L
Lack of fusion
Lack of union in a weld (Between weld metal and parent
metal, parent metal and parent metal or between weld metal
and weld metal.)
LCH The London Clearing House.
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.
Ladle Metallurgy Furnace (LMF)
An intermediate steel processing unit that further refines the chemistry and
temperature of molten steel while it is still in the ladle. The ladle metallurgy
step comes after the steel is melted and refined in the electric arc or basic
oxygen furnace, but before the steel is sent to the continuous caster.
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.
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.
Lapped Welds
A defect in the butt weld where the strip overlays.
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.
Lead Annealing
(See Bath Annealing)
Leftward welding
A gas welding technique in which the flame is (Forward welding)
Leg
The width of a fusion face in a fillet weld.
Leveling
A mechanical process in which the strip is stretched beyond its yield point by
bending over small diameter rolls. The purpose is to improve the flatness of
characteristics of the strip.
Flattening rolled metal sheet or strip. (See Roller and Stretcher
Leveling)
Leveling Line
A process to flatten any shape deficiencies (wavy edges and buckles) in the
sheet, prior to final shipment. Most cold-rolled sheet initially has a crowned
cross-section that, if such a shape is undesirable to the customer, must be
flattened in the leveling line.
Life Cycle Costing
An accounting method of costing where expenses are allocated over the life of
the product. Life cycle costs are often lower for stainless steel than for
alternatives despite a higher initial outlay, because stainless products
generally last longer and require little maintenance.
Light Metals
Metal and alloys that have a low specific
gravity, such as beryllium, magnesium and aluminum.
Light-Gauge Steel
Very thin steel sheet that has been temper-rolled or passed through a
cold-reduction mill. Light gauge steel normally is plated with tin or chrome for
use in food containers.
Limestone
Used by the steel industry to remove impurities from the iron made in blast
furnaces. Magnesium-containing limestone, called dolomite, is also sometimes
used in the purifying process.
Line Pipe
Pipe used in the surface transmission of oil, natural gas and other fluids.
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 An open position for the purchase of metal.
Long Products
Classification of steel products that includes bar, rod and structural products,
that are "long", rather than "flat".
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.
Looper
An accumulator where extra strip is stored momentarily to keep the center
section of the line running continuously.
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 Steel
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.)
Steel with less than 0.005% carbon is more ductile (malleable): It is capable of
being drawn out or rolled thin for use in automotive body applications. Carbon
is removed from the steel bath through vacuum degassing.
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 or Bands
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.
Elongated surface markings or depressions
caused by localized plastic deformation that results form discontinuous
(inhomogeneous) yielding.
Luster Finish
Refer to Finish.
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