Finspong Sweden - mill window m/cing

Completion of a series of complex in-situ machining operations by Metalock Engineering UK for SAPA HeatTransfer at Finspong in Sweden has meant that their 1500mm wide hot mill is now capable of rolling slabs that are60% larger than previously. It can now cope with 10-tonne billets instead of the 6 tonnes the mill was designed forand, enable a significant increase in output. It is quicker to roll a 10-slab than two of the smaller ones.

To permit these increases the mill had to be significantly upgraded to accept new equipment and in particular, themill window height extended to accommodate the thicker slabs. Work was also needed to allow new screwsets tobe installed.

Project managers for the job were VAI Industries(UK) who selected Metalock to undertake the in-situ machiningwork due to previous experience of working with them on several other projects. The alternative of removing thehousings for modification was unacceptable because of the time that it would take.

The Metalock team, made up of engineers from Coventry and colleagues from Sweden, machined outside andinside faces on the mill windows for new equipment to be fitted. Having upgraded steel rolling mills all over theworld Metalock used their specially designed in-situ machining bed equipped with a dual milling head. This allowsboth sides of the mill window to be machined simultaneously, substantially reducing the time taken on eachhousing.

External faces of the operator and drive side housings were machined and the wear plate height increased by200mm on all four posts. In addition, 60mm deep pockets were milled on the inside faces of the housing toaccommodate new components.

To extend the mill window height by 30mm and retain large stress raising radiuses in the corners Metalockdesigned and built a separate milling machine that could be used while the sides of the mill window were beingmilled. To increase the diameter and deepen the bores for the new screwdown equipment, Metalock used apurpose designed boring attachment and another for drilling and tapping new holes for the screwdowns.

To extend the mill window height andretain the large stress relieving radii in thecorners, Metalock designed and built aseparate milling machine that could beused while the sides of the mill were beingmachined.