In February 2015 Acciaierie Bertoli Safau (ABS) contracted Italian steel technology specialist Danieli Olivotto Ferrè to provide engineering, manufacturing and installation of a new bar heat treatment at the steelmaker’s Cargnacco plant.
The Cargnacco facility anneals, tempers, normalises and stress relieves 6,000 tonnes/month of a wide range of bar profiles, from smaller bar bundles (25 mm) up to single 600 mm diameter bars. Lengths are variable ranging from 3 m to 14 m while all steel grades are covered, from low carbon to high alloy.
The line consists of six bases and two direct firing lift-off type furnaces that function by means of burners fed with natural gas; two lift-off cooling hoods incorporating a cooling system; a crane for lift-off handling; a waste gas exhaust system including six damper valves and ducts to one common natural draught chimney; an electrical power distribution system and a Level 1 control system supplied by Danieli Automation.
According to Danieli, important technological improvements were made including low fuel consumption and reduced emissions. Improved chamber temperature uniformity in order to achieve Furnace Certification AMS 2750 was also implemented into the plant design.
The modular batch design of the plant leaves room for future expansion and includes high efficiency and state-of-the-art combustion technology. User-friendly loading procedures and bar positioning, easy access for inspection and maintenance also give rise to a safer plant.
Danieli reports that annealing and normalising cycles demonstrated a 20-30 % decrease in gas consumption compared with previous generation furnaces (at the very start of the commissioning phase).