(2024 Exam) UnderWater Cutting and Welding Flashcards
Ch 3, 4, 5.
What is the COA when a pop is heard while cutting or welding?
Stop all cutting and welding work and investigate the cause.
Can you substitute compressed air for O2 in U/W cutting?
No, due to the dangers of contaminating O2 regulators and hoses with oil residue.
what is the preferred current used for U/W cutting and welding?
DC.
A/C power shall NOT be used.
What is the O2 purity standards for cutting?
O2 cutting should be 99.5% or greater.
To ensure sufficient O2 flow, a high flow regulator capable of delivering ___CFM is necessary?
70 CFM
What is the over bottom pressure for cutting?
90PSI. Computed for depths up to 300ft.
Only ___ type clamps should be used as grounding clamps?
C type
What is the formula for calculating Regulator pressure setting for O2?
H/10 + (0.445 * D) +90
(Where H is hose length.)
Steel plate 1/4” thick or greater should be cut using the ____ ______?
Drag Technique
The hand should never be any closer than ___” from the electrode tip?
4”
While holding the electrode _______, how long should the Diver visually check O2 flow from the electrode?
Horizontal, 20 seconds.
When the electrode has been consumed to within ___” of the torch, stop the cut and call for switch off.
3”
Exothermic Electrodes
It is not safe to operate the torch without the _______ ________ installed?
Flashback arrestor.
3/8” electrodes is ___” or ___” long. The ultrathermic electrode will melt almost any material with it’s _______ degree F plus, tip heat.
18” or 36” , 10,000 degree.
The Sea-Jet electrode will operate on a wide range of amp settings up to ____amps? With optimum cutting results with ____-____ amps.
400amps, 200-300amps.
Gauntlet-type gloves worn over a pair of _____-____ gloves afford the best protection. In cold water, ______ gloves, worn over _______ gloves are equally effective?
Playtex-type, Diving, Surgical.
Hold the electrode at a ___ to ___ degree angle?
45 to 90 degree. depending on material thickness.
A ___” minimum oxygen emission should be maintained at the electrode tip?
6”
Burning the electrode shorther than ___” can damage the torch interior?
3”
For Kerie Cable, set the oxygen pressure to about ____psi and turn the Hoke valve to the ON position?
200psi.
What are the disadvantages of Kerie Cable?
1) It requires more O2
2) It will not cut concrete, rock, or non-ferrous metals.
In an emergency situation, what position do you turn the HOKE valve to instantly stop the cable from burning?
Turn to Vent.
It is important that ignition NOT occur during what situation, that would cause the flame to burn sideways along the length of the cable?
When O2 pressure is too low.
How far from the flame should you keep your hand when cutting with Kerie Cable?
6”
What is the Root of a weld?
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.)
What is the FACE of a weld?
The exposed surface on the side from which the weld was made. (i.e. the part you can see once done welding)
What is the toe of a weld?
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.)
What is the LEG of a weld?
The part of the weld between the TOE and the ROOT. (i.e. the angled depth of the weld.)
What three dive rigs are authorized for U/W C&W?
KM-37, KM-97 & MK-20.
What is the minimum recommend safety switches ratings?
400amps/250 volts minimum.
What is the recommended amperage for C&W?
400 amps or greater with a minimum of 60 percent duty cycle.
When testing polarity, bubbles seen coming from the electrode tip indicates?
Straight polarity. DC electrode Negative (-)
When testing polarity, bubbles seen coming from the plate indicates? What should be done?
Reversed polarity, change the lead connections to the opposite terminals.
Once the correct polarity is determined, the ground clamp should then be bolted to the ________ lead and the electro holder attached to the ______ lead?
Ground (+)
Holder (-)
The use of an approved, _______-_______ safety switch in the welding and cutting circuit is mandatory?
Positive-acting
What should be done to cables to minimize contact resistance?
Wrap in rubber tape, apply a layer of scotch cote, then a final wrap w/ electrical tape.
Disadvantage of using steel tubular electrodes?
*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
