MILL ROLLS CAPABLE OF ROLLING LONG KILOMETERS FOR ESP PRODUCTION LINE

• US 20190308232A1
• Filed: 06/13/2017
• Published: 10/10/2019
• Est. Priority Date: 06/15/2016
• Status: Active Grant

• Current Assignee: Arvedi Steel Engineering S.p.a.
• Original Assignee: Primetals Technologies Austria Gmbh (Mitsubishi Heavy Industries, Ltd.)
• Inventors: ARVEDI, Giovanni, LENGAUER, Thomas
• Granted Patent: US 11,059,083 B2
• Time in Patent Office: Days
• CPC Class Codes: B21B 1/463 in a continuous process, i.e. the cast not being cut before rolling
• CPC Class Codes: B21B 2027/022 Rolls having tapered ends
• CPC Class Codes: B21B 2267/02 Roll dimensions
• CPC Class Codes: B21B 2267/18 Roll crown; roll profile
• CPC Class Codes: B21B 2267/24 Roll wear
• CPC Class Codes: B21B 27/02 Shape or construction of rolls for rolling metal of indefinite length in repetitive shapes specially designed for the manufacture of particular objects B21H8/02 ; B21B27/005 takes precedence
• CPC Class Codes: B21B 27/021 Rolls for sheets or strips

Abstract

Mill rolls capable of rolling long kilometers used for ESP production line and a method for rolling long kilometers using the mill rolls. The mill rolls include rolls (3, 4), a bearing box (2) and a roll shifting hydraulic cylinder (1), wherein the middle portion of the surface of the roll sinks inwards, one end of the rolls is frustum-shaped, smaller and smaller outwards, so that the roll surface forms a compensation ramp, and the other end of the rolls is cylindrical. The upper roll (3) and the lower roll (4) have the same roll profile and are positioned in the opposite direction. The mill rolls are characterized by reduced runaway of the rolled product and a longer service life.

Claims

1. Mill rolls capable of rolling long kilometers of a rolled product in a production line of a rolling mill,

the rolling mill comprising:

a first mill roll and a second mill roll oriented parallel to each other, each roll rotatable around a respective roll axis, and the rolls including respective roll surfaces positioned to roll a rolled product between the first and second rolls and to thereby define a shape for the rolled product;

each of the rolls has ends;

a rotation bearing at at least one of the ends of each of the first and second rolls;

a roll axial shifting device connected to each roll in a position to enable each roll to rotate around the axis of each roll, and the respective roll axial shifting devices are configured and operable to shift each roll in a respective axial direction of the roll;

each of the mill rolls comprising a middle portion of the surface of the roll and the middle portion sinks radially inwardly in shape;

one end of each of the rolls is frustum-shaped, of smaller radius axially outward on the roll;

the other end of each of the rolls is cylindrical; and

the first and second rolls each have a same roll profile over their length and are positioned respectively such that the ends of the rolls face in opposite directions.

2. The mill rolls of claim 1, wherein a roll profile of the middle portion of the roll surface of each of the rolls sinks radially inward and is curved in a cosine curve or a polynomial roll profile curve.

3. The mill rolls of claim 2, wherein the polynomial roll profile curve is a parabolic curve.

4. The mill rolls of claim 1, wherein a slope of the frustum of each roll=wear (Δ

r)/roll shifting value (s).

5. The mill rolls of claim 4, wherein the slope of the frustum is not more than 0.01.

6. The mill rolls of claim 1, wherein the rotation bearing for at least one of the rolls is connected to a respective one of a roll radial shifting device and each roll radial shifting device is configured for adjusting the respective roll in radial directions.

7. The mill rolls according to claim 6, further comprising a thickness gauge for measuring the thickness of the rolled product;

a controller to which the thickness gauge is connected, wherein the controller is configured to determine a thickness error (e), that is a difference between a target value of the thickness of the rolled product and a measured thickness of the rolled product; and

the controller is connected to the roll axial shifting devices for causing axial shifting so that the rolls move in respective opposite axial directions in accordance to the thickness error (e) of the rolled product.

8. The mill rolls of claim 6, further comprising:

a wear monitor configured for determining wear Δ

r of the first roll and the second roll during rolling, and taking into account rolling parameters including rolling force F, temperature, rolling speed (rev), rolling time, and material of the rolling stock; and

the wear monitor is connected to the controller, and the controller is connected to the roll axial shifting devices for causing axial shifting so that the rolls move in respective opposite axial directions in accordance to the wear (Δ

r).

9. The mill rolls of claim 7, wherein the controller is connected to the roll radial adjusting cylinders for at least one of the rolls for adjusting the at least one roll in a radial direction in accordance with at least one of a thickness error (e) and wear (Δ

r).

11. A method for rolling long kilometers of rolled product using the mill rolls according to claim 1, the method comprising:

to compensate a wear (Δ

r) of the first roll and the second roll, shifting the first roll in a first axial direction a distance corresponding to a roll shifting value (s) by means of a roll axial shifting device connected with the first roll; and

shifting the second roll in a second axial direction by the same distance by means of a roll shifting cylinder connected with the second roll, wherein the first axial direction is opposite to the second axial direction.

12. A method for rolling long kilometers according to claim 11, wherein during the rolling, the axial distance that the first roll and the second roll are shifted is increased over time in a steady or an unsteady manner.

13. A method for rolling long kilometers according to claim 11, further comprising lowering the first roll in a radial direction by a roll adjusting cylinder.

14. A method for rolling long kilometers according to claim 13, wherein while a radial position of the second roll is kept constant, lowering the first roll in a radial direction by a distance that corresponds to a sum of wear (Δ

r) in a radial direction of both of the first roll and the second roll.

15. A method for rolling long kilometers according to claim 13, further comprising lowering the first roll by a distance that corresponds to wear (Δ

r) of the first roll in the radial direction; and

raising the second roll by a radial distance that corresponds to the wear (Δ

r) of the second roll in the radial direction.

16. A method for rolling long kilometers according to claim 15, wherein the distance over which the first roll is lowered corresponds to the distance over which the second roll is raised.

17. A method for rolling long kilometers according to claim 11, wherein:

the first roll is shifted in the first axial direction a distance corresponding to a roll shifting value (s) by means of the respective roll axial shifting device connected with the first roll, and the first roll is lowered by roll radial adjusting devices in a radial direction; and

wherein the second roll is shifted in the second axial direction over the same distance by means of the roll axial shifting device connected with the second roll and the second roll is raised in the radial direction by the roll radial adjusting, device wherein the distance that the first roll is lowered radially corresponds to the distance that the second roll is raised radially.

18. A method for rolling long kilometers according to claim 11, wherein a maximum axial shifting distance of the first roll and the second roll is between 300 mm and 600 mm.

19. A method for rolling long kilometers in a rolling mill according to claim 11, further comprising measuring a thickness of the rolled product during rolling, and calculating the thickness error (e), which is a difference between a target value of the thickness of the rolled product and the measured thickness of the rolled product during the rolling;

and

shifting the first roll and the second roll in opposite axial directions as a function of the thickness error (e).

20. A method for rolling long kilometers according to claim 11, wherein the wear (Δ

r) of the first roll and the second roll are determined during rolling, taking into account rolling parameters including rolling force F, temperature, rolling speed rev, rolling time, material of the rolling stock; and

shifting the first roll and the second roll in opposite axial directions as a function of the wear (Δ

r).

21. A method for rolling long kilometers according to claim 11,

wherein the axial roll shifting value (s) of the first roll and the second roll are shifted as s=Δ

r*L/R, wherein L is the length of the frustum-shaped end of each of the rolls, R is the radial extension of the frustum-shaped end of each of the rolls, and Δ

r is the wear.

22. The mill rolls according to claim 1, wherein the first roll is positioned during use of the rolls as an upper roll and the second roll is positioned during use of the rolls as a lower roll below the first roll.

23. The mill rolls according to claim 1, wherein the roll axial shifting devices are hydraulic cylinders.

24. The mill rolls according to claim 6, wherein the roll radial adjusting devices are hydraulic cylinders.

10. (canceled)