SIROLLCIS CM Solutions for cold rolling mills - Industry - Siemens

Process automation solution
Complete process control at every level
Main pulpit, voestalpine Stahl, Linz, Austria
Sophisticated automation concept
Technological controls and process
models are the core of any sophisticated
automation concept with the goal of
maximizing utilization of the mechanical,
hydraulic, and other positioning
elements. The control concepts have
evolved with the increasing performance
of the equipment – from simple analog PI
controllers to highly complex and
interlinked control systems. These
controls and process models are an
integral part of SIROLL CIS CM. The value of
the SIROLL CIS CM concept is visible in the
rolled strip: improved gauge tolerances,
less off-gauge material, perfect flatness
to meet growing demands worldwide.
Setup and rolling directives
The core of the automation system is the
set-point calculation with the aid of the
process models and the rolling directives.
The advantages of online process models
in combination with neural networks for
20
adaptation in the process automation
system include the more accurate setpoints
and easy matching of new
materials. Siemens VAI process
automation also optimizes product
quality by permitting a very high degree
of flexibility in the parameterization of
rolling directives. Rolling directives are
derived automatically from specific
material characteristics.
The process rolling models
The mechanical rolling model
Rolling force, rolling torque and forward
slip are among the technological rolling
parameters governed by the interaction
between elastic flattening of the work
rolls and vertical pressure distribution
along the strip/work-roll interface. The
differential equations associated with this
interaction are resolved within the
mechanical model. Siemens VAI opted to
develop a fast online model based on
Fleck/Johnson’s noncircular arc roll-gap
theory meeting higher demands.
The yield-stress and friction model
The principal input variables for the
mechanical model are friction and
material hardness. The yield-stress model
describes the material’s yield-stress as it
relates to chemical composition,
incoming hardness depending on hot
rolling history, and hardening caused by
cold rolling deformation.
The friction model describes the friction
between the strip and the surface of the
roll, taking into account all relevant
factors such as lubrication, roll-surface
roughness and strip speed.
The bending model
A bending model with online capability is
the central function for calculating the
roll-gap profile. Flattening between work
roll and supporting rolls, roll bend and
roll contour are all taken into account in
calculating roll-gap profile.
Siemens VAI uses a highly accurate FEM
method to verify the results of the fast
online model.