DEVELOPMENT OF TREATMENTS FOR PRODUCTION OF LOW AND ULTRA-LOW PHOSPHORUS STEEL
The objective of the research reported here has been to establish suitable dephosphorisation (de-P) treatments : - under oxidising conditions, to attain a phosphorus content in the region of 20 ppm while ensuring a dephosphorising degree of around 70%; - under reducing conditions, to achieve a dephosphorizing degree of around 30% for stainless steels. In the case of dephosphorising under oxidising conditions it was found that all the treatments ensure Delta P/P values of 60 to 80% and P values of even less than 10 ppm. However, dephosphorising at the tapping stage is best from the economic standpoint. The problem of P pick-up was resolved by paying careful attention to the heats themselves (ensuring complete deslagging, and using low-P ferroalloys and refractories). In the case of dephosphorising under reducing conditions, by optimising process control (especially as regards the final temperature, ca. 1500 C, the quantity of covering slag, 25-30 Kg/t, the quantity of Ca added, 10 Kg/t, and the composition of the atmosphere, O(2) less than 1%) a dephosphorising degree of around 20% was achieved.
Bibliographic Reference: EUR 12665 IT (1990), 94 PP., FS, ECU 10 ISBN 92-826-1337-2 THE OFFICE FOR OFFICIAL PUBLICATIONS OF THE EUROPEAN COMMUNITIES, L-2985 LUXEMBOURG
ISBN: ISBN 92-826-1337-2
Record Number: 1989128055200 / Last updated on: 1992-08-10
Original language: IT