Method for manufacturing flexible rolling of metal strips

Abstract

A method for manufacturing flexible rolling of metal strips, in which a metal strip with pre-definable material thickness is guided through a mill stand by at least two operating steps, which includes several rolls, the metallic strip is during the rolling operation set to lead through a roll gap, where a curve bending line is steered to achieve a defined profile.

Claims

1. A manufacturing method for flexible rolling of metal strips, comprising: guiding a metal strip with a pre-definable material thickness through a mill stand containing several rolls, wherein the metal strip is set to lead through a roll gap during the rolling operation, where bending of the work rolls is steered to achieve a defined profile with different thicknesses over a length of the metal strip, based on two operating steps of a rolling operation; a first step of the two operating steps is a learning phase based on manually controlling and storing parameter values of hydraulic adjustment and flatness actuators during rolling of the defined profile, during which thickness and flatness data of the strip are collected; wherein the flatness actuator parameters are controlled to steer bending of the work rolls to achieve the defined profile; and a second step of the two operating steps is repeating a program loop for flexible rolling having starting values from the first step for providing a strip having the defined profile repeatedly formed over the length of the strip; wherein the starting values from the first step include the thickness and flatness data collected during the first step and the parameter values of the hydraulic adjustment and flatness actuators stored during the first step.

2. The method according to claim 1, wherein the defined profile comprises different thicknesses over a length of the metal strip.

3. The method according to claim 1, wherein the defined profile comprises at least two thicknesses over a length of the metal strip.

4. The method according to claim 1, wherein the metal strip comprises a width range of 400 to 1600 mm.

5. The method according to claim 1, further comprising work roll bending in dependence on the rolling force to influence flatness of the metal strips.

6. The method according to claim 1, further comprising setting three existing systems to measure flatness of the metal strip.

7. The method according to claim 1 wherein the flatness data is collected by a contactless flatness measuring system.

8. The method according to claim 1, wherein a width range of the metal strip is 400 to 1600 mm.

Description

(1) An exemplary embodiment of the object of the invention is illustrated in the drawings and described in greater detail below. In these drawings:

(2) FIG. 1 shows a schematic diagram of rolling stands for profiling a metal strip and the geometry definition of the flexible rolled strip.

(3) FIG. 2 shows a schematic diagram of a metal strip that is wound up on a coil with subsequent cold deformation and another coiling operation and measuring of the plateau to control the process.

(4) FIG. 1 shows a schematic diagram of the rolling stands. A metal strip is produced by a Sendzimir mill in a width range of 400 and 1600 mm which is recurring above the length of the strip. The concept of the invention is especially focused on flexible rolling. The existing standard process is focused on a consistent thickness above the strip length in close tolerance limits. In contrast to that, the flexible rolling is characterized by different thicknesses in short distances but none the less in close tolerance limits. One profile, which is normally between 500 and 2000 mm long repeats continuously above the length of the strip. This process requires continuously highly dynamic changes of the cold rolling mill. The V adjustment increases for example by factor 3.5 because of the spring rate of the mill and this is multiplied by 14-30, preferable 18-26 is the velocity of the hydraulic cylinder. Typical numbers for velocity of the hydraulic cylinder are a range between 0.17 mm/s and 5.83 mm/s, where 0.17 mm/s (rolling gap) 13.09 mm/s (hydraulic cylinder) and 5.83 mm/s (rolling gap) 448.91 mm/s (hydraulic cylinder). In a FIG. 1 is a sketch of a geometry definition after rolling a metallic strip. The steering phase is characterized by the immediate adjustment of the roll gap (edge), so that the transition between two thicknesses will be achieved. In FIG. 1 during the phase of controlling the thickness is controlled in minimum one loop (plateau). During the controlled phase it is possible to influence the flatness actuators manually. The flatness gets influenced by the bending of the work rolls in a defined relation. The flatness can be measured for example by an optical laser system, a stressometer roll or a SI-Flat System. The process of the roll gap adjustment is steered by switching to a controlled phase during the rolling of the plateau. The use of a following plateau which is already rolled to control the plateau between the working rolls. Furthermore two existing systems are to measure the flatness of the strip. A contactless SI-Flat System can be used, which is based on the evaluation of the local amplitude of oscillation.

(5) FIG. 2 shows the number of rolls and the actuators (hydraulic adjustment, crowns, first intermediates) to influence the thickness and flatness. In addition the control engineering takes the characteristic of the mill type into account and permits faster regulation of the process. Furthermore the specific properties of every metal strip are considered because the bending of the work roll is not depending on the rolling gap. Furthermore the figure shows a defined profile with different thicknesses over the length of the strip. The bending is necessary for the process. By using a 20 roller instead of duo- and quarto-mill the final result will be a flat and higher strength strip. The bending of the working rolls depends on the needed working force to roll a specific grade. The steering of the work roll bending is based on the reference variables of the flatness measurement system, which are determined during the learning phase.