The overall aim of this REFCS project was to develop the cooling technology applicable to the new innovative Advanced High Strength Steel (AHSS) grades such as DP, TRIP, CP, MART and selected other steels enabling the most effective controlling of their microstructure and property distribution.
Three types of laminar flow cooling headers facilitating edge-masking feature and having differing engineering mechanisms, which also permit selection of cooling ranges in the transverse direction as well as cooling rates that can be adjusted on both sides of the strip symmetrically (WACOOLs 1 & 2) or asymmetrically (WACOOL 3), have been developed, implemented and evaluated. New cooling strategies have been investigated especially for the finishing mill and run-out tables, in order to improve the strip shape and the mechanical and metallurgical properties of steel. To establish a comprehensive coverage of strip cooling and production of AHSS grades an investigation of the strip shape changes along the cooling path between FM and down coiler have been undertaken.
The ultimate objectives of the project are listed below:
- develop advanced instruments, methods and techniques for the industrial production of the new AHSS grades;
- minimise water consumption needed for hot-rolled strip cooling in order to be more environmental friendly by reducing consumption of energy and water resources;
- development of innovative width adaptable cooling systems;
- adaptation of the laminar flow region to the width of the strips with different adjustment mechanisms;
- optimisation of the water distribution for additional cooling headers, i.e., conversion from transversal to longitudinal water cooling;
- extension of technological process windows by online adjustment of cooling patterns using interstand cooling systems.
- mathematical modelling of microstructural evolution during cooling of strips by combining theoretical and experimental investigations;
- knowledge on the hot rolled strip shape changes during cooling to enable an improved flatness of the strip and better cooling- and coiling practices, and to decrease rejects;
- minimize temperature differences across the strip during rolling in the finishing mill;
- optimisation of the grain size distribution and texture across the strip width (reduction of coarse grain in strip edge regions).
- ensure best product quality and better compliance with end customers’ requirements.