Community Research and Development Information Service - CORDIS


Final report on Contract No 7210-PR/092, 1 July 1998 to 31 December 2001.

The aim of this cooperative work programme was to improve the understanding of the effects of compositional and processing variables on the production of hot-rolled high-strength ferritic-bainitic and TRIP steels with attractive combinations of strength and ductility. The base composition chosen was 0.15 % C, 1.5 % Si, and 1.5 % Mn. Based on variations in alloy content around the base composition, a series of experimental compositions was produced. Additions of Cr, Mo, p and Nb were included.

Thermomechanical simulations were performed and the microstructures were analysed using metallographical and X-ray measurements. Laboratory rolling trials were carried out to verify the results from the simulations. A P-containing variant showed good properties meeting the target of A5 x Rm > 20 000 MPa%.

The P-containing variant was selected for the industrial trials. The tensile elongation values of the mill trial materials were promising and the forming limit diagram calculated using the n value indicates that the trial material has almost twice as good formability as HSLA steel. The hole-expansion results were typical for steel grades of this strength level. The impact toughness was poor. Spot weldability and laser weldability were satisfactory, but MIG/MAG welding was detrimental and cannot be recommended.

For mills with relatively short run-out table configurations, a P-containing steel is suitable as it increases the rate of ferrite formation compared with other alloy additions.

Additional information

Authors: KUJANPÂÂ A, Rautaruukki, Raahe (FI);ANELLI E, CSM, Rome (IT);DI NUNZIO P E, CSM, Rome (IT);WADE B, Corus UK Ltd, Rotherham (GB)
Bibliographic Reference: EUR 20567 EN (2002), pp.208. Euro: 31.00
Availability: EUR-OP reference: KI-NA-20567-EN-C Available from EUR-OP sales agents URL:
ISBN: ISBN: 92-894-4532-7
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