Underwater Shielded Metal Arc Welding Electrodes. Commercial manufacturers have made significant progress in the development of waterproofing systems for wet welding electrodes. Details of these systems are proprietary to each manufacturer; however, the results of their cumulative efforts have produced a new generation of wet welding electrodes. Certain electrodes are manipulative types for use in all positions. With the correct
Read more →Underwater Welding Although underwater welding does not have as many applications in marine salvage operations as underwater cutting, welding is an extremely important and useful process. By substituting welding for mechanical methods of joining, the overall cost and time spent on the job can be reduced considerably. Historically, most underwater welding was done for the purpose of making temporary repairs
Read more →Exothermic electrode cutting technique. The 1/4-inch Exothermic electrode may be used to cut steel up to 1/2 inch in thickness. The 1/4 inch electrode leaves a narrow kerf and is preferable for fine cutting. When visibility is poor or when cutting heavier steel, the 3/8-inch electrode is more efficient. The following techniques are recommended: a. Insert the electrode into the
Read more →Steel-Tubular Electrode Cutting Technique (cast iron and non-ferrous metals). Cast iron and non-ferrous metals do not oxidize; therefore, underwater cutting essentially becomes a melting process. There is no chemical reaction of the oxygen and the base metal. Therefore, the only benefit realized by the oxygen is the mechanical effect of blowing the molten metal away. Since the melting process takes
Read more →Underwater Welding Arcs The welding arc does not behave underwater as it does on the surface and the activity of the gas bubble is particularly important to successful completion of the underwater weld. When the arc is struck, the combustion of the electrode and the detachment of water creates a gas bubble or envelope. As the pressure within the bubble
Read more →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: a. Diving apparel b. Where a steady platform cannot be provided from
Read more →Trouble Shooting Exothermic Electrodes. Oxy-arc, especially exothermic cutting relies on an unobstructed oxygen flow to be most effective. With inadequate oxygen flow, the rod will burn but not produce the desired cutting effect. Since the actual cutting result is derived from the volume of oxygen reaching the target, any restriction in oxygen flow will decrease efficiency. Symptoms. The following are
Read more →Underwater Welding Shielded Metal Arc Welding There are two basic techniques used today in shielded metal arc wet welding: the self-consuming technique and the manipulative or weave technique. 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
Read more →Underwater Welding : Joint Fit-Up Since most underwater tasks are more cumbersome than similar topside work, the proper positioning of large members or plates underwater for welding is also quite difficult. Positioning and fitting must be done with thoroughness and care to ensure a satisfactory weld. In underwater fillet welding, it is important that there be no gap at the
Read more →Fillet Weld. A fillet weld is a triangular weld used to join two surfaces that are at approximately right angles to each other. i.e., lap, tee and corner joints are normally welded with a fillet weld. A fillet weld should have a leg length equal to the plate thickness up to 3/8-inch plate. For plate thicknesses 3/8-inch and greater, a
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