Chapter 7,8,9

Question 0

When molten iron is slowly cooled and the material begins to solidify, the branches that start to grow are

Answer 0

Dendrites

Question 1

Fundamental arrangement of atoms in a space lettuce is known as

Answer 1

Unit cell

Question 2

Which of the following structures of iron has a face centered cubic space lattice

Answer 2

Austenitic iron

Question 3

Which of the following structures of iron has a body centered cubic space lattice

Answer 3

Ferrite

Question 4

How many atoms are in the unit cell of a body centered tetragonal space lattice

Answer 4

Nine

Question 5

How many atoms are in the unit cell of a close packed hexagonal space lattice

Answer 5

17 total atoms

Question 6

A material with the large grain size is normally

Answer 6

Ductile

Question 7

The point at which ferritin iron starts to change to Austenitic during the heating cycle is known as the blank transformation temperature

Answer 7

Lower

Question 8

Ferrite are normally has _______ then Martensitic iron

Answer 8

Ductility

Question 9

Structure of iron at room temperature that contains 6.67% carbon. Assume that this metal has never been heat treated.

Answer 9

Cementite

Question 10

Name the structure of a solid solution of steel at room temperature that contains 0.8% carbon. Assume that this steel has never been heat treated.

Answer 10

Pearlite

Question 11

Approximately how much carbon is in a sample of pure pearlite?

Answer 11

0.8%

Question 12

What is austenite?

Answer 12

Steel that occurs only at elevated temperatures

Question 13

What structural change occurs when steel is slowly cooled from a high temperature to room temperature?

Answer 13

It changes from face-centered cubic back to body-centered cubic.

Question 14

Of the following types of iron-carbon, which is the hardest: Austenite, Cementite, Ferrite, and Martensite?

Answer 14

Martensite

Question 15

Iron at 1800 F is rapidly quenched in water. What structural form of iron-carbon is the most predominant in the result if the alloy contains 0.9% carbon?

Answer 15

Martensite

Question 16

Assume a sample of steel is cooled from an elevated temperature to 1200F and contains a very small percentage of carbon (perhaps 0.2%) The steel has not been previously heat treated. Name the new structural form of the solid solution of this steel.

Answer 16

Ferrite and Pearlite

Question 17

Assume a sample of steel has been rapidly quenched from an elevated temperature to room temperature. It contains 0.8% carbon. Name the structural form of the solid solution of this steel.

Answer 17

Martensite

Question 18

What point on an iron carbon phase diagram marks the intersection of the upper transformation temperature line, the lower transformation temperature line. and the pure pearlite line?

Answer 18

at 1300F at 0.8% carbon (Eutectoid Point)