Wire Feed Welding Equipment Power Sources Flashcards
What colour should your protective clothing be when welding with GMAW and why?
clothing should be dark to reduce reflected light radiation
Is it advisable to weld with any arc welding process under wet weather conditions? explain.
when you are exposed to wet weather conditions or standing on wet surfaces, protect yourself from electrical shock hazards by wearing rubber boots with dry socks and rubber gloves
The use of shielding gases when using wire feed processes increases the need for good:
a) lighting
b) ventilation
c) heat shielding
d) eye protection
b) ventilation
Name 2 toxic gases that can be created from the ultraviolet light produced from welding.
ozone
phosgene gas
How can air quality be affected when welding with a process that uses a shielding gas?
shielding gases in sufficient qualities displace enough air to render the work area oxygen deficient. Dizziness or euphoria is usually the first sign of oxygen deficiency. Precautions must always be taken to ensure adequate breathing air is supplied.
High Ultraviolet radiation emissions form an open arc can cause atmospheric oxygen in the vicinity of the arc to convert to:
a) ozone
b) carbon monoxide
c) carbon dioxide
d) argon
a)ozone
A potential source of poisonous chemical fumes when welding is:
a) inert shielding gases
b) chlorinated degreasing solvents
c) carbon dioxide extinguishers
d) anti-spatter novel sprays
b) chlorinated degreasing solvents
Define and describe the GMAW process in detail
GMAW is an arc welding process that uses an arc between a continuous filler metal electrode and the weld pool. The process uses shielding gas from an externally supplied source.
The gas metal arc welding process is also known as:
a) MIG welding
b) Flux cored arc welding
c) self-shielding process
d) shielded metal arc welding
a) MIG welding
GMAW is recommended for use on which of the following metals: a) stainless steel b) aluminum c) copper alloys d_ carbon and low alloy steels e) all of the above
e) all of the above
Describe the operating principles of FCAW.
FCAW uses an arc established between a continuously fed consumable electrode and the work piece. Appropriate settings made by the operator maintain a constant burn-off rate of the wire electrode. Depending on the power source and wire drive system used, the arc length is maintained automatically . Shielding gas can be externally applied and/or obtained from a flux contained within the hollow electrode core. (depending on the type of flux cored wire used).
Self-shielded FCAW uses shielding gas generated from:
a) the base metal
b) an external source
c) the flux
d) a paste flu applied to the base metal before welding
c) the flux
What is the electrode extension range for self-shielded FCAW
For self-shielded electrodes, extensions range from 19m to 95mm (3.4” - 3 3/4”)
The MCAW process uses the same equipment as which process?
a) SMAW
b) GTAW
c) FCAW
d) OAW
c) FCAW
List the basic equipment components always required for the set-up of a wire feed outfit
a) power source
b) wire feeder
c) gun and cable assembly
d) spooled filler wire
e) shielding gas and
f) gas control equipment
How are wire feed guns rated?
a) by voltage-carrying capacity
b) by physical size
c) by current-carrying capacity
d) by shielding gas flow rate
c) by current-carrying capacity
The major factor in choosing between an air-cooled or a water-cooled gun is the required:
a) shielding gas
b) current/voltage
c) joint design
d) base metal alloy
b) current/voltage
Welding power sources designed only for wire feed welding can be used for shielded metal arc welding (SMAW).
True - or - False
False
GMAW may be used in the semi-automatic or automatic operation modes.
True - or - False
True
What type of welding power source is most often used for GMAW?
constant voltage
Constant voltage (CV) machines produce a:
a) drooping volt-amp curve
b) rising volt-amp curve
c) Relatively flat volt-amp curve
d) constantly changing volt-amp curve
c) Relatively flat volt-amp curve
The power source best suited for the short-circuit mode of metal transfer is a:
a) rising arc voltage power source
b) constant voltage power source
c) constant current power source
d) constant amperage power source
b) constant voltage power source
What type of volt-amp curve does a constant current machine produce
a) flat
b) variable
c) rising
d) drooping
d) drooping
A welding machine that produces an almost horizontal output slope is a:
a) constant current machine
b) constant voltage machine
c) rising arc voltage machine
d) high amperage potential welding machine
b) constant voltage machine
List 3 advantages and 3 disadvantages of GMAW.
Advantages:
lower skill requirements than SMAW
excellent for light gauge metals
good arc control when working with poor fit-ups
less heat input means less distortion than SMAW
high production rates
no slag to remove, little or no post weld clean-up
Disadvantages:
special equipment required resulting in higher initial cost
equipment requires more maintenance and down time
lack of fusion can be a problem
cannot be used outdoors or in draft locations
high radiant energy requires protetction for the welder and others in the area
wire feeder must be in close proximity to welding.
One of the main advantages of metal core wires is:
a) lower cost than flux core wires
b) no external shielding gas is required
c) designed for use on conventional CC power sources
d) high deposition rates
d) high deposition rates
List 3 advantages and 3 disadvantages of FCAW.
Advantages:
The deposition rate is up to 4 times greater than with SMAW
There is high operating factor, so it is easily mechanized
the visible arc is easy to use
the weld metal deposits are high quality.
Disadvantages:
The equipment is more expensive to purchase than that needed for SMAW
More smoke and fumes are generated, which require suitable exhaust removal equipment
the wire feeder must be in close proximity to the welding
equipment is more complex than for SMAW so it requires more maintenance.
The powder in a MCAW wire consists mostly of:
a) flux
b) metal
c) slag formers
d) arc stabilizers
b) metal
