Improvement in cutting characteristics in free-cutting soft steels by control of their inclusion contentFunded under: ECSC-STEELRES 8C
The aim of this project was to produce free-cutting, soft, S300 series steels by "killing with silicon" in combination with a ladle treatment designed to modify the inclusion state. Two Ca-treated S300Si melts were prepared and the effect of the melt preparation type on the physical-metallurgical properties of inclusions were investigated with an eye to its machinability under a wide range of cutting conditions. The main objective was to understand the phenomena and the mechanisms that result in marked improvements in machinability through formation of a selective transfer layer or protective coating under the prevailing cutting conditions. Only a few grades of carbides permit formation of deposits on the cutting tools. To explain the mechanisms forming the selective layer, the accepted hypothesis is that at the interface between the layer and the WC on the tool, there is a formation of compounds of types (Co, WO(3)) and (Fe(x), Co(y) and W(z))C resulting from carbide decomposition. These are removed by the cutting tool (through wear) and prevent MnS adhesion. At the interface between the layer and (W, Ti, Ta, Nb)C, an adherent compound of the type TiO(x)S(y)C(z) would be formed, ensuring contact between layer and tool.
Bibliographic Reference: EUR 16020 FR (1995) 83 pp., FS, ECU 11.50
ISBN: ISBN 92-827-4084-6
Record Number: 199411664 / Last updated on: 1995-03-21
Original language: fr
Available languages: fr