second rolls satisfies the following equation:
R SW ( x )= s 0 +s 1 ·x+s 2 ·x 2 +s 3 ·x 3
where
R SW (x): radius curve of the second roll
x: coordinate in the longitudinal direction of the barrel with the origin (x=0) in the barrel center
s 0 : actual radius of the second roll
s 1 : optimization parameter (wedge factor)
s 2 , s 3 : coefficients (adjustment range of the CVC system)
where the following relation exists between the given variables:
s 1 =f 1 ·[R SW /R AW ·( b 2 contAW −b 2 contSW )· a 3 +b 2 contSW ·s 3 ]
where
b contAW : contact length of the two first rolls
b contSW : contact length between the first and second roll or length of the second roll
f 1 =−1/20 to −6/20,
wherein the wedge factors a 1 and s 1 are optimized to prevent horizontal rotational moments or axial forces,
wherein the first rolls have a CVC contour configuration different from the CVC contour configuration of the second rolls.
2. The roll stand in accordance with claim 1 , wherein the following relation exists between the coefficients of the radius curve of the first rolls:
a 1 =f 1 ·a 3 ·b 2 contAW
where f 1 =−1/20 to −6/20.
3. A roll stand for rolling a product, comprising a pair of first rolls in contact with a pair of second rolls that support the first rolls, wherein the first rolls and the second rolls have a radius curve (CVC cut) that is asymmetric relative to a center plane, wherein the radius curve of the first rolls satisfies the following equation:
R AW ( x )= a 0 +a 1 ·x+a 2 ·x 2 +a 3 ·x 3 +a 4 ·x 4 +a 5 ·x 5
where
R AW (x): radius curve of the first roll
x: coordinate in the longitudinal direction of the barrel
a 0 : actual radius of the first roll
a 1 : optimization parameter (wedge factor)
a 2 to a 5 : coefficients (adjustment range of the CVC system),
wherein the radius curve of the second rolls satisfies the following equation:
R SW ( x )= s 0 +s 1 ·x+s 2 ·x 2 +s 3 ·x 3 +s 4 ·x 4 +s 5 ·x 5
where
R SW (x): radius curve of the second roll
x: coordinate in the longitudinal direction of the barrel
s 0 : actual radius of the second roll
s 1 : optimization parameter (wedge factor)
s 2 to s 5 : coefficients (adjustment range of the CVC system)
where the following relation exists between the given variables:
s 1 =f 1 ·[R SW /R AW ·( b 2 contAW −b 2 contSW )· a 3 +b 2 contSW ·s 3 ]+f 2 [R SW /R AW ·( b 4 contAW −b 4 contSW )· a 5 +b 4 contSW ·s 5 ]
where
b contAW : contact length of the two first rolls
b contSW : contact length between the first and second roll or length of the second roll
f 1 =−1/20 to −6/20
f 2 =0 to −9/112
wherein the wedge factors a 1 and s 1 are optimized to prevent horizontal rotational moments or axial forces,
wherein the first rolls have a CVC contour configuration different from the CVC contour configuration of the second rolls.
4. The roll stand in accordance with claim 3 , wherein the following relation exists between the coefficients of the radius curve of the first rolls:
a 1 =f 1 ·a 3 ·b 2 contAW +f 2 ·a 5 ·b 4 contAW
where
f 1 =−1/20 to −6/20
f 2 =0 to −9/112.
5. The roll stand in accordance with claim 3 , wherein the coefficients a 4 and a 5 of the radius curve of the first rolls are zero.
6. The roll stand in accordance with claim 3 , wherein the coefficients s 4 and s 5 of the radius curve of the second rolls are zero.
7. The roll stand in accordance with claim 1 , wherein the radius curve R AW (x) of the first rolls and/or the radius curve R SW (x) of the second rolls is designed so that tangents that touch an end diameter and a convex part of the work roll and a tangents that touch the other end diameter and a concave part of the work roll are parallel to each other and are inclined to the roll axes by a wedge angle.
8. The roll stand in accordance with claim 1 , wherein the first rolls are work rolls and the second rolls are backup rolls.
9. The roll stand in accordance with claim 1 , wherein the roll stand is a six-high stand, the first rolls are intermediate rolls, and the second rolls are backup rolls.
10. The roll stand in accordance with claim 1 , including several rolls, wherein a given linear component, a contact length, and a diameter of a corresponding adjacent roll are taken into consideration in determining the coefficients.
11. The roll stand in accordance with claim 3 , wherein the radius curve R AW (x) of the first rolls and/or the radius curve R SW (x) of the second rolls is designed so that tangents that touch an end diameter and a convex part of the work roll and a tangents that touch the other end diameter and a concave part of the work roll are parallel to each other and are inclined to the roll axes by a wedge angle.
12. The roll stand in accordance with claim 3 , wherein the first rolls are work rolls and the second rolls are backup rolls.
13. The roll stand in accordance with claim 3 , wherein the roll stand is a six-high stand, the first rolls are intermediate rolls, and the second rolls are backup rolls.
14. The roll stand in accordance with claim 3 , including several rolls, wherein a given linear component, a contact length, and a diameter of a corresponding adjacent roll are taken into consideration in determining the coefficients.