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Heat Treatment Requirements
Ladle Analysis
A term applied to the chemical analysis representative of a heat of steel as
reported by the producer. It is determined by analyzing a test ingot sample
obtained during the pouring of the steel from a ladle.
Lamellar Tear
A system of cracks or discontinuities aligned generally parallel to the worked
surface of a plate. Usually associated with a fusion weld in thick plate.
Lamination
An abnormal structure resulting in a separation or weakness aligned generally
parallel to the worked surface of the metal.
Laminations
A defect appearing in sheets or strips as a segregation or in layers. To become
divided, caused by gas pockets in the ingot.
Laminations
Metal defects with separation or weakness generally aligned parallel to the
worked surface of the metal. May be the result of pipe, blisters, seams,
inclusions, or segregation elongated and made directional by working. Lamination
defects may also occur in metal-powder compacts.
Lap
A surface defect, appearing as a seam, caused by fording over hot metal, fins,
or sharp corners and then rolling or forging them into the surface, but not
welding them.
Lap
A surface defect appearing as a seam, caused by folding over hot metal, fins or
sharp corners and then rolling or forging them into the surface, but not welding
them.
Lap-Weld
A term applied to a weld formed by lapping two pieces of metal and then pressing
or hammering, and applied particularly to the longitudinal joint produced by a
welding process for tubes or pipe, in which the edges of the skelp are beveled
or scarfed so that when they are overlapped they can be welded together.
Lath Martensite
Martensite formed, partly in steel containing less than about 1.0% C and solely
in steels containing less than about 0.5% C, as parallel arrays or packets of
lath-shape units about 0.1 to 0.3 m thick, and having a habit plane that is
close to {111}.
Lattice
Space lattice. Lattice lines and lattice planes are lines and planes chosen so
as to pass through collinear lattice points, and non-collinear lattice points,
respectively.
Leveling
Flattening rolled metal sheet or strip.
Light Metal
One of the low-density metals such as aluminum, magnesium, titanium, beryllium,
or their alloys.
Light Metals
Metal and alloys that have a low specific gravity, such as beryllium, magnesium
and aluminum.
Liquation
Partial melting of an alloy.
Liquidus
In a constitutional diagram, the locus of points representing the temperatures
at which various components commence freezing on cooling or finish melting on
heating.
Lithographic Sheet Aluminum
Sheet having a superior surface on one side with respect to freedom from surface
imperfections and supplied with a maximum degree of flatness, for use as a plate
in offset printing.
Long Terne
A term applying to steel sheets that have been terne coated (Lead and Tin) by
immersion in a bath of Terne Metal.
Longitudinal Direction
The principal direction of flow in a worked metal.
Low Brass
80% cu. A copper-Zinc alloy containing 20% zinc. Is a light golden color, very
ductile, suitable for cupping, drawing, forming, etc. Because of its good
strength and corrosion resistance it is used for flexible metal gose, metal
bellows, etc.
Low Carbon Steels
Contain from 0.10 to 0.30% carbon and less than 0.60% manganese. (The product of
Basic Oxygen, Bessemer, Open Hearth or Electric Processes.)
Low-Hydrogen Electrode
A covered arc-welding electrode that provides an atmosphere around the arc and
molten weld metal which is low in hydrogen.
Luders Lines (Steel)
(Characteristic of No. 5 Yemper-Not a defect in No. 5 dead soft temper.) Long
vein-like marks appearing on the surface of certain metals, in the direction of
the maximum shear stress, when the metal is subjected to deformation beyond the
field point.
Luders Lines or Bands
Elongated surface markings or depressions caused by localized plastic
deformation that results form discontinuous (inhomogeneous) yielding.