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.)

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.

An abnormal structure resulting in a separation or weakness aligned generally parallel to the worked surface of the metal.

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.

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}.

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)

The width of a fusion face in a fillet weld.

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.

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.

Partial melting of an alloy.

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.

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.

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.