Chapter 9 SMAW Flashcards
What is the temperature of the arc in SMAW?
Can be over 9000F (500C)
What is polarity?
The direction in which the electrons flow
Power sources produce which two types of currents?
AC (alternating current) and DC (direct current)
What is DCEN (direct current electrode negative)?
The arc welding method in which direct current flows from the electrode which is negative to the work piece.
What is DCEP (direct current electrode positive)
The arc welding method in which direct current flows from the work piece which is negative to the electrode.
What is a benefit of DCEP?
Produces deeper penetration than DCEN
When would DCEN be useful?
When using thin metals because it doesn’t penetrate deeply.
What is a benefit of DCEN
It can deposit a filler metal at a faster rate than DCEP
Alternating current (AC) operates at ______ cycles per second
60 cycles per second
A ______________ is a set of repeating events such as the flow and reversal of flow in an electric circuit.
cycle
Alternating current flows in one direction for _______ of a second, then reverses its direction and flows for ______ second to form one complete cycle.
1/120 sec and 1/120 sec for a total time of 1/60 sec
Define constant current (CC)
Term used for arc welding machines produce a nearly constant current even though the voltage may vary
Define constant voltage (CV)
Term used for arc welding machines that alter currents as needed to produce a nearly constant voltage
what is another term for droopers or droop curve machines?
CC welding machines
Which of the following welding machines does not produce AC and DC welding currents?
Transformer
Why are welding transformers sometimes called step down transformers?
Because the voltage is reduced
Define primary current
Alternating current supplied to the input side of a transformer
Define secondary current
The current coming out of a transformer
What is duty cycle?
It is a rating that indicates how long a welding machine can be used at its maximum output current without damaging it
A welding machine with a 60% duty cycle is based on a ______ minute time period
6-10 minute
_____________ is the voltage of the welding machine when it is on, but is not being used.
Open-circuit voltage (OCV)
The electric cable that connects the electrode holder to a welding machine is called the _______________
electrode lead
The ____________ is the electric cable that connects the base metal to the welding machine
workpiece lead
What determines the size of the lead?
- amount of the current being used
- distance/length of lead
What shouldn’t you do to attach a workpiece lead to a workpiece or worktable?
Weld the workpiece lead to the table
What filter lens number should be used when welding with a 3/16” SMAW electrode?
12
The vertical line in a bevel-groove and fillet weld symbols is always drawn at the _______ side of the weld symbol
left
