120103K Flashcards
Describe and explain the principles of operation of SAW
Submerged arc welding is an arc welding process in which metals are joined using an
electric arc established between a continuously fed bare metal consumable electrode or electrodes and the work. Shielding is provided by a granular, fusible flux material usually brought to the work area using a flux feed system.
What position(s) can SAW be used in?
flat and horizontal positions
Name four (4) types of materials that SAW can be used on.
1) carbon
2) alloy steels
3) stainless steels
4) nickel alloys
List the seven (7) basic equipment components required for a SAW set-up and briefly
explain their functions.
- The welding power source provides welding current.
- The welding head assembly includes the wire feeder, torch assembly and travel
carriage (machine and automatic operation). - The fixtures and positioners position the work piece for welding.
- Spooled filler wire provides filler metal for the weld.
- The flux provides shielding, shapes the bead and allows alloys to be added.
- The flux feed and recovery equipment conveys flux to the weld zone and collects
unused flux. - The work lead connection completes the welding current circuit to the work
piece
What are the advantages of using a screw-type work clamp with SAW?
- It provides a strong and positive contact to the work.
- It minimizes heat build-up.
What type(s) of output slope do SAW power sources use?
CC and CV
What duty cycle rating is recommended for most SAW power sources?
100%
SAW may be used in the _____________ or automatic operation modes
semi-automatic
What is the advantage of using an ac power source for SAW?
It minimizes arc blow with multiple wire set-ups.
What will usually result if the drive roll pressure is set too low?
The wire electrode will slip and feed erratically.
How will the arc react if the flux layer is too shallow?
The weld will be flashing and will likely result in porosity.
Helix is ______?
the space between two unrestrained loops of wire
What type(s) of drive rolls are normally used with SAW?
knurled or V-groove
What type of wire feed set-up is used with CV power sources?
constant speed
List the six (6) main SAW operating variables and their effects.
- Amperage controls penetration and rate of deposit.
- Voltage affects arc length.
- Travel speed affects the penetration and weld bead profile
- Electrode diameter has a direct effect on the weld bead shape, depth of
penetration and weld metal deposition rates. - Electrode extension affects rate of metal deposition and affects flux layer depth.
- Width and depth of flux layer has an influence on arc action, bead appearance and weld metal soundness.
To increase arc length when you are welding with SAW, you would:
increase arc voltage.
When using SAW, an increase in the arc voltage produces a ______
wider arc stream and shallower penetration.
When is DCEN used with SAW?
when shallower penetration is required
Why are wire cast and helix requirements placed in CSA and AWS specifications for
SAW filler metals?
They ensure that the electrode wire will feed smoothly to the weld zone
What diameters are SAW electrode wires available in?
1.6 mm to 6.4 mm (1/16” to 1/4”)
What is the main difference between the CSA and AWS classification systems for
SAW electrode wires?
CSA uses the metric system to measure tensile strength values.
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the F represent?
designates a flux
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the 7 represent?
minimum tensile strength x 10 000 psi (70 000 psi)
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the A represent?
as-welded condition
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the Z represent?
no impact properties are specified
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the E represent?
electrode
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the L represent?
low manganese content
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the 12 represent?
nominal carbon content (0.12%)
Using the AWS classification for the F7AZ-EL12K flux/wire designation, what does the K represent?
made from fully killed steel
Which type of flux can be re-used?
fused
Which type of SAW flux is generally used for the addition of alloying elements?
active flux
What should be done with SAW fluxes after they have become exposed to moisture?
They should be dried or re-baked according to manufacturer specifications.
Name four (4) process-related causes of an unstable arc?
Any four (4) of the following are correct.
a) joint dirty with scale or rust
b) incorrect electrical stickout
c) insufficient flux coverage
d) too much wire cast or helix causing poor wire feed
e) worn contact tube
f) incorrect voltage/amperage settings
Name three (3) things you should check for when the wire feed motor operates, but
the wire fails to feed.
Any three (3) of the following are correct.
a) insufficient drive roll pressure
b) incorrect wire drive rolls
c) excessive pressure on wire spool brake
d) drive rolls are dirty or clogged
e) blockage in the liner or torch
f) plugged wire guide tubes
Are higher deposition rates obtainable with the SAW
Yes
Is SAW easily done in all positions?
No
