Joseph Herbert on tue 1 sep 98
Pretty interesting but dangerous stuff here.
Adding to the message from D. Kim Lindaberry about the Graphite crucible
project in Ghana - information requested - The pouring of iron or steel, as
seen in the famous pictures of the Bessemer Converter discharging its load, is
kind of an inaccurate idea. It can be done but it is mostly not done that
way. In the classic blast furnace, the iron ore, limestone, and coke are
charged into the top of the furnace and the liquid iron runs out the bottom to
forms or thermos rail cars. The blast furnace is sort of there. In the open
hearth method of making steel, the iron is charged into the furnace from the
thermos rail cars and then subjected to oxygen blasts, alloy additions, and
slag former additions. After the process is completed and the "heat" is now
liquid steel, a hole is made in the bottom of the furnace and the liquid steel
flows down a chute into a large ladle. As the steel fills the ladle the slag
floats on the top of the liquid. When the steel approaches the top of the
ladle, the slag flows out the pour spout into a slag holding vessel. The
filled ladle is taken by the crane to the form filling area where the ingot
forms are filled with liquid steel. A cutting torch or oxygen lance cuts a
small hole in the bottom of the ladle. From this opening, the steel flows
into the forms. The ladle is never tipped to dispense the steel.
My suggestion, as a person with little knowledge, is as follows: The
mechanical stresses of tipping and pouring are incompatible with the
requirements for holding while heating in so far as the choice of material
characteristics is concerned. As Mr. Lindaberry suggests, the furnace should
be stationary. At the very most you might lift a container and set above a
channel that leads to molds. Opening a previously prepared hole in the lower
part of the container would allow the iron to flow in the channel to the
molds. Also as Mr. Lindaberry suggests, these problems have been solved many
times before. While the history of iron making may not be posted on the net,
it is surely available in a technical library.
One thing further, the current method of making steel, the basic oxygen
furnace operates by placing the heating apparatus over the container of the
starting material. When the process is over the entire top, heaters and all,
is removed to allow recharging. Here is Mr. Lindaberry s cupola idea. Build
an insulated, mechanically strong, container for your starting material.
Construct a removable top that contains the heaters to melt the iron. When
the iron is liquid, "Tap the heat" by removing a plug in the bottom of your
container. The open hearth workers did this with iron bars or small charges
of dynamite. Let gravity be your friend and have the hot metal flow into your
molds. Move the molds, not the furnace.
Great good luck in a daunting and scary undertaking.
Joseph Herbert
JJHerb@aol.com
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