Chapter 4

Question 1

_______________ is an example of welding with heat and pressure

Answer 1

resistance spot welding (RSW)

Question 2

What is resistance spot welding (RSW)?

Answer 2

A resistance welding process used to join overlapping pieces of metal together by creating small spot welds between two electrodes.

Question 3

What is resistance welding (RW)?

Answer 3

It is a process that uses the resistance of metals to electrical flow as a source of heat for welding.

Question 4

No ______ is used in resistance welding. In these processes, high current is passed through the base metal. The base metal’s resistance to the current flow generates the ____________ needed to create the weld.

Answer 4

• filler metal
• heat

Question 5

A ________ metal is made of one substance. For example ___________

Answer 5

• pure
• iron, aluminum and nickle

Question 6

A ___________ is a metal with additional elements. The properties of the pure metals are improved by adding other elements.

Answer 6

metal alloy

Question 7

What are some examples of metal alloys?

Answer 7

low carbon steel
stainless steel

Question 8

_______________ properties determines how a material reacts with other materials

Answer 8

chemical

Question 9

What is corrosion resistance?

Answer 9

A material’s ability to withstand attack by corrosives such as acid and salt water.

Question 10

What is oxidation resistance?

Answer 10

A ability of a material to resist the formation of oxides. Metal oxides occur when oxygen is combined with metal.

Question 11

_______________ is ability of a material to withstand applied loads without failing.

Answer 11

strength

Question 12

_________________ is the ability of a material to resist pulling forces.

Answer 12

tensile strength

Question 13

_______________ is the ability of a material to resist pulling or crushing forces

Answer 13

compressive strength

Question 14

________ is the ability of a material to stretch or bend without breaking

Answer 14

ductility

Question 15

______________ is the inability of a material to resist fracturing.

Answer 15

Brittleness

Question 16

________ is the ability of a material to resist cracking and prevent a crack from expanding

Answer 16

toughness

Question 17

____________ is the ability of a material to resist indentations or scratching

Answer 17

hardness

Question 18

Welding a metal affects its _________ and _______ properties. Heat produced by welding creates stress in the metal.

Answer 18

chemical and mechanical

Question 19

What is stress?

Answer 19

An internal force within a metal, also the load imposed on an object.

Question 20

Heat affects the _______ and the _______ of the metal. If the metal was heat-treated before being welded the effects of heat treating are ___________ in the area around the weld.

Answer 20

ductility and toughness
lost

Question 21

True or False: When heat is applied to a metal, does the metal expand or increase in size?

Answer 21

True

Question 22

When heat is removed, metal cools and __________________

Answer 22

contracts or decreases in size

Question 23

True or False: Expansion and contraction does not affect the stress of the metal

Answer 23

False: Expansion and contraction creates stress in the metal

Question 24

Why does metal warp? Is it acceptable?

Answer 24

It does this to relief stress. In many welding applications deformation and movement is not acceptable. Welding jigs or fixtures are commonly used to keep parts from moving.

Question 25

What can you do to reduce or prevent movement and/or stress in the parts during welding?

Answer 25

1. Tack weld the parts 2. Align the parts to allow for contraction during welding 3. Use welding jogs or fixtures to clamp the pieces 4. Preheat the parts 5. Heat treat the welded parts 6. Use the proper welding procedure

Question 26

What is the purpose of preheating, interpass heating and some post-weld heat treating processes?

Answer 26

To reduce stress. High stress int he material may prevent the part from forming as intended.

Question 27

What is preheating?

Answer 27

A process that heats the metal to a specific temperature prior to a surfacing of welding operation. It also slows the cooling rate with produces less stress.

Question 28

What is interpass heating?

Answer 28

The heating of metal while it is being welded or between weld passes.

Question 29

______________ and __________ are heat treating processes in which a metal is heated and allowed to cool slowly.

Answer 29

Annealing and normalizing

Question 30

Annealing and normalizing steel involves heating the steel to ___________ degrees in an oven or furnace for a specific amount of time. In the normalizing process the steel is removed from the furnace and allowed to air-cool.

Answer 30

1400 °F -1670°F (760 °C to 910°C)

Question 31

What is stress-relieving?

Answer 31

It is a process used to to reduce stress and is similar to annealing except that lower temperatures are used.

Question 32

What is quenching?

Answer 32

Rapid cooling of metal in a heat-treating process as a means of hardening it

Question 33

What is tempering?

Answer 33

A heating process in which metal is heated to reduce hardness and improve toughness.

Question 34

When quenching and tempering, the steel is tempered by reheating it to ______ degrees and cooling it.

Answer 34

400°F- 1300°F (200°C to 700°C)

Question 35

______________ is the force that causes electrons to flow through a circuit.

Answer 35

Voltage

Question 36

What is Open circuit voltage (OCV)?

Answer 36

Voltage present in an electrical circuit even when no current is flowing.

Question 37

The _________ between the electrode and base metal offers resistance to the flow of electrons.

Answer 37

air gap

Question 38

____________ is the flow of electrons in an electrical circuit.

Answer 38

current

Question 39

Current is measured in _______ or ______. Current can be compared to the flow of water from a faucet.

Answer 39

amperes or amps