| TERMINOLOGY |
Additional Helpful Data |
| AGING - In a
metal or alloy, a change in properties that generally occurs slowly
at room temperature and more rapidly at higher temperatures. |
|
| ALLOYING
ELEMENTS - An element added to a metal to effect changes in property,
and which remains within the metal. |
| ANNEALING - Heating to and
holding at a suitable temperature and then cooling at a suitable rate,
for such purposes as reducing hardness, improving, machinability,
facilitating cold working, producing a desired microstructure, or
obtaining desired mechanical, physical or other properties. Annealing
is a broad term covering such thermal treatments as full annealing,
normalizing, etc. When applying to ferrous alloys, the term “annealing,”
without qualification, implies full annealing. |
| BLISTER
- A defect produced by gas bubbles. |
| BLUE ANNEALING - Heating hot rolled ferrous sheets
in an open furnace to a temperature within the transformation range
and then cooling in air, in order to soften the metal. The formation
of a bluish oxide on the surface is incidental. |
| CARBON STEEL - Steel is classed as
carbon steel when no minimum content is specified or required for
aluminum, boron, chromium, cobalt, columbium, molybedenum, nickel,
titanium, tungsten, vanadium or zirconium, or any other element added
to obtain a desired alloy effect; when the specified minimum for copper
does not exceed .040%; or when the maximum content specified for manganese
does not exceed 1.65%; silicon .60%; copper .60%. |
| CASE - In a ferrous alloy, the outer portion that has
been made harder than the inner portion, or core, by carburizing and
hardening. |
| DECARBURIZATION - The loss of carbon
from the surface of a ferrous alloy as a result of heating in a medium
that reacts with the carbon at the surface. |
| HARDENING - Increasing the hardness by suitable treatment,
usually involving heating and cooling. When applicable, the following
more specific terms should be used: age hardening, case hardening,
flame hardening, induction hardening, precipitation hardening and
quench hardening. |
| HEAT TREATMENT - Method of heating
and cooling of finished metals or alloys to produce certain desirable
properties and conditions. |
| PIG IRON - High carbon iron - made by reduction of
iron ore in the blast furnace. |
| YIELD POINT - The load per unit of
original cross-section area at which a marked increase in the deformation
of the specimen occurs without increase of load. It is usually calculated
from the load determined by the drop of the beam of the testing machine
or by use of dividers. |
| TEMPERING - Reheating a quench-hardened or normalized
ferrous alloy to a temperature below the transformation range and
then cooling at any desired rate. |
| TENSILE STRENGTH - The maximum load
per unit of original cross-sectional area obtained before rupture. |
| SEAM - On the surface of metal, an unwelded fold or
lap, which appears as a crack, usually resulting from a defect obtained
in casting or working. |
| SLAB - A piece of metal, intermediate
between ingot and plate, with the width at least twice the thickness
for rolling down into plates. |
| QUENCHING - Cooling rapidly from the hardening temperature
by subjecting the part to the proper coolant such as oil, water, molten
salt, molten lead, airblast, etc. |
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