January 26, 2014

High Tickness Cut-to-Length Lines from Fagor Arrasate

In recent years, high thickness cut-to-length lines are having continuous changes, adapting to the constant evolution in steel and looking ahead to future trends that the market may demand

Fagor Arrasate event: High Tickness Cut-to-Length Lines from Fagor Arrasate

The main function of this type of lines  is to flatten and cut the strip from a coil and to stack and pack the obtained formats. The line must achieve this by following a series of specifications for which it was designed.

The specifications that are currently requested for high thickness cut-to-length lines include the following:

  • The maximum strip width for this type of line is approximately 2200 mm, but it could reach up to 2800 mm in special cases.
  • Maximum thickness is up to 25 mm for steels up to 900 Mpa tensile strength. Furthermore, the line can process UHSS (Ultra High Strength Steel) because the high tensile strength of these steels (up to 1600 Mpa) is compensated by the less thick size.
  • The minimum thickness that can be processed is limited by the diameter of the smallest leveller rolls and the properties of the material being processed. On average it is approximately 4 mm.
  • Maximum processing speed may range between 20 and 70 m/min depending on the thickness and the yield strength of the strip.
  • Speed does have a strong impact in the production data of these types of installations. The pack of blanks is obtained in just a few minutes. In fact, the area where it is important to increase capacity is stacking and packaging.
  • Blanks can reach a maximum length of up to 20 m, or longer.
  • Flatness less than 5 l units is guaranteed for maximum resistance materials.
  • The cut burr may even be less than 5% of the thickness of the plate to be cut.
  • The blanks produced must be free of internal stress.
  • Maximum production may be over 600.000 Tm/year, depending on the thickness and size of the blanks.

Fagor Arrasate has been researching and developing new technologies for processing and obtaining blanks free of internal stress.

This type of line must incorporate the most up-to-date and complete safety measures to avoid work risks, such us: loading cars pit cover, protective guards on all machines, perimeter line enclosure with electronic locking system doors, photoelectric barriers, emergency stop buttons on all control panels and interlocking devices on all machines for maintenance tasks. In addition, all dangerous areas must be clearly indicated with adds that inform operators of any risks, as well as the necessary protection measures.

This type of line can produce high levels of sound pollution and this is another factor that must be taken into account. Fagor Arrasate  recommends placing at least the hydraulic group and stacker into cabins to reduce the effects of atmospheric and sound pollution. Nevertheless the best solution is to install a cabin around most of the cutting line. Machines must be extremely rigid with a simple design so as to assist with maintenance. Deflection must be at a minimum in critical machines such as the straightener and levellers.
It is recommended that brushing and cleaning equipment is installed in the line to eliminate the calamine and dust detached from the metal sheet while it is in the straightener and leveller, as these measures reduce problems caused by this type of dirt in the installation. The motor-drives installed in the machines must be optimized for the line to perform at its best and be as efficient as possible to reduce energy consumption.

Furthermore, the machine should have a co-generation system that takes advantage of the energy generated by the motors when they operate as brakes. The energy generated can be distributed to other parts of the installation or factory.
Automation of the processes increases productivity and reduces work risks. Processes such as automatic coil loading, automatic shear clearance regulation, pre-setting the position of the leveller rollers and changing the leveller cassette must be fast and automatic.

There should be a human-machine interface (HMI) with easy to use screens that can be used to control all operation in an intuitive way of the paremeters of, maintenance, diagnosis and tele-assistance in remote mode.