Chapter 12 SMAW Flashcards
What is arc blow?
When the arc is deflected from its normal path by magnetic forces. It can present a challenge during arc welding.
Why is arc blow not a problem when AC is used?
Because the magnetic field is continually cancelled as the current changes direction therefore arc blow is not a problem when AC is used.
What is worn under the welding helmet to protect from reflected arc rays?
Eye protection
An electrode is generally held with one hand. It can be gripped like a ___________ or _____________
hammer or screwdriver
How do you strike an arc?
There are two methods:
1. welder scratches the electrode on the metal then withdraws it
2. use a straight up and down or pecking motion
Which of the following results in the least arc blow?
a. DCEN
b. DCEP
c. AC
d. DC
b. AC
The magnetic field around the electrode is deflected at ___________________ of a weld joint.
ends of the weld joint
If arc blow occurs, what step should you take?
Use the shortest arc possible to produce a good weld. A short arc permits the filler metal to enter the weld pool before being affected. A good short arc also permits the arc force to overcome the arc blow force.
A ______________ permits the arc force to overcome the arc blow force.
good short arc
The width of a stringer bead should be _______________ times the electrode diameter
two to three times
What is the travel angle?
It describes the position of the electrode as it is tilted along the weld axis
What is work angle?
It describes the position of the electrode as it tilts side to side about the weld axis.
What is backhand method
The welding end of the electrode points backward toward the weld bead that has been completed
What is forehand method?
The welding end the electrode points forward in the direction of travel
When restarting an arc, how far in front of the existing crater is the arc struck?
3/8” (10 mm)
Excessive current produces a weld that is wide, low, and has a great deal of ___________
spatter
Metal less than 1/4” thick is welded using a ______________________
square-groove butt joint
True or False: No edge preparation is required for metal 1/4” thick.
True
True or False: A bevel-, V-, J-, or U-groove joint is used on thicker metal.
True
What is a root pass?
The first and most important weld pass
What is the keyhole?
An enlarged root opening. Must be seen throughout the root pass to ensure penetration.
What is the whip and pause technique used on?
The whip and pause technique is used on a root pass of a butt weld. It involves moving the electrode towards a distance equal to about one electrode diameter and pausing very briefly.
_______________ occurs when the base metal at the weld toe area is melted but is not filled with filler metal.
Undercut
What is the work angle for a fillet weld on a T-joint?
45 degrees
