120103k Submerged Arc Welding (SAW)

Question 1

Question: Describe and explain the principles of operation of SAW.

Answer 1

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.

Question 2

Question: What position(s) can SAW be used in?
Options:
a) flat position only
b) flat and horizontal positions
c) flat and vertical positions
d) flat, horizontal and vertical positions

Answer 2

Answer: b) flat and horizontal positions
Explanation: Submerged Arc Welding (SAW) is most effectively and commonly used in flat and horizontal positions. This is due to the nature of the welding process, which involves a granular flux that is easier to control in these positions. While it’s technically possible to use SAW in other positions, the efficiency and quality of welding are optimized in flat and horizontal positions.

Question 3

Question: Name four types of materials that SAW can be used on.

Answer 3

Answer: a) carbon, b) alloy steels, c) stainless steels, d) nickel alloys
Explanation: SAW is versatile and can be used on various materials, including carbon, alloy steels, stainless steels, and nickel alloys.

Question 4

Question: List the seven basic equipment components required for a SAW set-up and briefly explain their functions.

Answer 4

a) The welding power source provides welding current.
b) The welding head assembly includes the wire feeder, torch assembly and travel carriage (machine and automatic operation).
c) The fixtures and positioners position the work piece for welding.
d) Spooled filler wire provides filler metal for the weld.
e) The flux provides shielding, shapes the bead and allows alloys to be added.
f) The flux feed and recovery equipment conveys flux to the weld zone and collects unused flux.
g) The work lead connection completes the welding current circuit to the work
piece.
Explanation: These components collectively enable the SAW process, from providing power and feeding materials to supporting and shielding the weld zone.

Question 5

Question: What are two advantages of using a screw-type work clamp with SAW?

Answer 5

Answer: a) It provides a strong and positive contact to the work, b) It minimizes heat build-up.
Explanation: Screw-type work clamps are effective in ensuring strong contact and reducing heat, crucial for SAW efficiency and safety.

Question 6

What type(s) of output slope do SAW power sources use?

a) CC
b) CV
c) Variable potential
d) CC and CV

Answer 6

Answer: d) CC and CV
Explanation: SAW power sources use both Constant Current (CC) and Constant Voltage (CV) output slopes. This dual capability allows for flexibility in adjusting to different welding conditions and requirements.

Question 7

What duty cycle rating is recommended for most SAW power sources?

a) 40%
b) 60%
c) 80%
d) 100%

Answer 7

Answer: d) 100%
Explanation: A 100% duty cycle rating is recommended for most SAW power sources, indicating they can operate continuously at a specified output without overheating.

Question 8

SAW may be used in the semi-automatic or automatic operation modes.

a) true
b) false

Answer 8

Answer: a) true
Explanation: SAW is versatile and can be used in both semi-automatic and automatic operation modes, providing flexibility for different welding applications.

Question 9

What is the advantage of using an AC power source for SAW?

a) It uses less power than DC equipment.
b) The arc is more stable than DC current.
c) It minimizes arc blow with multiple wire set-ups.
d) AC power sources have higher duty cycle ratings than DC machines.

Answer 9

Answer: c) It minimizes arc blow with multiple wire set-ups.
Explanation: AC power sources are preferred for SAW, especially with multiple wire setups, as they help minimize arc blow, which can be a significant issue in such configurations.

Question 10

What will usually result if the drive roll pressure is set too low?

a) The wire electrode will slip and feed erratically.
b) The wire can pile up inside the wire feed unit.
c) The wire will stub the workpiece.
d) The wire will freeze to the workpiece.

Answer 10

Answer: a) The wire electrode will slip and feed erratically.
Explanation: Insufficient drive roll pressure can cause the wire electrode to slip, leading to erratic feeding and potential issues with the welding process.

Question 11

How will the arc react if the flux layer is too shallow?

a) The weld bead will appear rough and ropy.
b) The weld bead will have worm holes in it.
c) The weld will be flashing and will likely result in porosity.
d) The filler wire will always freeze to the workpiece.

Answer 11

Answer: c) The weld will be flashing and will likely result in porosity.
Explanation: A shallow flux layer can cause the arc to flash, which often results in porosity in the weld, compromising its quality.

Question 12

Which is helix?

a) straightening of the wire before it enters the drive roll assembly
b) the diameter of a single loop of wire
c) the turning action of the wire as it unrolls
d) the space between two unrestrained loops of wire

Answer 12

Answer: d) the space between two unrestrained loops of wire
Explanation: Helix refers to the space between two unrestrained loops of wire. It’s an important aspect in wire feeding and handling in welding processes.

Question 13

What type(s) of drive rolls are normally used with SAW?

a) angled
b) U-groove
c) flat or smooth-faced
d) knurled or V-groove

Answer 13

Answer: d) knurled or V-groove
Explanation: Knurled or V-groove drive rolls are typically used with SAW. They provide the necessary grip and control for smooth wire feeding, which is crucial for consistent welding quality.

Question 14

Question 14: What type of wire feed set-up is used with CV power sources?

a) constant speed
b) voltage-sensing
c) amperage-sensing
d) arc force-controlled

Answer 14

Answer: a) constant speed
Explanation: For CV (Constant Voltage) power sources in SAW, a constant speed wire feed set-up is typically used. This setup ensures that the wire feeding rate is maintained consistently, which is crucial for stable arc characteristics and uniform weld quality in the SAW process.

Question 15

List the six main SAW operating variables and their effects.

Answer 15

Answer: a) Amperage controls penetration and rate of deposit, b) Voltage affects arc length, c) Travel speed affects the penetration and weld bead profile, d) Electrode diameter has a direct effect on the weld bead shape, depth of penetration, and weld metal deposition rates, e) Electrode extension affects rate of metal deposition and flux layer depth, f) Width and depth of flux layer influence arc action, bead appearance, and weld metal soundness.

Explanation: These variables are essential in SAW for controlling the weld quality and characteristics. Each variable has a specific impact on the welding process, affecting factors such as penetration, deposition rate, bead shape, and overall weld quality.

Question 16

To increase arc length when you are welding with SAW, you would:

a) use a longer contact tip
b) increase wire feed speed
c) increase arc voltage
d) use a shorter contact tip

Answer 16

Answer: c) increase arc voltage
Explanation: Increasing the arc voltage in SAW results in a longer arc length. This is a critical adjustment for controlling the welding process and ensuring the desired weld characteristics.

Question 17

When using SAW, an increase in the arc voltage produces a:

a) wider arc stream and shallower penetration
b) wider arc stream and deeper penetration
c) narrower arc stream and shallower penetration
d) narrower arc stream and deeper penetration

Answer 17

Answer: a) wider arc stream and shallower penetration
Explanation: Higher arc voltage in SAW typically leads to a wider arc stream and shallower penetration, affecting the weld bead shape and depth.

Question 18

When is DCEN used with SAW?

a) when deeper penetration is required
b) when welding on non-ferrous materials
c) when shallower penetration is required
d) for applications requiring more than 1500 amperes

Answer 18

Answer: c) when shallower penetration is required
Explanation: DCEN (Direct Current Electrode Negative) is chosen in SAW when shallower penetration of the weld is desired. This polarity influences the distribution of heat and the depth of the weld.

Question 19

Why are wire cast and helix requirements placed in CSA and AWS specifications for SAW filler metals?

Answer 19

Answer: They ensure that the electrode wire will feed smoothly to the weld zone.
Explanation: The specifications for wire cast and helix in CSA and AWS standards are crucial for ensuring smooth and consistent feeding of the wire into the weld zone, which is essential for maintaining the quality of the welding process.

Question 20

Question: What diameters are SAW electrode wires available in?

a) 1.6 mm to 6.4 mm (1/16” to 1/4”)
b) 2.5 mm to 9.6 mm (3/32” to 3/8”)
c) 3.2 mm to 12.7 mm (1/8” to 1/2”)
d) 4.0 mm to 19 mm (5/32” to 3/4”)

Answer 20

Correct Answer: a) 1.6 mm to 6.4 mm (1/16” to 1/4”)
Explanation: SAW electrode wires are available in a range of diameters from 1.6 mm to 6.4 mm, or equivalently from 1/16 inch to 1/4 inch. This range of sizes allows for flexibility in welding applications, ensuring that welders can select the most suitable wire diameter for the specific welding task at hand.

Question 21

What is the main difference between the CSA and AWS classification systems for SAW electrode wires?

a) CSA uses the imperial system to measure tensile strength values
b) AWS uses the metric system to measure tensile strength values
c) CSA uses the metric system to measure tensile strength values
d) AWS uses yield strength values, while the CSA uses tensile strength values in their classification system

Answer 21

Answer: c) CSA uses the metric system to measure tensile strength values
Explanation: The primary difference between CSA and AWS classification systems lies in the measurement units used for tensile strength values, with CSA using the metric system.

Question 22

Interpret the AWS classification for the F7AZ-EL12K flux/wire designation.

a) F
b) 7
c) A
d) Z
e) E
f) L
g) 12
h) K

Answer 22

Answer:
a) F: designates a flux
b) 7: minimum tensile strength x 10,000 psi (70,000 psi)
c) A: as-welded condition
d) Z: no impact properties are specified
e) E: electrode
f) L: low manganese content
g) 12: nominal carbon content (0.12%)
h) K: made from fully killed steel
Explanation: This classification system details specific aspects of the flux/wire designation, including tensile strength, welding conditions, chemical composition, and the type of steel used in the electrode.

Question 23

Interpret the CSA classification for the F49AZ-EM14K flux/wire designation.

a) F
b) 49
c) A
d) Z
e) E
f) M
g) 14
h) K

Answer 23

Answer:
a) F: designates a flux
b) 49: minimum tensile strength in megapascals x 10 (490 MPa)
c) A: as-welded condition
d) Z: no impact properties are specified
e) E: electrode
f) M: medium manganese content
g) 14: nominal carbon content (0.14%)
h) K: made from fully killed steel
Explanation: This CSA classification outlines the key attributes of the flux/wire, including the material properties and the welding conditions under which it is tested.

Question 24

Which type of flux can be re-used?

a) bonded
b) agglomerated
c) fused
d) rutile-based

Answer 24

Answer: c) fused
Explanation: Fused flux is a type of flux used in SAW that can be recycled and reused in the welding process, which is not typically possible with other flux types like bonded, agglomerated, or rutile-based fluxes.

Question 25

Which type of SAW flux is generally used for the addition of alloying elements?

a) active flux
b) fused flux
c) recycled flux
d) neutral flux

Answer 25

Answer: a) active flux
Explanation: Active fluxes are typically used in SAW for adding alloying elements to the weld. These fluxes interact chemically with the weld pool, influencing the final composition of the weld metal.

Question 26

What should be done with SAW fluxes after they have become exposed to moisture?

a) They should be discarded.
b) They should be dried or re-baked according to manufacturer specifications.
c) They should only be used for non-critical welds.
d) They should be used at 35 arc volts or higher to allow moisture and gases to escape the weld before solidification.

Answer 26

Answer: b) They should be dried or re-baked according to manufacturer specifications.
Explanation: Moisture in SAW fluxes can lead to welding defects. Therefore, if the fluxes are exposed to moisture, they should be dried or re-baked as per the manufacturer’s guidelines to remove any absorbed moisture before use.

Question 27

Name four (4) process-related causes of an unstable arc.

Answer 27

Answers: 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

Explanation: These factors can disrupt the stability of the arc in SAW, leading to poor weld quality. Cleanliness of the joint, appropriate electrical stickout, adequate flux coverage, proper wire feed, and correct voltage/amperage settings are crucial for a stable arc.

Question 28

Name three (3) things you should check for when the wire feed motor operates, but the wire fails to feed.

Answer 28

Answers: 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

Explanation: These issues can prevent proper wire feeding in SAW, despite the motor operating. Ensuring proper drive roll pressure, correct wire drive rolls, and unclogged wire paths is essential for consistent wire feeding.

Question 29

Are higher deposition rates obtainable with the SAW process?

a) yes
b) no

Answer 29

Answer: a) yes

Explanation: SAW is known for its high deposition rates, making it efficient for large-scale welding operations where rapid material deposition is advantageous.

Question 30

Is SAW easily done in all positions?

a) yes
b) no

Answer 30

Answer: b) no

Explanation: SAW is typically limited to flat and horizontal positions due to the nature of the process and the requirement for granular flux. Welding in other positions can be more challenging and less efficient.