Aceralia Spain - m/cing for new screwdown capsules

Fitting new hydraulic screwdown capsules to the four stands of a tandem intermediate/finishing mill at Aceralia(Avilés) steel company, Asturius, Spain has enabled the steel producer to substantially improve product qualityand thickness tolerance. So that the new capsules could be fitted Metalock Engineering in-situ remachinedeight bores on the four stands using four of their purpose-designed boring machines to ensure the work wascompleted as quickly as possible.

Based in Coventry, with facilities in strategic locations throughout the UK, Metalock was selected to carry out there-boring work by VAI Cosim following good reports on earlier work from their French sister company VAI Clecimand the VAI Group itself. Aceralia, which produces over a million tonnes of steel product annually, needed to getthe machining work done as quickly as possible so that the new load cells could be fitted and the mill returned tooperation with minimum downtime. Using four boring machines, Metalock was able to complete the machiningtask in 9 days, working 24 hours a day with a 14-man team. In all over 11 tonnes of metal was removed.

The actual work involved enlarging the eight bores on the four Blaw-Knox mill housings to accept the newcapsules from 711.5 mm to 950 mm diameter to a depth of 565 mm from the previous 558 mm finishing with a50mm radius at the end of each bore. Special single-point turning devices were manufactured to generate theradius and produce the required surface finish.

The tandem mill at Aceralia can be used as an intermediate mill or a finishing mill depending upon productionschedules. As an intermediate it would reduce slabs down prior to tempering. As a finishing mill strip productpasses through to a tinning line and be capable of producing strip up to 1524 mm wide good quality control andthickness tolerance over the full width is essential. The new screwdown system is enabling these parameters tobe more constantly achieved than previously. As screwdown pressure has now been increased with the newequipment Aceralia are planning to produce harder steels on this mill in due course.

A spokesperson for VAI Cosim told Metalock that they were very impressed by the professionalism and dedica-tion of the team to the job in hand. The final result was better than expected and the work was carried out wellwithin budget and to time.

Metalock bored out four stands of a tandemintermediate/finishing mill so that new hydraulicscrewdown capsules could be fitted. Four purpose-designed boring machines were usedsimultaneously to speed the in-situ process.