IMPROVE- MENTS IN THE MANUFACTURE OF STEEL
Year: 1879

page_text: LETTERS PATENT to Sidney Gilchrist Thomas, of 3, Queen's Road Villas,
Queen's Road, Wandsworth Road, London, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF STEEL"
PROVISIONAL SPECIFICATION left by the said Sidney Gilchrist Thomas
.at the Office of the Commissioners of Patents on the 3rd September 1879.
SIDNEY GILCHRIST THOMAS, of 3, Queen's Road Villas, Queen's Road, Wandsworth
Road, London. "IMPROVEMENTS IN THE MANUFACTURE OF STEEL."
1
My Invention consists in a means of economising manganese and improving the
quality of steel in the manufacture of steel from phosphoretic pig-iron, as described
in my Patents, Nos. 289, in the year 1878, and 1313, in the year 1879. I have
found that when spiegel is added to the dephosphorised metal in the ordinary way
there is a rather excessive waste of manganese, and sometimes a tendency to red
shortness in the steel. This I find entirely avoided by adding to the dephos-
phorised metal in the converter or ladle a little molten hæmatite pig before adding
the spiegel or ferro-manganese. I sometimes add ferro-manganese in lumps first,
immediately afterwards introducing the molten pig-iron before the ferro-manganese
has had time to melt. Instead of a mixture of hoematite and ferro-manganese
or spiegel, I sometimes add ferro-manganese rich in silicon, which has a similar
beneficial effect.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sidney. Gilchrist Thomas in the Great Seal Patent Office on the
2nd March 1880.
SIDNEY GILCHRIST THOMAS, of 3, Queen's Road Villas, Queen's Road, Wandsworth
Road, London. "IMPROVEMENTS IN THE MANUFACTURE OF STEEL."
My Invention consists in a means of economising manganese and improving the
quality of steel in the manufacture of steel from phosphoretic pig iron, as described
in my Patents, No. 289, in the year 1878, and 1313, in the year 1879. I have
found that when spiegel is added to the dephosphorized metal in the ordinary way
there is a rather excessive waste of manganese, and sometimes a tendency to red
shortness in the steel. This I find is entirely avoided by adding to the dephosphorized
metal in the converter or ladle a little molten hoematite or other pure pig iron, by
which I mean a pig containing under 15 per cent. of phosphorus and sulphur, before
adding the spiegel or ferro-manganese. I sometimes add ferro-manganese in lumps
first, immediately afterwards introducing the molten pig-iron before the ferro-
manganese has had time to melt, but I prefer to add the molten pig-iron first, and
then molten spiegel or ferro-manganese. About (4 or 5) four or five per cent. of pig-
iron, and about an equal quantity of rich spiegel or ferro-manganese I have found to
be a good proportion. I do not claim the addition to dephosphorized metal of silico-
ferro manganese or silicide of iron, or silicide of manganese, all of which are
expensive substances, the use of which does not successfully attain my object; nor
do I claim the use of spiegel or ferro manganese for recarbonizing steel; but I
claim the herein described process for preventing oxidation of manganese, and
improving the quality of the dephosphorized Bessemer steel by adding to the
decarbonized and dephosphorized metal pure pig-iron and spiegel or ferro manganese,
substantially as in the manner described.
In witness.whereof, I, the said Sidney Gilchrist Thomas, have hereunto set my
hand and seal, this First day of March 1880.