After the success of the basic Bessemer process was assured the same principle was tried in the open-hearth; a basic bottom of dolomite or of magnesite was substituted for the acid sand bottom, and care was taken to secure a basic slag in the bath.
Success was greater than in the Bessemer; phosphorus was eliminated and a better article in every way was made by this process, now used extensively over the whole civilized world.
This is the basic open-hearth process.
Neither the basic Bessemer process nor the basic open-hearth removed sulphur, so that this element must still be kept low in the original charge, until some way shall be found for its sure and economical elimination.
The four general divisions, then, are:
| Converted or Cemented Steel. | ||||
| Crucible-cast Steel. | ||||
| Bessemer |  | Acid |  | Cast Steel. |
| Basic | ||||
| Open-hearth | | Acid | | Cast Steel. |
| Basic | ||||
Little or nothing more will be said of the first kind, as it has been so thoroughly superseded by the cast steels. After a statement of the most patent applications and uses of the different cast steels the discussions which follow will apply to all, because practically they are all governed by the same general laws.
II.
APPLICATIONS AND USES OF THE
DIFFERENT KINDS OF STEEL.
Where exact uniformity of composition is not a necessity, and where welding is required, cemented or converted steel may be preferred to cast steel, because the converted bar retains the occluded layers of slag which give to wrought iron its peculiar welding properties, and for this reason blister- or shear-steel may be welded more easily and surely than cast steel. For tires, composite dies, and many compound articles this steel will do very well, and it may be worked with good results by almost any smith of ordinary skill; however, owing to the more uniform structure and the greater durability of the cast steels, they have, even for these purposes, almost entirely displaced the more easily worked, but less durable, cemented steels.