Mechanical Barriers
Cofferdams and caissons are used at the waters edge or in the splash zone and below the water surface. While the structure excludes the surrounding water from the work area, its upper section is open to the atmosphere. This technique is depth-limited by the physical size of the cofferdam. Typical applications include ship's hulls, dock and harbor facilities. 3-2.2 Mini-Habitats. Mini-habitat welding makes use of a small, easily portable, gas-filled enclosure....
Note
The thermic lance will operate on oxygen pressures from 80-120 psi. If the pipe burns faster than the filler rods, use more pressure. If the filler rods burn much faster than the pipe, use less pressure. Figure E-2. Thermic Lance Holder Assembly. Figure E-2. Thermic Lance Holder Assembly. A. THERMIC LANCE-INSERT TORCH INTO HOLDER (B) C. CONNECTING HOSE FOR REGULATOR ASSEMBLY (E) D. COUPLING TO ATTACH (C) TO (E) - UNIT (D) CONSISTS OF A COUPLING AND A HOSE CLAMP E. TWO STAGE REGULATOR CAPABLE OF...
Underwater Shielded Metal Arc Welding Techniques
There are two basic techniques used today in shielded metal arc wet welding the self-consuming technique and the manipulative or weave technique. Paragraph 3-12.3.3 describes the advantages of the self-consuming technique for the less experienced underwater welder. With the self-consuming technique, the electrode is dragged across the work and a significant amount of pressure must be applied by the diver. With the manipulative technique, the arc is held as it would be when welding on the...
Military Specification Number
Electrodes, oxy-arc cutting Ultrathermic (BROCO) 3 8-inch 1 4-inch Electrodes, SMA cutting and welding E 6013 E 7014 E 7018 E 308 E 309 E 310 E 312 ENiCrFe-2 ENiCrFe-3 ENiCrMo-3 Electrodes, SMA Wet Welding Andersen Easy Weld BROCO SofTouch BROCO SofTouch 3493 3493 3493 3493 3493 3493 3493 3493 N A AWSAS.1-78E7014 N A N A N A N A N A N A N A N A S0300-BB-MAN-010 Table 4-4. Parts Information Kerie Cable (SEELER) 6 mm 50-ft roll 9 mm 50-ft roll 12 mm 100-ft roll 1 4 x 1 4 British Standard Pipe...
List Of Illustrations
2-1 Underwater Oxygen-Arc Cutting 2-2 Underwater Oxygen-Arc Electrode 2-3 Drag Techniques for Cutting Steel with Steel-Tubular 2-4 Technique for Cutting Steel Less Than 1 4 Inch with Steel-Tubular Electrodes 2-16 2-5 Technique for Piercing Holes in Steel Plate using the Oxy-Arc Process with Steel Tubular 2-6a Underwater Oxygen-Arc Cutting Torch Breakdown 2-6b Underwater Oxygen-Arc Cutting Torch Breakdown 2-6c Underwater Oxygen-Arc Cutting Torch Breakdown 2-7 Technique for Cutting Steel Using...
Welding Accessories
In addition to the basic equipment, the following accessories are necessary for underwater shielded metal arc welding. a. A supplementary welding shield attached to the diving helmet fitted with No. 4, 6, 8 or 10 or other appropriate welding lens. b. A suitable grounding clamp (C-clamp) to which the ground lead is bolted or preferably brazed, thus making it easy for the diver to connect the lead to the work. c. A weighted wire brush for cleaning the base metal and removing slag. d. A chipping...
D10 Fire And Explosion Prevention
The major causes of fire and explosion are listed as follows combustibles reached by the arc, misuse of compressed gases and cylinders and It is necessary for the diving supervisor be aware of topside work being conducted in the vicinity of the diving station. Do not allow welding or cutting in an area where there are combustibles. Sparks and slag can fly up to 35 feet. Keep equipment clean and operable, free of oil and grease and free of metallic particles (in electrical...
D9 Safety Switch
A positive-acting, unfuzable current interrupt switch, rated at 400 amperes must be in the welding circuit. This switch protects the diver by breaking the electric circuit, thereby stopping the current supply to the electrode holder. A typical double-pole safety switch setup is shown in Figure 4-8. The safety switch, more often referred to as a knife switch, is the most important safety item included in the underwater cutting or welding equipment inventory. The diver is fully isolated from...
Exothermic Electrodes
Underwater Oxygen-Arc Cutting Electrodes Figure 2-1. Underwater Oxygen-Arc Cutting Electrodes Figure 2-2. Underwater Oxygen-Arc Electrode Designs. Figure 2-2. Underwater Oxygen-Arc Electrode Designs. c. It serves as an electrical insulator, even in wet conditions, thereby assisting in safeguarding the diver in the event of accidental body contact while cutting. d. It prevents arcing from the side of the electrode when working in confined quarters. 2-2.2.1 Advantages of the...
Underwater Cutting
Serious injury or death may result when adequate precautions are not followed during underwater cutting or welding operations. Supervisors shall ensure that all personnel become thoroughly familiar with the safety precautions covered in Appendix D. Under no circumstances shall compressed air be substituted for oxygen in underwater cutting operations due to the danger of contaminating oxygen regulators and hoses with oil residue (hydrocarbons). The position of the ground in relation to the diver...
Underwater Oxygen Arc Cutting Torches
Underwater oxygen arc cutting torches are designed for gripping the cutting electrodes and for delivering power to the electrode and oxygen to the electrode bore. Safety is a primary consideration in their design and construction. All current-carrying parts of the torches must be fully insulated to afford full protection to the diver from electric shock and to protect the torch from rapid corrosion due to electrolysis. The torches also should be lightweight, simple in construction, easy to...
Procedure For Repairing Small Cracks
Preparation is the key to stopping crack propagation. Attempts to stop a crack by filling in with weld metal most often result in failure as the crack is very likely to open up again through the weld. Therefore, small patches, preferably circular ones, are recommended. These patches can be readily attached to the hull of a ship by fillet welding because the groove of the fillet provides a guide for depositing the electrode. The following procedures are recommended a. Locate the ends of the...
E7 Friction Stud Welder
Historically, friction welding has been restricted to large heavy equipment permanently installed in workshops and stud attachment has involved an electrical process with a power source capable of delivering several hundred amps from a three-phase power supply. The SEASTUD portable friction welder, Figure E-8, is a lightweight, hand-held air-tool which will attach various size studs to metals and other materials. E-7.1 Principle of Operation. The friction welding process produces a weld by...
Materials Used In Underwater Shielded Metal Arc Welding
Equipment used for shielded metal arc welding is discussed in Chapter 4. Consumable materials required for shielded metal arc welding consist of commercially produced waterproofed wet welding electrodes. Table 3-2 lists the preferred electrodes identified during wet welding screening and certification tests conducted by the Navy. 3-6.1 Underwater Shielded Metal Arc Welding Electrodes. Commercial manufacturers have made significant progress in the development of waterproofing systems for wet...
Equipment Used For Underwater Arc Cutting And Welding
4-2.1 Oxygen-Arc and Shielded Metal Arc Equipment. Underwater oxygen arc cutting and shielded metal arc cutting and welding are performed with basically the same equipment. A typical arrangement of this equipment is illustrated in Figure 4-1 additional accessories not shown include scrapers and wire brushes which are used for both underwater cutting and welding operations. The equipment is also listed in Table 4-1. 4-2.2 Diving Equipment. The standard Navy MK 1, MK 12 or Superlite-17 helmets...
Underwater Welding
Serious injury or death may result when adequate precautions are not followed during underwater cutting or welding operations. Supervisors shall ensure that all personnel become thoroughly familiar with all of the safety precautions covered in Appendix D. The position of the ground in relation to the diver must be such that at no time does the diver or his equipment get between the ground and the electrode. The diver must avoid becoming part of the electrical circuit. AC power shall not be used...
Conditions Adverse To Underwater Welding
Before welding operations are started, the job should be inspected to determine whether or not the welding can be performed effectively at the work site. Satisfactory underwater welds are more difficult than welds laid down topside. The following factors make underwater welding difficult b. Where a steady platform cannot be provided from which to weld. (Working near the surface in rough water makes it difficult to provide a stable platform. When working from a stage, it is preferable to attach...
Exothermic Cutting Technique Cast Iron Stainless Steel and Non Ferrous Metals
Cast iron, stainless steel and non-ferrous metals do not oxidize therefore, underwater cutting becomes a melting process. The exothermic process develops tip-temperatures in excess of 10,000 oF, which is sufficient to melt these materials with ease. The following technique is recommended a. Keep the tip firmly buried in the puddle. Using a sawing motion, manipulate the electrode in and out of the cut. b. To cut thick, non-ferrous metals, create a puddle and keep the electrode tip slightly below...
Table E4 Recommended Cutting Tip Sizes
The spacer sleeve, shown in Figure E-4 clamps over the cutting tips and is used to keep the cutting tips at the proper distance from the work, which should be a minimum of 3 16 inch and a maximum of 1 4 inch for the cutting tip. This sleeve should also be perforated to allow water to circulate around the cutting tip. After the tip and spacer sleeve are seated, the flame should be lit and adjusted. It is necessary to set the recommended regulator pressures with the flame burning and the cutting...
Shielded Metal Arc Cutting
Underwater shielded metal-arc cutting is a simple process. It employs a stick-type electrode but can be accomplished with almost any waterproofed, mild steel electrode. Shielded metal arc has the following advantages over oxygen-arc cutting processes a. It can cut corrosion and oxidation resistant steels and non-ferrous metals of all thicknesses. b. It can be used when no oxygen is available. 2-5.1 Principles of Operation. Shielded metal-arc cutting is a process in which the metal is cut by the...
Safety In Underwater Cutting And Welding
This appendix is intended to cover safety precautions to be followed while preparing for and conducting underwater cutting or welding operations. All personnel should read and comprehend the safety precautions listed in this section and the safety summary contained in the front section of this manual. Deviation from established standards are of course potentially dangerous however, the most serious aspect of disregarding safety rules may not be the initial deviation, but the tendency to treat...
Advantages and Disadvantages of the Kerie Cable The advantages of the Kerie Cable are as follows
There is less training and skill required. b. It is applicable to all metal thicknesses. d. It has the ability to cut in hard-to-reach spots without frequent electrode changing. e. There is no electrical hazard after ignition. The electrical circuit is used only for igniting the thermic cable. f. It cuts on the surface as well as underwater. h. Only one gas oxygen is needed. The disadvantages of the Kerie Cable are as follows b. It will not cut concrete, rock, or non-ferrous metals. Learning...
Warning
Hydrocarbons ignite almost spontaneously in the presence of oxygen. Never allow oxygen-carrying components to come in contact with oil or grease. 2-2.13 Post-dive Maintenance. After each use, rinse the torch in fresh water and dry it. Disassemble and inspect the flashback arrestor for corrosion damage due to electrolysis or clogging. Frequent clogging or screen burn-out indicates either insufficient oxygen pressure or burning the electrode shorter than the 3-inch minimum. Replace any damaged...
