Carbon Arc Cutting (CAC– A) Flashcards
What type of eye protection must always be worn during carbon arc cutting
Safety glasses
what shade lens is recommended for CAC – A cutting at less than 500 Amps
12
True or false? Gouging is a very loud process
True
What is the most important thing in reducing the risk of electric shock when using CAC-A
Do not run cables through water, Keep electrodes and torches dry, and keep your gloves dry
What must you check before touching an electric shock victim
Make sure they are not still in contact of the circuit
Gouging can shoot sparks and molten metal up to?
6 m ( 20 ft)
Why do you not want to play spark shields too close to where you are working?
Sparks can bounce back and burn you
Combustible materials should be moved how many metres away
15 m (50ft)
What type of electrode is used in CAC – A?
Carbon
What type of power source is generally used with CAC-A?
Constant current
How many psi (kPa) is required for a gouging torch?
82-100 psi (551-689 kPa)
A medium duty torch uses how many cubic feet per minute (cam) of compressed air?
25 cfm (700L/m)
What can CAC-A be used to do?
Cut, gouge, & wash a surface
True or false? CAC-A is used for removing weld defects
True
True or false? CAC-A can be used to cut most types of ferrous and nonferrous metals
True
Which polarity is recommended for carbon and low alloy steel?
DCEP (direct current electrode positive)
Welding power sources used for CAC-A are recommended to have what percentage duty cycle?
100%
What is the minimum recommended open circuit voltage of a CAC-A?
60 V
Machine gouging with an automatic electrode feeder is typically done with what power source?
Constant voltage CV
True or false? DC electrodes can be used with AC power
False
When electrode diameter goes up what does amperage requirements do?
Increase
To connect two power sources together you must ensure what?
Ensure they are connected in parallel, ensure to follow the manufactures directions, and ensure they are identical. 
In CAC-A, what will insufficient air supply cause?
Carbon buildup
What gas can be used as an alternative to compressed air?
Nitrogen
Hoses and fittings for medium and heavy duty gouging must have an inside diameter of?
3/8 in (10mm)
What is the biggest difference between a SMAW and CAC-A electrode holder?
Air jet holes
Air jet holes are found?
Between the electrode and work peace
How many times should the electrode holder be examinated for wear and damage before use?
Daily
What size cable is commonly used for CAC-A?
4/0
CAC-A Electrode holders contain an electrical cable and what?
Air supply hose
True or false? Working above a cable rated capacity can cause overheating?
True
The workplace lead must be connected where?
As close to the work area as possible
Who is responsible to ensure equipment is safe to use?
Employee
What does the copper coating on DC copper coated electrodes do?
Improves electrode life, improves heat dissipation, and maintains the electrode shape
DC copper coated electrodes come in size ranging from 5/32 in (4mm) to?
1in (25.4 mm)
Uncoated electrodes are mainly used for?
Demolition
AC copper coated electrodes contain?
Arc stabilizers
CAC-A Electrodes come in how many different shapes?
4
Jointed electrodes are designed to?
Be joined together
True or false? Flat electrodes are usually used to remove weld reinforcement or backing material.
True
Groove width is usually how many inches larger than the electrode diameter?
1/8 in (3.2mm)
1/4 in diameter DC electrodes require 200 to how many amps?
400 amps
You should replace an electrode when it gets down to how many millimetres or inches long?
50mm or 2 inches
True or false? CAC-A stubs should not be thrown on the floor as they can cause a slipping hazard?
True
Is most CAC-A cutting done manually or by machine?
Manually
What do most CAC-A cutting machines consist stuff?
Motorized carriage, power supply, and track
How do fully automatic machine controlled electrodes feed rate?
By Sensing arc voltage or amperage
Electrode angle for cutting is almost what degree to the base metal?
90°
CAC-A is typically done with a pushing or pulling technique?
Pushing
What type of cut does a steeper electrode angle produce?
Deeper
What type of groove will a straight up and down electrode produce?
V-Shaped
Slower travel speed will produce a groove that is?
Deeper
What is the indicator for correct travel speed?
A steady hissing sound
True or false? Higher current settings produce larger grooves.
True
What do you do if you do not have enough air supply?
Decrease travel speed
Electrode stick out should be?
4-6 in (101-152mm)
An electrode should be repositioned when it is how many inches from the torch?
1 1/2 - 2in ( 38-50mm)
How do you strike an arc with CAC-A?
By touching the electrode to the base metal momentarily
True or false? You want to avoid touching the electro to the base metal as it causes contamination
True
What do you want to ensure before starting to gouge?
air valve is opened all the way, air jets are positioned between the electrode and workplace, and the stick out is correct
True or false? Gouging can be done in all positions
True
Gouging in the vertical position is usually done in the uphill or downhill direction?
Downhill
What removes the molten metal from the groove?
The compressed air
How can Harden areas produced by CAC-A be removed?
By grinding
