Optimisation of the influence of boron on the properties of steel
The effect of boron and the need to control its location and chemical state have been known since the 1940s. Early attempts to commercially produce heat treatable steels resulted in variable properties due to difficulties in ensuring that boron was present in the desired form, i.e. as soluble boron in the case of steels where boron was present to enhance hardenability. On the other hand, similar problems can be encountered in areas where an unprotected boron addition is made to modify other properties, e.g. ductility or formability in low carbon steels. This ECSC project was carried out to better characterize and understand the precise role of boron in a range of steels. The main studies carried out and results obtained in the frame of this project are: the characterisation of the effect of boron additions on austenite grain size show that, as heat treatment temperature increases, grain coarsening occurs, first in the boron unprotected plain carbon steels, then the plain carbon steels and finally in the boron protected by niobium, aluminium or titanium because the nitrides formed by these elements stop the increase; the neural network Jominy prediction software and training tool developed provides accurate predictions as regarding the general trend of the curves and covers a wide range of heat treatable steels and finally; boron is shown to be effective in increasing formability and decreasing ageing response in wire drawing quality steels by tying-up free nitrogen and promoting coarse ferritic grain size. Keywords: boron, heat treatable steels, hardenability, Jominy, prediction, formability, ageing, wire drawing.
Bibliographic Reference: EUR 22446 EN (2007), 137 pp. Euro: 35
Availability: Katalogue Number: KI-NA-22446-EN-S The paper version can be ordered online and the PDF version downloaded at: http://bookshop.europa.eu
ISBN: ISBN: 978-92-79-04875-3
Record Number: 200719237 / Last updated on: 2007-07-05
Original language: en
Available languages: en