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Machinability |
- The relative ease of machining a
metal.
- The capacity of a material to be
machined easily.
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Machinability Index |
A relative measure of the
machinability of an engineering material under specified standard
conditions. |
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Macroetch Test |
Consists of immersing a carefully
prepared section of the steel in hot acid and of examining the
etched surface to evaluate the soundness and homogeneity of the
product being tested. |
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Macroetching |
Etching of a metal surface with the
objective of accentuating gross structural details, for observation
by the unaided eye or at magnifications not exceeding ten diameters. |
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Macrograph |
- A graphic reproduction of a
prepared surface of a specimen at a magnification not exceeding
ten diameters. When photographed, the reproduction is known as a
photomacrograph (not a macrophotograph).
- A photographic reproduction of any
object that has not been magnified more than ten times.
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Macroscopic |
Visible either with the naked eye or
under low magnification (as great as about ten diameters. |
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Macrostructure |
- The structure of a metal as
revealed by examination of the etched surface at a magnification
not exceeding ten diameters.
- The structure of metal as revealed
by macroscopic examination.
- The structure of metals as
revealed by examination of the etched surface of a polished
specimen at a magnification not exceeding ten diameters.
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Malleability |
The property that determines the ease
of deforming a metal when the metal is subjected to rolling or
hammering. The more malleable metals can be hammered or rolled into
thin sheet more easily than others. |
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Manual Welding |
Welding where in the entire welding
operation is performed and controlled by hand. |
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Mark |
Damage in the surface of the product
whose name is often described by source. |
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Mark, Arbor |
Surface damage in the vicinity of a
coil ID caused by contact with a roughened, damaged or non-circular
arbor. |
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Mark, Bite |
A line which is generally
perpendicular to the rolling direction. |
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Mark, Bristle |
Raised surface about one inch long,
crimped wire shaped and oriented in any direction. |
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Mark, Chatter (Roll or Leveller) |
Numerous intermittent lines or
grooves that are usually full width and perpendicular to the rolling
or extrusion direction. |
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Mark, Drag |
A surface area showing a scratch or
abrasion resulting from contact of the hot extrusion with the press
equipment or tooling or, in the case of multi-hole dies, with others
sections as they exit the press. Also referred to as "Rub,
Tool." |
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Mark, Handling |
- For rolled products, an area of
broken surface that is introduced after processing. The mark
usually has no relationship to the rolling direction.
- For extrusions, damage that can be
imparted to the surface during handling operations.
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Mark, Heat Treat Contact |
Brownish, iridescent, irregularly
shaped stain with a slight abrasion located somewhere within the
boundary of the stain. It is a result of metal-to-metal contact
during the quenching of solution heat-treated flat sheet or plate. |
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Mark, Inclusion |
Appearance of surface where actual
inclusion or the void it left is observed. |
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Mark, Knife |
A continuous scratch (which may also
be creased) near a slit edge, caused by sheet contacting the slitter
knife. |
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Mark, Metal-on-Roll |
Repeating depression caused by a
particle adhering to a rotating roll over which the metal has
passed. Also referred to as "Dent, Repeating." |
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Mark, Pinch |
A sharp deviation from flat in the
sheet which is transferred from processing equipment subsequent to
the roll bite. Also referred to as "Crease." |
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Mark, Roll |
- For rolled products, a small
repeating raised or depressed area caused by the opposite
condition on a roll. The repeat distance is a function of the
offending roll diameter.
- For extrusions, a longitudinal
groove or indentation caused by pressure from contour rolls as a
profile (shape) passes through them for dimensional correction.
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Mark, Roll Bruise |
A greatly enlarged roll mark whose
height or depth is very shallow. See also "Mark, Roll." |
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Mark, Roll Skid |
A full width line perpendicular to
the rolling direction and repeating as a function of a work roll
diameter. |
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Mark, Rub |
A large number of very fine scratches
or abrasions. A rub mark can occur by metal-to-metal contact,
movement in handling and movement in transit. |
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Mark, Stretcher Jaw |
A cross hatched appearance left by
jaws at the end(s) of metal that has been stretched. These marks are
seen if insufficient metal has been removed after the stretching
operation. |
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Mark, Tail |
A greatly enlarged roll mark whose
height or depth is very shallow. Also referred to as "Mark,
Roll Bruise." |
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Mark, Take Up |
A short longitudinal indentation
parallel to the rolling direction. Also referred to as
"Scratch, Tension." |
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Mark, Traffic |
Abrasion which results from relative
movement between contacting metal surfaces during handling and
transit. A dark color from the abrasively produced aluminum oxide is
usually observed. A mirror image of a traffic mark is observed on
the adjacent contacting surface. |
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Mark, Whip |
A surface abrasion which is generally
diagonal to the rolling direction. It is caused by a fluttering
action of the metal as it enters the rolling mill. |
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Master Alloy |
An alloy containing at least some
aluminum and one or more added elements for use in making alloying
additions to molten aluminum. Also referred to as
"Hardener." |
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Master/Parent Coil |
A large coil to be slit into two or
more smaller coils to meet customer width requirements. |
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Master/Parent Plate |
A large plate product to be sheared
or sawn into two or more smaller plates to meet customer width and
length requirements. |
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Matrix |
- The principal phase or aggregate
in which another constituent is embedded.
- The principal phase in which
another constituent is embedded.
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Mechanical Polishing |
A method of producing a specularly
reflecting surface by use of abrasives. |
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Mechanical Properties |
- The properties of a material that
reveal its elastic and inelastic behavior where force is
applied, thereby indicating its suitability for mechanical
application; for example, modulus of elasticity, tensile
strength, elongation, hardness, and fatigue limit.
- Those properties of a materiel
that reveal the elastic and inelastic reaction when force is
applied, or that involve the relationship between stress and
strain; for example, the modulus of elasticity, tensile strength
and fatigue limit. These properties have often been designated
as physical properties, but the term mechanical properties is
much to be preferred. The mechanical properties of steel are
dependent on its microstructure.
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Mechanical Working |
Plastic deformation or other physical
change to which metal is subjected, by rolling, hammering, drawing.,
etc. to change its shape, properties or structure. |
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Melting Point |
The temperature at which a pure
metal, compound or eutectic changes form solid to liquid; the
temperature at which the liquid and the solid are in equilibrium. |
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Melting Range |
The range of temperature in which an
alloy melt; that is the range between solidus and liquidus
temperatures. |
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Metal |
An opaque, lustrous, elemental
substance that is a good conductor of heat and electricity and, when
polished, a good reflector or light. Most metals are malleable and
ductile and are, in general, denser than other substances. |
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Metallography |
The science concerning the
constituents and structure of metals and alloys as revealed by the
microscope. |
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Metallograph |
An optical instrument designed for
both visual observation and photomicrography of prepared surfaces of
opaque materials at magnifications ranging from about 25 to about
1500 diameters. |
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Metastable |
Possessing a state of
pseudo-equilibrium that has a free energy higher than that of the
true equilibrium state but from which a system does not change
spontaneously. |
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Microcrack |
A crack of microscopic size. |
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Micrograph |
A graphic reproduction of the
prepared surface of a specimen at a magnification greater than ten
diameters. When photographed, the reproduction is known as a
photomicrograph (not a microphotograph). |
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Microstructure |
- The structure of a prepared
surface of a metal as revealed by a microscope at a
magnification greater than ten diameters.
- The structure of polished and
etched metal and alloy specimens as revealed by the microscope.
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Mill Edge |
The edge of strip, sheet or plate in
the as rolled state. Unsheared. |
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Mill Finish |
A surface finish produced on sheet
and plate. Characteristic of the ground finish used on the rolls in
fabrication. |
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Mill Finish Sheet |
Sheet having a nonuniform finish
which may vary from sheet to sheet and within a sheet and may not be
entirely free from stains or oil. |
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Minimum Residual Stress (MRS) |
The term applies to products, usually
flat rolled, which have been processed to minimize internal stress
of the kind that causes distortion when material is
disproportionally removed from one of the two surfaces through
mechanical or chemical means. |
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Modulus of Elasticity |
A measure of the rigidity of metal.
Ratio of stress, within proportional limit, to corresponding strain.
Specifically, the modulus obtained in tension or compression is
Young's modulus, stretch modulus or modulus of extensibility; the
modulus obtained in torsion or shear is modulus of rigidity, shear
modulus or modulus of torsion; the modulus covering the ratio of the
mean normal stress to the change in volume per unit volume is the
bulk modulus. The tangent modulus and secant modulus are not
restricted within the proportional limit; the former is the slope of
the stress-strain curve at a specified point; the latter is the
slope of a line from the origin to a specified point on the
stress-strain curve. Also called elastic modulus and coefficient of
elasticity. |
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Modulus of Elasticity (tension) |
Force which would be required to
stretch a substance to double its normal length, on the assumption
that it would remain perfectly elastic, i.e., obey Hooke's Law
throughout the twist. The ratio of stress to strain within the
perfectly elastic range. |
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Modulus of Rigidity |
The ratio of the unit shear stress in
a torsion test, to the displacement caused by it per unit length in
the elastic range. This modulus corresponds to the modulus of
elasticity in tension test. |
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Mold |
A form of cavity into which molten
metal is poured to produce a desired shape. |
