(2024 Exam) UnderWater Cutting and Welding

Question 1

What is the COA when a pop is heard while cutting or welding?

Answer 1

Stop all cutting and welding work and investigate the cause.

Question 2

Can you substitute compressed air for O2 in U/W cutting?

Answer 2

No, due to the dangers of contaminating O2 regulators and hoses with oil residue.

Question 3

what is the preferred current used for U/W cutting and welding?

Answer 3

DC.

A/C power shall NOT be used.

Question 4

What is the O2 purity standards for cutting?

Answer 4

O2 cutting should be 99.5% or greater.

Question 5

To ensure sufficient O2 flow, a high flow regulator capable of delivering ___CFM is necessary?

Answer 5

70 CFM

Question 6

What is the over bottom pressure for cutting?

Answer 6

90PSI. Computed for depths up to 300ft.

Question 7

Only ___ type clamps should be used as grounding clamps?

Answer 7

C type

Question 8

What is the formula for calculating Regulator pressure setting for O2?

Answer 8

H/10 + (0.445 * D) +90
(Where H is hose length.)

Question 9

Steel plate 1/4” thick or greater should be cut using the ____ ______?

Answer 9

Drag Technique

Question 10

The hand should never be any closer than ___” from the electrode tip?

Answer 10

4”

Question 11

While holding the electrode _______, how long should the Diver visually check O2 flow from the electrode?

Answer 11

Horizontal, 20 seconds.

Question 12

When the electrode has been consumed to within ___” of the torch, stop the cut and call for switch off.

Answer 12

3”

Question 13

Exothermic Electrodes
It is not safe to operate the torch without the _______ ________ installed?

Answer 13

Flashback arrestor.

Question 14

3/8” electrodes is ___” or ___” long. The ultrathermic electrode will melt almost any material with it’s _______ degree F plus, tip heat.

Answer 14

18” or 36” , 10,000 degree.

Question 15

The Sea-Jet electrode will operate on a wide range of amp settings up to ____amps? With optimum cutting results with ____-____ amps.

Answer 15

400amps, 200-300amps.

Question 16

Gauntlet-type gloves worn over a pair of _____-____ gloves afford the best protection. In cold water, ______ gloves, worn over _______ gloves are equally effective?

Answer 16

Playtex-type, Diving, Surgical.

Question 17

Hold the electrode at a ___ to ___ degree angle?

Answer 17

45 to 90 degree. depending on material thickness.

Question 18

A ___” minimum oxygen emission should be maintained at the electrode tip?

Answer 18

6”

Question 19

Burning the electrode shorther than ___” can damage the torch interior?

Answer 19

3”

Question 20

For Kerie Cable, set the oxygen pressure to about ____psi and turn the Hoke valve to the ON position?

Answer 20

200psi.

Question 21

What are the disadvantages of Kerie Cable?

Answer 21

1) It requires more O2
2) It will not cut concrete, rock, or non-ferrous metals.

Question 22

In an emergency situation, what position do you turn the HOKE valve to instantly stop the cable from burning?

Answer 22

Turn to Vent.

Question 23

It is important that ignition NOT occur during what situation, that would cause the flame to burn sideways along the length of the cable?

Answer 23

When O2 pressure is too low.

Question 24

How far from the flame should you keep your hand when cutting with Kerie Cable?

Answer 24

6”

Question 25

What is the Root of a weld?

Answer 25

The point at which the bottom of the weld intersects the base metal surface, as seen in cross section. (i.e. the deepest part of the weld.)

Question 26

What is the FACE of a weld?

Answer 26

The exposed surface on the side from which the weld was made. (i.e. the part you can see once done welding)

Question 27

What is the toe of a weld?

Answer 27

The junction between the face of the weld and the base metal. (i.e. the sides of the face where it joins the base metal.)

Question 28

What is the LEG of a weld?

Answer 28

The part of the weld between the TOE and the ROOT. (i.e. the angled depth of the weld.)

Question 29

What three dive rigs are authorized for U/W C&W?

Answer 29

KM-37, KM-97 & MK-20.

Question 30

What is the minimum recommend safety switches ratings?

Answer 30

400amps/250 volts minimum.

Question 31

What is the recommended amperage for C&W?

Answer 31

400 amps or greater with a minimum of 60 percent duty cycle.

Question 32

When testing polarity, bubbles seen coming from the electrode tip indicates?

Answer 32

Straight polarity. DC electrode Negative (-)

Question 33

When testing polarity, bubbles seen coming from the plate indicates? What should be done?

Answer 33

Reversed polarity, change the lead connections to the opposite terminals.

Question 34

Once the correct polarity is determined, the ground clamp should then be bolted to the ________ lead and the electro holder attached to the ______ lead?

Answer 34

Ground (+)
Holder (-)

Question 35

The use of an approved, _______-_______ safety switch in the welding and cutting circuit is mandatory?

Answer 35

Positive-acting

Question 36

What should be done to cables to minimize contact resistance?

Answer 36

Wrap in rubber tape, apply a layer of scotch cote, then a final wrap w/ electrical tape.

Question 37

Disadvantage of using steel tubular electrodes?

Answer 37

*Burn time is short (usually less than one min).
* Produces narrow gap that may be difficult to see.
* Requires a welding machine
* Required higher amps deteriorates the holder more rapidly