| 摘要 |
The machinability of carbon steels is improved by carrying out a preliminary deoxidation with one or more metals having a high affinity for oxygen, such as aluminium, magnesium, zirconium or calcium, or alloys thereof, and then, after the deoxidation products have risen out of the bath, deoxidising finally with an alloy rich in silicon and substantially free from aluminium, whereby there are formed in the bath glassy occlusions rich in silica. In a modification of the process the preliminary treatment may be partially or wholly replaced by a vacuum degassing treatment, while it is also possible to add to the melt nucleating elements such as tantalum, niobium, titanium or vanadium. |
