"On the blocks" for the rebirth of the Caleotto wire rod mill

Caleotto and SMS group have joined forces to bring the production back at peak output. Therefore a new MEERdrive^®PLUS block, a multiline loop concept and a MEERgauge^® system have been installed in the existing wire rod line.

The original plant design was capable of producing quality wire rod from 5.5 to 17 millimeter diameter, starting from 140 and 160 millimeter billets with a length of 9,500 millimeters and weighing up to 1,850 kilograms. 170 millimeter billets with a weight of 2,300 kilograms could also be rolled to obtain heavier coils. Steel grades ranged from low, medium to high carbon steel for all applications, case hardening, cold heading, quenching & tempering steel, spring steel, boron steel, and welding wire produced at rates of 70 tons per hour. With the mill upgraded Caleotto will now be able to produce 300,000 tons per year of wire rod from special steel. Final products (in some grades and diameters) can also be produced with a thermomechanical rolling process at temperatures between 750 °C – 800 °C.

SMS group has been a pioneer in blocks with individually driven stands and combined the market´s demand for a 4-pass wire rod block with an individually driven-stand MEERdrive^® block. The result was the MEERdrive^®PLUS, a 4-pass sizing block that is capable of rolling and finishing wire rod within the 4.5 millimeter to 26 millimeter range. With this wire rod sizing block, it will be possible to achieve tolerances close to 0.05 millimeters and an exceptional ovality thanks to the ORRR (oval round round round) pass sequence.

A typical application of the MEERdrive^®PLUS is to install it after an 8 or10 pass traditional finishing block as featured in the Caleotto rolling mill. The technological distances and the water boxes required before and after the wire rod sizing block depend on the relevant steel grades and their end use.

All sizes are finished on the MEERdrive^®PLUS, using the 8-pass block as a feeder of small sizes from 4.5 to 12.5 millimeters, and the intermediate mill for the remaining sizes up to 26 millimeters. With this solution, changing times are reduced considerably and the mill utilization time is significantly improved. If the produced mix of sizes is extended especially, a quick-changing device for changing all 4 stands simultaneously is also possible.

The inline MEERgauge^® measuring system, which is based on laser light- section technology installed after the MEERdrive^®PLUS can measure up to 99 % of the bar surface (depending on the speed). The system uses four sensors and has a scanning rate of up to 15,000 scans per second. A true-shape cross-section is created from up to 400 synchronous measuring points in a shared coordinate system, and is then displayed with maximum precision. Unlike with conventional systems, the true shape of the contour can be represented precisely. With no moving or oscillating parts, the system requires almost no maintenance.

All fields of steel production share the goal of attaining the best possible mill availability even with changing market conditions. With mills producing quality steel in particular, small lot sizes are required. This in turn necessitates frequent mill changes with the associated increase in downtimes. In view of this, SMS group has developed the multiline loop concept that enables together with a 4-stand sizing block a mill utilization rate in excess of 90 % for the production of quality wire rod with small lot sizes. Mill owners can therefore respond quickly to market needs and inventories can be reduced.

Using the 8-stand block and the 4-stand MEERdrive^®PLUS block in the finishing part of the mill, single family rolling is utilized from stand 1 up to the block exit. The complete finished product size range from 4.5 to 26 millimeters is rolled on the MEERdrive^®PLUS. Quick changing facilities are available in two different options. The most economical solution is a quick roll change that allows a complete size change within 15 to 20 minutes. The other possibility would be to change the entire 4-stand MEERdrive^®PLUS within five minutes requiring the installation of an additional unit. Tolerances are within ± 0.1 millimeters for the complete size range. The design speed is 120 meters per second with new dressed rolls. In addition to the above, there is the multiline loop in combination with the 8-stand block and the 4-stand MEERdrive^®PLUS, offering advantages that cannot be achieved with any other mill concept.

Installed at the end of the existing controlled cooling conveyor is a new curved portion of a state-of-the-art most modern Ring Distribution System (RDS), the purpose of which is to properly distribute the windings properly to ensure a compact coil formation. The RDS is followed by a coil lowering station, which smoothly lowers the compact coils onto a vertical pallet system. Finally, the pallets hand over the coils to the installed C-hook system for subsequent trimming and compacting procedure. It is designed to offer special protection to the finished wire rod material and is also adapted to the high-quality finished product.

The MEERdrive^®PLUS offers plant owners a solid opportunity of producing supreme wire rod in terms of dimensional tolerances and surface quality, but it is not only the machine alone that does the “right job”. It is a combination of equipment that provides Caleotto with a range of new opportunities, from the rebirth of its mill up to the consolidation of its position in the market.

Final products manufactured at the Caleotto plant are becoming much more attractive for drawing line operators and forging producers, reducing to zero spread cold heading operation. End users prefer products with better surface and dimensional tolerances, with the aim of avoiding stoppages in the drawing lines due to starting material defects, which results in an immediate payback from the market, where only selected products are bought.