Products & Services » Rolling » Profile and Flatness » Technological audit

Technological audit of the profile and flatness of strips and plates

We will solve your problems with achieving desired crown of strips or plates, or problems with flatness of rolled production performing an audit of your rolling technology.

Audit of technology = analysis of existing technological conditions of rolling, making computer simulations, parametric studies or process measurements resulting in proposals of technological measures to achieve the desired profile or to suppress unwanted waviness of hot or cold rolled flat production.

Audit of technology

The audit of technology is based on actuators that are on the rolling mill available. Generally we can take into account effects of the following actuators:

  • »optimization of bending forces
  • »modification of grinding of rolls
  • »axial shifting of rolls
  • »section cooling of work rolls
  • »modification of pass schedule

Bending forces optimal sequence specification represents the determination of such a crown progression in particular passes which would cause minimum strip longitudinal stress (not get over the flatness criteria).

Hot wide strip profile and flatness

Calculated strip profile for various bending forces

Flatness criterion

Flatness criterion Hot wide strip profile and flatness

Crown progression in individual passes and a subspace ensuring the strip flatness

Through the work and backup rolls proper grinding the strip flatness can be achieved as well as bending forces extending in the allowed range during the whole work rolls campaign. While rolling a strip with a stable width (a situation usual at cold mills), through a special grinding it can be achieved still better flatness than on usual rolls with a parabolic profile.

Typical cold strip profile with an abrupt thickness reduction on its edges is presented on the following picture. This phenomenon implicates often occurence of edge waviness.

Typical strip cross profile (with an abrupt thickness reduction on its edges)

Typical strip cross profile (with an abrupt thickness reduction on its edges)

This feature can be prevented with a help of a special grinding shape – see the following figure

Work roll upper surface unloaded profile

Work roll upper surface unloaded profile (parabolic grinding, special grinding 1 and special grinding 2)

References