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Pancake Grain Structure |
A structure in which the lengths and
widths of individual grains are large compared to their thicknesses. |
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Parent Coil |
A coil which has been processed to
final temper as a single unit. The parent coil may subsequently be
cut into two or more smaller coils or into individual sheets or
plates to provide the required width and length. |
|
Parent Plate |
A plate that has been processed to
final temper as a single unit. The parent plate may subsequently be
cut into two or more smaller plates to provide the required width
and length. |
|
Partial Annealing |
Thermal treatment given cold worked
metal to reduce the strength to a controlled level. |
|
Pass |
- A term indicating the process of
passing metal through a rolling mill.
- A single transfer of metal through
a stand of rolls.
- The open space between two grooved
rolls through which metal is processed.
- The weld metal deposited in one
run along the axis of a weld.
|
|
Passivation |
The changing of the chemically active
surface of a metal to a much less reactive state. Contrast with
activation. |
|
Patterned or Embossed Sheet |
A sheet product on which a raised or
indented pattern has been impressed on either on or both surfaces by
the use of rolls. |
|
Permanent Set |
Non-elastic or plastic, deformation
of metal under stress, after passing the elastic limit. |
|
Phase |
A physically homogeneous and distincy
portion of a material system. |
|
Phase Diagram |
Synonymous with constitutional
diagram. |
|
Photomicrograph |
A photographic reproduction of any
object magnified more than ten diameters. The term micrograph may be
used. |
|
Physical Properties |
- Properties other than mechanical
properties, that pertain to the physical nature of a material;
e.g., density, electrical conductivity, thermal expansion,
reflectivity, magnetic susceptibility, etc.
- The properties, other than
mechanical properties, that pertain to the physics of a
material; for example, density, electrical conductivity, heat
conductivity, thermal expansion.
- Those properties familiarly
discussed in physics, exclusive of those described under
mechanical properties; for example, density, electrical
conductivity, co-efficient of thermal expansion. This term often
has been used to describe mechanical properties, but this usage
is not recommended.
|
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Pickup |
Small particles of oxide adhering to
the surface of a product. |
|
Pickup, Repeating |
Repeating depression caused by a
particle adhering to a rotating roll over which the metal has
passed. Also referred to as "Dent, Repeating". |
|
Pickup, Roll |
Small particles of aluminum and
aluminum oxide generated in the roll bite which subsequently
transfer to the rolled product. It may be distributed uniformly
and/or in streaks. See also "Streak, Coating." |
|
Pipe |
- The central cavity formed by
contraction in metal, especially ingots, during solidification.
- The defect in wrought or cast
products resulting from such a cavity.
- An extrusion defect due to the
oxidized surface of the billet flowing toward the center of the
rod at the back end.
- A tubular metal product, cast or
wrought.
|
|
Pit (defect) |
A sharp depression in the surface of
the metal. |
|
Pitting |
Forming small sharp cavities in a
metal surface by nonuniform electro-deposition or by corrosion. |
|
Pitting Corrosion |
Localized corrosion resulting in
small pits or craters in a metal surface. |
|
Plastic Deformation |
- Deformation that remains, or will
remain, permanent after release of the stress that caused it.
- Permanent distortion of a material
under the action of applied stresses.
|
|
Plasticity |
- The ability of a metal to be
deformed extensively without rupture.
- The capacity of a metal to deform
non-elastically without rupturing.
|
|
Plate |
A flat-rolled product whose cross
section is rectangular and whose thickness in one-quarter of an inch
(.250") or more.
Alclad Plate:
Composite plate comprised of an aluminum alloy core having both
surfaces (if on one surface only, Alclad One Side Plate) a
metallurgically bonded aluminum or aluminum alloy coating that is
anodic to the core, thus electrolytically protecting the core
against corrosion.
Odd-Shaped Plate Blanks:
Plate cut into shapes other than circles or rectangles.
Plate Circles:
Circles cut from plate.
Tread Plate:
Sheet or plate having a raised figured pattern on one surface to
provide improved traction. |
|
Plating |
A thin coating of metal laid on
another metal. |
|
Polished Surface |
The finish obtained by buffing with
rouge or similar fine abrasive, resulting in a high gloss or polish. |
|
Polishing |
Producing a specularly reflecting
surface. |
|
Polycrystalline |
Comprising an aggregate of more than
one crystal, and usually a large number of crystals. |
|
Pop, Solvent |
Blister and/or void in the coating
resulting from trapped solvents released during curing process. |
|
Pot |
A vessel for holding molten metal.
Also used to refer to the electrolytic reduction cell employed in
winning certain metals, such as aluminum, from a fused electrolyte. |
|
Pouring |
The transfer of molten metal from the
ladle into ingot molds or other types of molds; for example, in
castings. |
|
Precipitation Hardening |
- Hardening caused by the
precipitation of a constituent form a supersaturated solid
solution.
- A process of hardening an alloy in
which a constituent precipitates from a supersaturated solid
solution.
|
|
Precipitation Heat Treatment |
Nonfer met. Any of the various aging
treatments conducted at elevated temperatures to improve certain of
the mechanical properties through precipitation from solid solution. |
|
Preferred Orientation |
A condition of a polycrystalline
aggregate in which the crystal orientations are not random. |
|
Preheating |
Nonfer. met.-Heating a metal to a
relatively high temperature for a relatively long time in order
to change the structure before working. Ingots are homogenized
by preheating.
|
|
Primary Crystal |
The first type of crystal that
separates from a melt during solidification. |
|
Proof Stress |
- The stress that will cause a
specified small permanent set in a material.
- A specified stress to be applied
to a member or structure to indicate its ability to withstand
service loads.
|
|
Propertional Limit |
- The greatest stress that the
material is capable of sustaining without a deviation from the
law of proportionally of stress to strain (Hooke's Law).
- The maximum stress at which strain
remains directly propertional to stress.
|
|
Published Tolerance |
A term sometimes used synonymously
with "Standard Tolerances". The term "Standard
Tolerance" is preferred. |
