Furnace Types and Terms
Furnace Types
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use hydrogen to protect materials from oxidation, relieving the residual
stresses produced during the processing of steel strips, tubes and rods.
The hydrogen also has high heat transfer properties that aid in the
reduction of production cycles.
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heat treat one load at a time. Batch furnaces are used in applications
in which large parts and complex alloy grades must be treated.
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are continuous-type furnaces that move parts using a mesh-type or cast-link
belt.
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are large towers or cylinders that have a heat resistant lining and
force gusts of hot air and gases up through the furnace load.
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are batch-type furnaces that are used for lower stress-relieving ranges.
Car furnaces utilize a car on rails for entering and exiting the furnace
area.
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are heat-treating furnaces through which materials continuously enter
one door and are discharged through another.
- are continuous-type furnaces in which the parts are
conveyed through a tunnel-like heating area on hooks or fixtures, in
order to minimize distortion.
- are machines that use electricity to heat.
- , used to melt glass, have burner ports and the checkers
on the same end. While end port regenerative furnaces are initially
energy efficient, the checker volume eventually decreases through plugging,
resulting in the gradual decrease of melting efficiency over the life
of the furnace.
-
burn gas to create heat.
-
heat the material and cool it to bring it to a desired point for increased
strength, ageing or manipulation.
-
use combined electrical resistance and hysteresis losses to heat metal
by exposing it to the varying magnetic field around a coil-carrying
alternating current.
-
are continuous-type furnaces in which parts are charged into the furnace
in containers on a periodic basis. These containers are pushed against
a line of containers that have already been heated, advancing the containers
towards the discharge end of the furnace, where they are put into use.
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are a type of continuous furnace that utilize an internal screw to advance
the parts, giving good control of the retention time within the heated
chamber.
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are a type of continuous furnace that advances the parts along the hearth
using a reciprocating shaker motion.
- , used to melt glass, have burner ports on opposite ends
and incorporate a greater checker volume than the end port regenerative
furnace, resulting in higher pull rates.
-
heat materials below their melting point to make them more dense or
compact and solid, which can lead to shrinkage.
-
are furnaces in which stock is charged and removed in batches through
a slot or opening.
-
are airtight and use low atmospheric pressure as the atmosphere for
heating.
Furnace Terms
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The processes of heating, holding temperature and cooling in order to
accomplish a specific objective with the material being heated.
- A structure
that can be developed from the hot rolling of steel, resulting in a layering
effect.
- Annealing
done in an extremely hot atmosphere that prevents the occurrence of discoloration
and may reduce oxides.
- Heating the surface
of steel in contact with carbon-rich solids, liquids or gases in order
to add carbon to the material.
- Making the
surface layer of a steel material substantially harder through heat treating.
- The separate
sensor or instrument of a piece of thermal processing equipment which
controls its own temperature individually.
- A process
that is used to deter cracking or hardening or to achieve a desired microstructural
result. The controlled cooling process involves cooling the material from
an elevated temperature in a selected method.
- Stresses
resulting from irregular temperature distribution during cooling.
- Enclosures that are used for a wide variety of process heating
applications.
- Heating material
or products prior to a subsequent thermal or mechanical treatment.
- Quickly cooling
from a high temperature.
- Placing parts on a
rack or tray prior to heat treatment in order to prevent heat-related
distortions and to keep the parts separated.
- A term describing
materials that have a very high melting point, making them ideal for linings
of furnaces and kilns.
- Surface flaking or
chipping resulting from improper heat treatment or material dissociation.
- A quick cooling
process in which spray nozzles are used to spray water or other liquids
on a part.
- The
process of heating a part to slightly above its normal operating temperature
and then cooling it to room temperature. Stabilizing treatments are done
prior to finishing the part to final dimensions and for the purpose of
ensuring dimensional stability.
- A heat treatment
done at low temperatures in order to balance stresses in a cold-worked
part without decreasing the mechanical strength imparted to the product
through the cold-working process.
- Heating and
holding the desired temperature long enough to reduce residual stresses,
then slowly cooling.
- Heating at a
temperature above the point where equilibrium phase transformation should
occur but without actually making a transformation.
- A device that
measures temperature through thermal electromotive force.
-
The temperature equilibrium at which a change in the phase occurs.
- A quick cooling
process using water as the quenching medium. Water quenching is inefficient
at the beginning, or hot, stage of the quenching process.