Ultra short continuous annealing of steel strip
This project aims at evaluating the potentialities of compact annealing which associates technologies of rapid heating and rapid cooling. Such a concept is a way to develop resistance steel grades. Various heating technologies (based on induction and gas jet heaters) were investigated. Their characteristics and efficiencies were compared. Off-line tests were carried out to assess the performance of impinging burners on mild and stainless steel grades. Thermal flows at steel level at least 360 kW/m2 were calculated in the flame impact. It corresponds to an interesting increase of heating rates compared to conventional industrial DFF and significant reductions of furnace length are expected from simulations. Scale at steel surface is compatible with pickling and coating deposition. A compact annealing line was built on the existing CRM pilot line by modification of the heating section: a longitudinal inductor was implemented at the output of the existing DFF and the resistances of electrical furnaces were boosted. Various cooling configurations can be used. They can associate a slow cooling equipment (Hot Water Quenching) with rapid cooling equipment (Turbulent Water Immersed Cooling Equipment) which can be located at the input or at the output of the water tank. Besides, quench by dipping into a hot-dip galvanised tank can be realised. The concept of compact annealing was assessed on mild and Dual Phase steels. It gave the mechanical properties expected and the surface characterisation showed scales compatible with further coatings. The flatness was also analysed and mainly depends on rapid cooling in TWICE.
Bibliographic Reference: EUR 22015 EN (2006), 132 pp. Euro: 25
Availability: Katalogue Number: KI-NA-22015-EN-S The paper version can be ordered online and the PDF version downloaded at: http://bookshop.europa.eu
ISBN: ISBN: 92-79-01677-6
Record Number: 200618697 / Last updated on: 2006-09-14
Original language: en
Available languages: en