Precipitation due to hot rolling in the finishing mill
By means of a thermo-mechanical treatment simulator working in uniaxial compression using a technique of selective electrolytic extraction of the precipitates, it has been possible to formulate a quantitative description of the kinetics of the microalloy precipitated elements Nb and Ti during hot rolling. In HSLA, two forms of precipitate can be distinguished: - the incoherent precipitates, large particles which are poor hardeners, formed either in the mill, at high temperature on the run-out table or in the coiler, if the temperature is sufficiently high; - the coherent precipitates, fine particles which are very good hardeners, formed either after transformation on the run-out table or in the coiler at temperatures in the range 500 -650 . In addition to rolling parameters and steel chemistry, conditions of cooling and coiling essentially determine the mechanical properties of these steels by controlling the balance between the coherent and incoherent fractions at precipitation. In particular, increasing the cooling rate increases the coherent fraction at the expense of the incoherent fraction. The influence of the coiling temperature is less pronounced when precipitation begins on the run-out table.
Bibliographic Reference: EUR 12724 FR (1990) 62 pp., FS, ECU 7.50
ISBN: ISBN 92-826-1383-6
Record Number: 199010961 / Last updated on: 1994-12-01
Original language: fr
Available languages: fr