Improving the machinability of stainless steels
Regarding the steel, we put in evidence the beneficial role of sulphides, especially at low machining speed, copper and calcium at high speed. Several investigations demonstrated that using a constant analysis, both sulphide and copper tend to increase tool life and decrease the cutting efforts. Regarding the turning process (and all operations without confinement of chip) we demonstrated the possibility of dry machining, giving proper cutting conditions. Regarding tools and cutting fluids, the project puts forward a new formulation of cutting oil for MQL. Combined with an optimised geometry (opened flute, polished surface, molybdenum sulphide and TiN multiplayer coating) the specifically difficult drilling process can be handled economically. These results have been extended to the tapping process. The MQL process is now available with its cleaning and oil recycling gains. The oil has been optimised to provide a better lubrication with an increased cooling effect due to a low viscosity, a high aerosol formation and a strong evaporation. An industrial heat was cast in Ugine that regroups the improvements mentioned above. Due to the economic environment, a fully optimised grade (with an analysis out of norm) could not be proposed. This industrial heat reached unprecedented machinability during turning, while confirming its very interesting properties during the other operations. The corrosion tests confirm the detrimental effect of sulphur on corrosion resistance. Copper, on the other hand, brings a small advantage in generalised corrosion resistance. Finally, the cost and environmental assessments show the interest of promoting both optimised stainless grades and tools together with optimised MQL.
Bibliographic Reference: EUR 21801 EN (2005), 142 pp. Euro: 25
Availability: http://bookshop.europa.eu/is-bin/INTERSHOP.enfinity/WFS/EU-Bookshop-Site/en_GB/-/EUR/ViewPublication-Start?PublicationKey=KINA21801 (Catalogue Number: KI-NA-21801-EN-S)
ISBN: ISBN 92-79-00057-8
Record Number: 200618439 / Last updated on: 2005-12-15
Original language: en
Available languages: en