Chapter L: L Luster

L

ladle

A refractory-lined receptacle equipped with a spout used for transporting molten metal from the furnace to ingot molds, from which it is poured. Large ladles may contain lugs for handling by a crane.

lamination

Metal defects involving the separation of two or more layers, sometimes found in wrought, rolled, or forged metals. These separations are generally aligned parallel to the worked surface and may be the result of nonmetallic inclusions, segregation elongated and made directional by working.

land

(1) A drill term used to describe the peripheral portion of the drill body between adjacent flutes; (2) a gear term: the top land is the top surface of a tooth, and the bottom land is the surface of the gear between the fillets of adjacent teeth.

land width

A drill term used to describe the distance between the leading edge and the heel of the land measured at a right angle to the leading edge.

lanthanum

CAS number 7439-91-0. Soft, malleable, lustrous, silvery-white or gray metal. An alloying element. One of the most-abundant rare-earth metals. Decomposes in cold water, slowly producing lanthanum hydroxide and flammable hydrogen gas. Danger: Pyrophoric, the finely divided material will catch fire at room temperature.

Symbol: La	Density (g/cc): 6.15
Physical state: Gray solid	Specific heat: 6.65
Periodic Table Group: IIIB	Melting point: 1,688 F/920 C
Atomic number: 57	Boiling point: 6,267 F/3,464 C
Atomic weight: 138.9055	Source/ores: Monazite sand, bastnasite, seawater
Valence: 3