Chapter 21 GTAW

Question 1

What is a weld pool?

Answer 1

A small, melted area of the base metal.

Question 2

What is a filler metal?

Answer 2

A metal or alloy added to the base metal to create a weld, braze or solder joint

Question 3

Usually a filler metal with a similar composition to the _____________ is used.

Answer 3

base metal

Question 4

What would happen if the rod diameter is too small?

Answer 4

Metal will have to be added often, and the rod will be used up quiclkly

Question 5

What would happen if the rod diamter is too large?

Answer 5

Too much metal may be added. The large amount of filler metal will cool the weld pool causing bumps in the weld.

Question 6

What are the two ways to start or strike an arc?

Answer 6

1. Use a high frequency generator
2. touch the electrode to the base metal

Question 7

When using high frequency start, hold the electrode about _____ from the surface.

Answer 7

1/8” (3mm) above the base metal

Question 8

Touch starting is only used with ________ welding

Answer 8

DC

Question 9

When using the forehand welding method the travel angle is called a ____________.

Answer 9

push angle

Question 10

The torch is held at a __________ travel angle (push angle) using the ___________ method.

Answer 10

15°- 30°
forehand

Question 11

The electrode is held at a work angle of _____ which is _____________ to the work surface.

Answer 11

0°
perpendicular (90°)

Question 12

What should you do if you need more current (for more penetration or more heat) while welding?

Answer 12

you can increase the current by moving the electrode toward the base metal

Question 13

When welding a butt joint or a bead on a plate, hold the torch so it has a push angle, or travel angle of ______________, the work angle should be

Answer 13

15°-30°
0°

Question 14

When welding a fillet weld, the travel angle should be _______, the work angle should be _________.

Answer 14

15° - 30°
45°

Question 15

The rod end should be about ________ away from the pool to keep the filler metal protected by the shielding gas

Answer 15

1/8” - 3/16” (3mm - 5mm)

Question 16

After using a filler metal, release the foot pedal to stop the arc. Hold the torch in place so ________________

Answer 16

the shielding gas protects the electrode and weld while they are cooling

Question 17

What change is necessary if a c-shaped weld pool is not preset when making a fillet weld on a lap joint?

Answer 17

Often the edge will melt more than the surface. Point the torch more towards the surface to put more heat on to the surface and less on to the edge. Change the angle of the torch as needed so both pieces melt evenly.

Question 18

When is overlap caused?

Answer 18

When a large wled pool flow onto the base metal and becomes solid. The molten weld pool does not melt the base metal it just lies on top of it.

Question 19

How do you prevent overlap

Answer 19

• Keep the weld pool the proper size
• Use the correct rtoech angle
• do not add too much filler metal

Question 20

What three factors cause tungsten inclusions?

Answer 20

1. Dipping the electrode into the weld pool
2. using too much weld current
3. using an electrode that is too small

Question 21

What causes porosity?

Answer 21

When shilding gases do not protect the weld area.

Question 22

What is porosity?

Answer 22

The presence of gas pockets or voids in weld metal

Question 23

What are undercuts?

Answer 23

A depression at the weld toe indicating that the weld metal is below the level of the base metal.

Question 24

What causes undercutting?

Answer 24

By using incorrect torch angle