Plasma arc cutting and gouging

Question 1

What is plasma

Answer 1

plasma is a gas that has been heated to extreme temp by an electric arc.

Question 2

in plasma arc cutting, plasma is the
A tungsten electrode
B electrons traveling across the arc
C ionized gas
D outer shielding gas

Answer 2

ionized gas

Question 3

The plasma arc cutting process
A can only be used on materials 6.4mm thick or less
B can only be used on mild steel and stainless steal
C is used on materials that are electrically conductive
D is used mainly to clean up foundry spills

Answer 3

is used on materials that are electrically conductive

Question 4

list 5 safety hazards associated with plasma arc cutting

Answer 4

Electric shock 
fumes
noise 
radiation
gases

Question 5

any available welding power source may be used for PAC true or false

Answer 5

False

Question 6

what are the functions of the plasma cutting torch

Answer 6

the plasma cutting torch functions are too current to an electrode, supply a flow of orifice gas to the contact nozzle and supply secondary shelving gas.

Question 7

compressed air is. generally used for PAC on which materials 
A carbon steels
B Cooper alloys 
C magnesium 
D titanium

Answer 7

Carbon steel

Question 8

What effect does improper PAC standoff distances have?

Answer 8

improper PAC standoff distances result in poor quality cuts, excessive nozzle wear and slow cutting speed

Question 9

what type of power source is required for CAC-A

Answer 9

either AC or DC

Question 10

what is the purpose of compressed air wit CAC-A

Answer 10

to remove molten metal

Question 11

list 3 metals that give off toxic fumes when cut with the CAC-A process

Answer 11

beryllium
cadmium
lead

Question 12

name the major components of the manual CAC-A electrode holder

Answer 12

the electrode holder are the power cable. the means to grip the electrode and the air passages and orifices to direct the air stream

Question 13

electrodes for CAC-A are usually made of?

Answer 13

graphic and carbon

Question 14

what is the maximum length that a CAC-A electrode should extend from the holder to the workpiece when gouging Carbon steel

Answer 14

180mm 7 inc

Question 15

What is the range of air pressure normally used for CAC-A

Answer 15

the range of air pressure for CAC-A is 550 KPA to 700 KPA 80 psi to 100 psi

Question 16

how are the air jets positioned when air carbon arc gouging in the flat position

Answer 16

toward the work, below the electrode

Question 17

how can you reduce carbon deposits on the joint surface when used CAC-A

Answer 17

use the proper air velocity and electrode movement. maintain a short arc without touching the electrode to the work without an air supply

Question 18

when is the surface hardening a problem when using CAC-A

Answer 18

when working on high carbon steels and cast irons

Question 19

with CAC-A when excessive slag adheres to the edges of the cut what is the likely cause?

Answer 19

Air pressure is to low