Slovenian steelmaker Acroni has contracted SMS Siemag to supply a heat treatment line and revamp a stainless steel annealing and pickling line. Commissioning is planned for 2016 at the company’s Jesenica plant.
Where heat treatment is concerned, SMS Siemag will install its newly developed MultiFlex Quench system, which is claimed to offer ‘an outstandingly high degree of flexibility’ and high cooling efficiencies during the heat treatment of heavy plate.
Acroni is a highly specialised niche supplier of stainless steel plate and strip, tool steels, abrasion-resistant steels and HSLA grades. The new heat treatment line will enable the company to expand its product portfolio.
The new line is designed for plates with thicknesses ranging from three to 100mm and the range of materials includes high-strength carbon steels, stainless and tool steels and a range of special steels.
SMS Siemag will supply a roller-hearth furnace for hardening and normalising, a MultiFlex quench system and a roller-hearth furnace for tempering, as well as all auxiliary facilities, including plate conveying equipment and all the required systems for water supply and treatment and automation systems.
The hardening furnace will be equipped with two chambers and the plates will be annealed in a nitrogen-based inert gas atmosphere. Heating up to 1,100 deg C will be carried out indirectly using radiant heating tubes.
The MultiFlex quench system is claimed to offer a high degree of flexibility as it offers a wide range of cooling rates. Squeezer rolls ensure plate flatness, even at high cooling rates, says SMS-Siemag. After quenching, plates can be tempered in an open-heated roller-hearth furnace at temperatures between 400 C and 800 C.
The modernisation of the annealing and pickling line is to reduce the burden on the environment during the manufacture of strips made of non-grain oriented silicon grades (NGO up to 2.4% Si content).
“To achieve this, the chemical pickling line will be replaced by a purely mechanical descaling system in combination with a brushing action,” SMS-Siemag explained. “Dispensing with chemical descaling and the associated acid regeneration by the spray roaster process will make the Acroni works much more environment-friendly.”