Section 11.4- Iron Flashcards

1
Q

the fourth most abundant element found in the earth’s crust

A

iron

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2
Q

second most abundant metal

A

iron

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3
Q

iron occurs in the crust in several ores, such as

A

hematite, magnetite, siderite, pyrite

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4
Q

iron is soft and silvery white as a pure metal; in moist air it quickly reacts with oxygen (rusts) to form reddish-brown

A

iron (III) oxide

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5
Q

since the Middle Ages, the primary method of reducing iron ore to iron metal has been the _________________

a structure consisting of a vertical, heat-resistant furnace column, filled with ore and fuel, in which the chemical reactions take place

A

blast furnace

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6
Q

coke is another name for

A

carbon

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7
Q

calcium silicate (CaSiO3) mixes with other impurities to form

is less dense than iron and floats upon it, preventing the reaction of incoming air with molten iron

A

slag

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8
Q

the molten iron is __________________ (drained from the furnace) through a duct near the furnace’s base

A

tapped

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9
Q

once molten iron is tapped, it is called

A

pig iron

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10
Q

if pig iron is cast into molds and cooled, it is known as

A

cast iron

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11
Q

a fluffy insulation material called _______________ is produced from slag if jets of steam are blown through the molten slag as it cools

A

mineral wool

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12
Q

alternate method of iron reduction in which natural gas is used to reduce iron ore to sponge iron

A

direct iron reduction

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13
Q

a solid, powdery form of iron suitable for steelmaking

A

sponge iron

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14
Q

the most commonly used form of iron

an alloy of iron and a small percentage of carbon

A

steel

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15
Q

carbon steel with less that .2% carbon that is ductile and malleable

A

mild steel

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16
Q

carbon steel with .2% to .6% of carbon

A

medium steel

17
Q

carbon steel that contains between .6% and 1.5% of carbon

A

high-carbon steel

18
Q

steels that contain other metals besides iron

A

alloy steels

19
Q

contain a total of 1% to 5% of other alloying metals

A

low-alloy metals

20
Q

contain more than 5% of one or more alloying elements in steel

A

high-alloy steels

21
Q

a high-alloy steel that is resistant to corrosion

A

stainless steel

22
Q

pig iron from blast furnaces is typically refined to steel by the

A

basic oxygen process

23
Q

about 60% of steel production in the United States uses the

A

electric-arc furnace

24
Q

steel production process in which an electric arc between giant carbon electrodes provides the heat to melt the metal

A

electric arc furnace

25
Q

higher temperature is possible with the _________________ than the _____________________ (two processes of steel production)

A

electric-arc= higher temps
basic oxygen= lower temps

26
Q

internals stresses and distortions in the metal after it cools can be removed by a process called ________________

heats the steel to 700 C - 800C for up to several hours and then is slowly cooled

27
Q

one of the simplest ways to harden a piece of steel

when the metal is bent or hammered into its final shape at relatively low temps

A

cold working

28
Q

one of the most common examples of cold working is _________, in which a piece of solid steel is stamped into its final shape by a giant, hammerlike press

A

cold forging

29
Q

examples of cold working

A
  1. cold forging- hammerlike press
  2. cold-rolling- heavy rollers
  3. drawing- pulled through small hole
30
Q

way in which the hardness of a piece of steel may be altered is

cooling red-hot metal quickly

31
Q

if the steel is too brittle after quenching, it may be made less brittle by a process called

steel GENTLY heated to a MODERATE temperature and then allowed to cool

32
Q

in cases where both toughness and hardness are desired, a process called __________________ can be used to harden the surface of the steel while leaving the interior resilient

A

case hardening

33
Q

alloys of carbon and iron ONLY, containing varying percentages of carbon that are determined by the properties desired

A

carbon steels