Section 11.4- Iron

Question 1

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

Answer 1

iron

Question 2

second most abundant metal

Answer 2

iron

Question 3

iron occurs in the crust in several ores, such as

Answer 3

hematite, magnetite, siderite, pyrite

Question 4

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

Answer 4

iron (III) oxide

Question 5

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

Answer 5

blast furnace

Question 6

coke is another name for

Answer 6

carbon

Question 7

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

Answer 7

slag

Question 8

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

Answer 8

tapped

Question 9

once molten iron is tapped, it is called

Answer 9

pig iron

Question 10

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

Answer 10

cast iron

Question 11

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

Answer 11

mineral wool

Question 12

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

Answer 12

direct iron reduction

Question 13

a solid, powdery form of iron suitable for steelmaking

Answer 13

sponge iron

Question 14

the most commonly used form of iron

an alloy of iron and a small percentage of carbon

Answer 14

steel

Question 15

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

Answer 15

mild steel

Question 16

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

Answer 16

medium steel

Question 17

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

Answer 17

high-carbon steel

Question 18

steels that contain other metals besides iron

Answer 18

alloy steels

Question 19

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

Answer 19

low-alloy metals

Question 20

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

Answer 20

high-alloy steels

Question 21

a high-alloy steel that is resistant to corrosion

Answer 21

stainless steel

Question 22

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

Answer 22

basic oxygen process

Question 23

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

Answer 23

electric-arc furnace

Question 24

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

Answer 24

electric arc furnace

Question 25

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

Answer 25

electric-arc= higher temps basic oxygen= lower temps

Question 26

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

Answer 26

annealing

Question 27

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

Answer 27

cold working

Question 28

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

Answer 28

cold forging

Question 29

examples of cold working

Answer 29

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

Question 30

way in which the hardness of a piece of steel may be altered is cooling red-hot metal quickly

Answer 30

quenching

Question 31

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

Answer 31

tempering

Question 32

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

Answer 32

case hardening

Question 33

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

Answer 33

carbon steels