MANUFACTURE OF STEEL
Year: 1879

page_text: LETTERS PATENT to Edward Pritchard Martin, of Blaenavon, in the County of
"IMPROVEMENTS IN
Monmouth, Manager of Iron Works, for the Invention of
THE MANUFACTURE OF STEEL."
PROVISIONAL SPECIFICATION left by the said Edward Pritchard Martin
at the Office of the Commissioners of Patents on the 23rd June 1879.
EDWARD PRITCHARD MARTIN, of Blaenavon, in the County of Monmouth, Manager
of Iron Works. "IMPROVEMENTS IN THE MANUFACTURE OF STEEL."
My Invention relates an improved process for manufacturing a high quality
of steel or ingot-iron by a combination of the Bessemer and openhearth processes
from pig containing much phosphorus or phosphorus and sulphur. For this purpose
I blow the molten pig in either a vertical or tipping Bessemer convertor with an
ordinary silicious lining till nearly all the silicon is removed. I then run the metal
(without the slag) into a Siemens, Pernot, or other openhearth furnace (preferably
a Pernot furnace). This openhearth furnace must be lined with basic material,
preferably the magnesian lime bricks, described in the Specification of a Patent
granted to S. G. Thomas, No. 908, in the year 1878, and has spread on its hearth a
large quantity of lime with a certain amount of oxide of iron so as to produce a
highly basic calcareous slag containing over forty per cent. of lime and magnesia, by
means of which the phosphorus and a considerable amount of the sulphur are
rapidly removed. When the charge has been brought to the desired pitch, the slag
is tapped off before the spiegel or ferro-manganese is introduced, a very high quality
of steel may be thus produced from the cheapest materials. A part of the charge
in the openhearth furnace may consist of scrap iron.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Pritchard Martin in the Great Seal Patent Office on the
22nd December 1879.
EDWARD PRITCHARD MARTIN, of Blaenavon, in the County of Monmouth,
Manager of Iron Works. IMPROVEMENTS IN THE MANUFACTURE OF STEEL."
"6
My Invention relates to an improved process for manufacturing a high quality of
steel or ingot iron by a combination of the Bessemer and open-hearth processes
from pig containing much phosphorus or phosphorus and sulphur. For this purpose
I blow the molten pig in either a vertical or tipping Bessemer or other converter,
with an ordinary silicious lining till nearly all the silicon is removed. I prefer to
stop the blow two or three minutes before the drop of the flame.
I then run the metal (without the slag) either directly through a runner or by
the intervention of a ladle into a Siemens, Pernot, or other open hearth furnace
(preferably a Pernot or other rotating gas furnace). This open-hearth furnace must
be lined with basic material, preferably the magnesian-lime bricks described in the
Specification of a Patent granted to S. G. Thomas, No. 908, in the year 1878, and
has spread on its hearth a large quantity of limestone or of lime, which I always
prefer to mix with a large quantity (preferably an equal weight) of oxide of iron,
so as to produce a highly basic calcareous slag, which may advantageously contain
over forty per cent. of lime and magnesia. By the action of these bases the phos-
phorus and a considerable amount of the sulphur are rapidly removed. The greater
the agitation the more rapid will be the dephosphorisation. When the charge has
been brought to the desired pitch, as indicated by the fracture of a sample showing
the phosphorus to be removed, the slag is tapped off before the spiegel or ferro-
manganese is introduced.
A part of the charge in the open hearth furnace may
consist of scrap iron. A very high quality of steel may be thus produced from the
cheapest materials.
I claim not the mere dephosphorising by basic additions, but the improved com-
bined process herein described for the manufacture of steel from phosphoric pig iron.
In witness whereof, I, the said Edward Pritchard Martin, have hereunto set
my hand and seal, this Twentieth day of December, 1879.
HAND
:
AZLY