U/W Cutting and Welding

Question 1

What. are the 2. methods of U/W cutting being used?

Answer 1

Oxygen-Arc

Shielded Metal-Arc

Question 2

Can the diver ever be in-between the ground and the electrode?

Answer 2

NO- diver must avoid becoming a-part of the electrical circuit

Question 3

What are the 2 different types of electrodes used for Oxygen-Arc cutting?

Answer 3

• Steel-Tubular (manufactured by Arc-Air)

- Exothermic (types like Arc-Air’s Sea Set & Broco’s Ultrathermic)

Question 4

What current is used for U/W Cutting?

Answer 4

DC only

Question 5

What is the polarity set to for U/W Cutting?

Why is this method. prefered?

Answer 5

Straight. Polarity (electrode negative)

Preferred method because it cuts plain & Low Carbon steel easily

Question 6

Can compressed air be substituted for O2 in U/W Cutting?

Answer 6

NO- Hydrocarbons can. contaminate the O2 regulator. and hoses with oil residue

Question 7

What are the cutting amperage for both Arc-Air Steel Tubular electrodes?
Sea-Cut?
Tuff-Cote?

Answer 7

300-400 AMPS

Question 8

What are the characteristics of. a steel tubular electrode?

Answer 8

• Steel tube with a water proofed flux coating
• 14 inches long
• 5/16 inch outer. diameter
• Bore diameter slightly less than 1/8. inch or 0.112” Bore
• 1 1/2” - 1 3/4” steel exposed

Question 9

What purpose does flux coating serve for the steel tubular electrode?

Answer 9

• Promotes easy maintenance & storing of the rod
• It liberates gasses, thus forming a protective bubble. around the arc
• Serves as an electrical insulator protecting the diver in wet conditions
• prevents arcing from the side of the electrode when working in confined quarters

Question 10

What are the advantages of steel-tubular electrodes?

Answer 10

• Simple cutting. technique
• Cut. metals 2 inch thick
• Neat, trim, narrow cuts are produced
• Within 400amp welder capacity
• There is less electrode waste because electrode must be in constant contact with metal being cut to sustain an arc

Question 11

What are the disadvantages if the steel-tubular electrode?

Answer 11

• Burn time is short (approx 1 min per electrode)
• Narrow gap produced is difficult t o locate in poor vis
• Welding machine is required
• Higher amperage requirement deteriorates electrode holder more rapidly then exothermic process