Deck 28: Weldability of Metals

Question 1

Preheating a part before starting the weld reduces the stress caused by the weld and helps the filler metal flow.

Answer 1

True

Question 2

The lower the carbon content of the metal, the more difficult it is to weld the steel.

Answer 2

False

Question 3

____ cast iron is the most widely used type of cast iron. It is easily welded but because it is somewhat porous it can absorb oils into the surface, which must be baked out before welding.

A) Malleable
B) Alloy
C) Gray
D) White

Answer 3

C

Question 4

____ cast iron is the hardest and most brittle of the cast irons because almost all of the carbon atoms are combined with the iron atoms.

A) White
B) Gray
C) Alloy
D) Malleable

Question 5

For steels containing more than ____ carbon, preheating and subsequent heat treatment are generally required to produce a satisfactory weld.

A) 0.10%
B) 0.20%
C) 0.30%
D) 0.40%

Question 6

Welding stresses occur because as metal is heated and cooled, it expands and contracts.

Question 7

The major purpose of preheating and postheating of cast iron is to control the rate of temperature change.

Question 8

____ stainless steels are used for ornamental or decorative applications such as architectural trim and at elevated temperatures for heat exchanging.

A) Martensitic
B) Ferritic
C) Austenitic
D) Precipitation hardening

Question 9

The ____ group of stainless steels is by far the most common.

A) austenitic
B) ferritic
C) martensitic
D) precipitation hardening

Question 10

Preheating is required any time that the metal to be welded is below 30 degrees F because the cold metal quenches the weld.

Question 11

Since ____ stainless steels are not hardenable by quenching, the weld can be cooled using a chill plate.

A) ferritic
B) martensitic
C) precipitation hardening
D) austenitic

Question 12

____ stainless steels are low in nickel. They are used in applications requiring both wear resistance and corrosion resistance.

A) Austenitic
B) Ferritic
C) Precipitation hardening
D) Martensitic

Question 13

To weld stainless steels, the arc should be as long as possible.

Question 14

A number of small welds are better than one or two large welds because the small welds do not have as much stress and are less likely to cause postweld cracking.

Question 15

In welding with the metal arc process, alternating current is more widely used than direct current.

Question 16

If you are not sure which filler metal to use, a good general rule is that a lower strength or grade can be used successfully, but a little stronger or higher grade seldom works.

Question 17

The closer the characteristics of the deposited metal match those of the material being welded, the better is the corrosion resistance of the welded joint.

Question 18

____ cast iron has alloying elements such as chromium, copper, manganese, molybdenum, or nickel added to obtain special properties.

A) Malleable
B) Gray
C) White
D) Alloy

Question 19

The fractured surface of ____ cast iron has a light, almost white, thin rim around the dark gray center.

A) gray
B) malleable
C) white
D) alloy

Question 20

The welding of ____ steels, having 0.30 to 0.50% carbon content, is best accomplished by the various fusion processes, depending upon the carbon content of the base metal.

A) low carbon
B) mild
C) medium carbon
D) high carbon

Question 21

The term ____________________ has been coined to describe the ease with which a metal can be welded properly.

Question 22

Steels alloyed with carbon and only a low concentration of silicon and manganese are known as ____________________.

Question 23

____________________ stainless steels can be much stronger than the austenitic, without losing toughness.

Question 24

The letter ____________________ in the AISI system, if used, indicate the manufacturing process basic open-hearth or electric furnace steel and basic oxygen furnace steel.

Question 25

The letter ____________________ in the AISI system, if used, indicate the manufacturing process electric furnace alloy steel.