| Manufacturing Home
Metal Casting Principles
Metal Casting Operation
Effect Of Gases On Metal Casting
Metal Casting Design
Expendable Mold Casting
Plaster Mold Casting
Ceramic Mold Casting
Shell Mold Casting
Vacuum Casting or V-process
Expanded Polystyrene Casting
Permanent Mold Casting
Basic Permanent Mold Casting
Vacuum Permanent Mold Casting
Hot Die Casting
Cold Die Casting
True Centrifugal Casting
| NEED MACHINES AND EQUIPMENT?
| HIGH QUALITY--LOW COST
SYSTEMS FOR FORGING
CNC EDM WIRE CUTTING
CNC EDM DIE SINKING
INDUCTION TUBE AND
WE CAN PROVIDE MACHINES IN SIZES FROM SMALL TO VERY LARGE:
IF YOU WANT TO OPTIMIZE YOUR MANUFACTURING PROCESS
WITH THE RIGHT MACHINERY,
THEN TALK TO THE EXPERTS.
Continuous casting, also referred to as strand casting, is
a process used in manufacturing industry to cast a continuous length of metal. Molten
metal is cast through a mold, the casting takes the two dimensional profile of the mold
but its length is indeterminate. The casting will keep traveling downward, its length
increasing with time. New molten metal is constantly supplied to the mold, at exactly
the correct rate, to keep up with the solidifying casting. Industrial manufacture of
continuous castings is a very precisely calculated operation. Continuous casting can
produce long strands from aluminum and copper, also the process has been developed
for the production of steel.
Molten metal, from some nearby source, is poured into a tundish.
A tundish is a container that is located above the mold, it holds the liquid metal
for the casting. This particular casting operation uses the force of gravity to fill the
mold and to help move along the continuous metal casting. The tundish is where the
operation begins and is thus located high above ground level, as much as
eighty or ninety feet. As can be seen, the continuous casting operation may require
a lot of space.
It is the job of the tundish to keep the mold filled to the right level throughout
the manufacturing operation. Since the metal casting is constantly moving through the
mold, the tundish must always be supplying the mold with more molten metal to
The supplying of metal to the mold is not only going on throughout the entire
manufacturing operation, it must be carried out with accuracy. A control system
is employed to assist with this task. Basically the system can sense what the level of
molten metal is, knows what the level should be, and can control the pouring of the
metal from the tundish to ensure the smooth flow of the casting process.
Although the tundish can typically hold several thousand pounds of metal, it
too must be constantly supplied from the source of molten material.
The tundish also serves as the place where slag and impurities are removed from
the melt. The high melting point and reactive nature, at high temperatures, has always made
steel a difficult material to cast. When a manufacturing operation is continuously casting
steel, the reactivity of the molten steel to the environment needs to be controlled. For this
purpose, the mold entrance may be filled with an inert gas such as argon. The inert gas
will push away any other gases, such as oxygen, that may react with the metal. There is
no need to worry about the inert gas reacting with a molten metal melt, since inert gases
do not react with anything at all.
The metal casting moves quickly through the mold, in the continuous manufacture of the
metal part. The casting does not have time to solidify completely in the mold. As can be
remembered from our discussion on solidification, a metal casting will first solidify from the
mold wall, or outside of the casting, then solidification will progress inward. The mold in
the continuous casting process is water cooled, this helps speed up the solidification of the
metal casting. As stated earlier, the continuous casting does not completely harden in the
mold. It does, however, spend enough time in the water cooled mold to develop a protective
solidified skin of an adequate thickness on the outside.
The long metal strand is moved along at a constant rate, by way of rollers. The rollers
help guide the strand and assist in the smooth flow of the metal casting out of the mold and along
its given path. A group of special rollers may be used to bend the strand to a 90 degree angle.
Then another set will be used to straighten it, once it is at that angle. Commonly used in
manufacturing industry, this process will change the direction of flow of the metal strand from
vertical to horizontal.