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KAISER ALUMINUM TECHNICAL REFERENCE
LIBRARY No. 1014
Glossary of Terms
| AGING A
reaction of the alloying elements taking place in the heat-treatable alloys after solution
heat-treatment that brings about an increase in hardness and strength with a decrease in
ductility. The reaction may occur at room temperature and is defined as natural
aging. The speed of the reaction can be accelerated if it takes place at an
elevated temperature in the 250°F to 450°F range where it is defined as artificial
aging. |
| ANNEALING A thermal treatment used to soften the metal by
removal of stresses from cold working or by coalescing precipitates from solid solution.
When the metal is fully softened it is call a full anneal. When
only some of the stresses are removed it is called a partial anneal.
In the latter case, the metal is stronger but less ductile than in the case of a full
anneal. |
| BAR A solid section of metal that is long in relation to
its cross section, which is square, rectangular or hexagon and in
which at least one perpendicular distance between parallel faces is 0.375 inches or
greater. |
| COLD FINISHED Rod or bar brought to a final diameter or thickness
by means of a cross section reduction applied to the metal when it is at room temperature.
Examples are cold rolling, cold drawing or cold extruding. |
| COLD WORKING Material reduction
or deformation carried out at
temperatures below those resulting in the recrystallization or annealing of the metal. Cold
working of the metal will bring about strain-hardening with an increase in
strength and hardness. |
| ELONGATION This property designates the ability of the metal
to stretch, or elongate, when it is subjected to an applied stress. The distance the metal
will stretch from the point where yielding begins to the point where the metal fractures
is expressed as a percentage and is known as the elongation. |
| HEAT-TREATABLE
ALLOYS Alloys, typically in
the 2XXX, 6XXX and 7XXX series, that achieve their maximum strength through
solution heat treating. |
| SOLUTION HEAT TREATING Normally used to describe a process where metal is
heated at a high enough temperature to put soluble elements into solid solution. |
| HOT WORKING Working the metal at such a high temperature that
strain hardening does not occur. |
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| NON-HEAT-TREATABLE ALLOYS The
most definitive term for the 1XXX, the 3XXX, the 5XXX and some 4XXX alloy classes. These
alloys gain strength through cold working and lose strength through thermal treatments. |
| QUENCHING A closely controlled rapid cooling of metal from
some type of high temperature operation such as heat treating or extruding. The cooling
medium is usually water and the purpose is to chill the metal quickly and lock the
alloying elements into the dispersed positions imparted to them by the high temperature
operation. |
| ROD A solid round section 0.375" or greater in
diameter. |
| STRESS RELIEVING Often confused with ferrous stress relieval
treatments, this process mechanically stress relieves the aluminum by stretching the rod
or bar thus achieving a permanent increase in length and low residual stress levels. |
| ULTIMATE TENSILE
STRENGTH (UTS) A common term
to describe mechanical strength. This metal property denotes how much stress can be
gradually applied to the metal before it fractures. Tensile testing is done by pulling two
ends of a test sample in opposite directions under a constantly increasing force,
subjecting the product to stress. The stress is measured until the product is pulled in
two. |
| WIRE A definition of wire is just about the same as the
definition for bar, in that wire can be almost any cross section, but, unlike bar,
wire can be round. The major difference lies in the fact that the minor
dimension for bar must be at least three-eighths of an inch (.375")
while the major dimension for wire must be under three-eighths
of an inch. |
| WROUGHT PRODUCTS Products which can began as raw material castings
and are mechanically worked by processes such as rolling, extruding and forging to the
extent that all remnants of the cast metallurgical structure have been removed. |
| YIELD
TENSILE STRENGTH (YTS) A
property of the material that describes the stress at which the material exhibits a
specific permanent set. That is the point at which it will not spring back to its original
length when stress in the material is relieved. For aluminum the yield strength is usually
measured at the point where the stress applied to the material causes a 0.2% permanent
set. |
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