Start ups: Burns Harbor

ArcelorMittal plate production in ArcelorMittal’s Burns Harbor work, Indiana, USA has just re-started the quenching and/or tempering facility after a major re-vamp of the heat-treat facility.

ArcelorMittal plate production in ArcelorMittal’s Burns Harbor work, Indiana, USA has just re-started the quenching and/or tempering facility after a major re-vamp of the heat-treat facility. The line has been equipped with a new state-of-the-art 7,700 Metric ton plate leveller from JP SteelPlantech Co., the strongest roll leveler in the world to date. A Shapeline Flatness gauge has been installed down-stream from the leveler, which is used to adjust the leveller and verify that the plates meet the requirements.

The leveller, as well as the flatness gauge, can handle hot and cold plates up to 1400 MPa yield stress or up to 100 mm thickness. The Plantech 4-th generation roller plate leveller has the capability of compensation of deflections in the mechanical structure through a set of hydraulic cylinders by means of on-line gap measurement and on-line pressure measurement. The gap inside the leveller can be kept constant, vertical deflection is compensated for as well as lateral deflections and compression deflections. Due to having this capability, the 4th generation is seen as a plate leveller having an infinite rigidity control function. This leads to a much better levelling capability since the levelling becomes less dependent on levelling fluctuations and hence a flatter plate is produced. The infinite rigidity also deals with plates with high thickness, high yield strength and varying yield strength. Residual stresses are also reduced since the levelling becomes more uniform. A further advantage is that the levelling force can be increased due to more evenly distributed force. The Burns Harbor leveller has a levelling force of 7,700 Metric Tons.

A direct effect of the 4th generation leveller is that the number of levelling passes can be reduced. This increases the throughput of the line and reduces the need for additional levelling lines. As a consequence, the number of plates can be increased, which puts higher requirements on the flatness measurement. Automated, high-capacity measurement is a necessity, which has been realised through the Shapeline flatness measurement gauge.

The target for ArcelorMittal is to produce ¼ of ASTM in terms of flatness, which will be verified and documented by the Shapeline system for each individual plate and hence, plate flatness data can be retrieved at any time for any plate. Flatness data from the gauge can also be used to tune and improve the performance of the Plantech leveller.