[机] 沼铁矿

Iron \I"ron\ ([imac]"[u^]rn), n. [OE. iren, AS. [=i]ren,
[=i]sen, [=i]sern; akin to D. ijzer, OS. [=i]sarn, OHG.
[=i]sarn, [=i]san, G. eisen, Icel. [=i]sarn, j[=a]rn, Sw. &
Dan. jern, and perh. to E. ice; cf. Ir. iarann, W. haiarn,
Armor. houarn.]
1. (Chem.) The most common and most useful metallic element,
being of almost universal occurrence, usually in the form
of an oxide (as hematite, magnetite, etc.), or a hydrous
oxide (as limonite, turgite, etc.). It is reduced on an
enormous scale in three principal forms; viz., {cast
iron}, steel, and {wrought iron}. Iron usually appears
dark brown, from oxidation or impurity, but when pure, or
on a fresh surface, is a gray or white metal. It is easily
oxidized (rusted) by moisture, and is attacked by many
corrosive agents. Symbol Fe (Latin Ferrum). Atomic number
26, atomic weight 55.847. Specific gravity, pure iron,
7.86; cast iron, 7.1. In magnetic properties, it is
superior to all other substances.

Note: The value of iron is largely due to the facility with
which it can be worked. Thus, when heated it is
malleable and ductile, and can be easily welded and
forged at a high temperature. As cast iron, it is
easily fusible; as steel, is very tough, and (when
tempered) very hard and elastic. Chemically, iron is
grouped with cobalt and nickel. Steel is a variety of
iron containing more carbon than wrought iron, but less
that cast iron. It is made either from wrought iron, by
roasting in a packing of carbon (cementation) or from
cast iron, by burning off the impurities in a Bessemer
converter (then called Bessemer steel), or directly
from the iron ore (as in the Siemens rotatory and
generating furnace).

2. An instrument or utensil made of iron; -- chiefly in
composition; as, a flatiron, a smoothing iron, etc.

My young soldier, put up your iron. --Shak.

3. pl. Fetters; chains; handcuffs; manacles.

Four of the sufferers were left to rot in irons.
--Macaulay.

4. Strength; power; firmness; inflexibility; as, to rule with
a rod of iron.

5. (Golf) An iron-headed club with a deep face, chiefly used
in making approaches, lifting a ball over hazards, etc.
[Webster 1913 Suppl.]

{Bar iron}. See {Wrought iron} (below).

{Bog iron}, bog ore; limonite. See {Bog ore}, under {Bog}.

{Cast iron} (Metal.), an impure variety of iron, containing
from three to six percent of carbon, part of which is
united with a part of the iron, as a carbide, and the rest
is uncombined, as graphite. It there is little free
carbon, the product is {white iron}; if much of the carbon
has separated as graphite, it is called {gray iron}. See
also {Cast iron}, in the Vocabulary.

{Fire irons}. See under {Fire}, n.

{Gray irons}. See under {Fire}, n.

{Gray iron}. See {Cast iron} (above).

{It irons} (Naut.), said of a sailing vessel, when, in
tacking, she comes up head to the wind and will not fill
away on either tack.

{Magnetic iron}. See {Magnetite}.

{Malleable iron} (Metal.), iron sufficiently pure or soft to
be capable of extension under the hammer; also, specif., a
kind of iron produced by removing a portion of the carbon
or other impurities from cast iron, rendering it less
brittle, and to some extent malleable.

{Meteoric iron} (Chem.), iron forming a large, and often the
chief, ingredient of meteorites. It invariably contains a
small amount of nickel and cobalt. Cf. {Meteorite}.

{Pig iron}, the form in which cast iron is made at the blast
furnace, being run into molds, called pigs.

{Reduced iron}. See under {Reduced}.

{Specular iron}. See {Hematite}.

{Too many irons in the fire}, too many objects or tasks
requiring the attention at once.

{White iron}. See {Cast iron} (above).

{Wrought iron} (Metal.), the purest form of iron commonly
known in the arts, containing only about half of one per
cent of carbon. It is made either directly from the ore,
as in the Catalan forge or bloomery, or by purifying
(puddling) cast iron in a reverberatory furnace or
refinery. It is tough, malleable, and ductile. When formed
into bars, it is called {bar iron}.