Archive for 2012

Oxy-Acetylene Welding of Steel & Iron

Oxy-Acetylene Welding of Steel & Iron There are many different varieties of steel, but from a welding standpoint they may be classified by their carbon content. Those having a high carbon content are called hard steels; those with a low carbon content, soft steels. Wrought iron may be treated the same as mild or soft steel. To be sure, there

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Underwater Shielded Metal Arc Welding Electrodes

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

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Underwater Welding : Introduction

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

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Exothermic Electrodes : Cutting Techniques

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

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Steel-Tubular Electrode Cutting Technique : cast iron and non-ferrous metals

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

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Tungsten (W)

(a) General. Tungsten is a hard, heavy, nonmagnetic metal which will melt at approximately 6150°F (3400°C). (b) Tungsten Uses. Tungsten is used in making light bulb filaments, phonograph needles, and as an alloying agent in production of high-speed steel, armorplate, and projectiles. It is also used as an alloying agent in nonconsumable welding electrodes, armor plate, die and tool steels,

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Chromium (Cr)

Chromium is an alloying agent used in steel, cast iron, and nonferrous alloys of nickel, copper, aluminum, and cobalt. It is hard, brittle, corrosion resistant, can be welded, machined, forged, and is widely used in electroplating. Chromium is not resistant to hydrochloric acid and cannot be used in its pure state because of its difficulty to work.  Uses. Chromium is

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Properties of Metals

a. Definitions. All metals fall within two categories, ferrous or nonferrous. (1) Ferrous metals are metals that contain iron. Ferrous metals appear in the form of cast iron, carbon steel, and tool steel. The various alloys of iron, after undergoing certain processes, are pig iron, gray cast iron, white iron, white cast iron, malleable cast iron, wrought iron, alloy steel,

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Oxygen and Oxygen Production

a. General. Oxygen is a colorless, tasteless, odorless gas that is slightly heavier than air. It is nonflammable but will support combustion with other elements. In its free state, oxygen is one of the most common elements. The atmosphere is made up of approximately 21 parts of oxygen and 78 parts of nitrogen, the remainder being rare gases. Rusting of

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Oxy-Acetylene Cutting

Oxy-Acetylene Cutting Oxy-acetylene torches have an attachment for cutting, which can be attached to the welding torch. Here the flow of oxygen is controlled a lever. In planning the job, have the tanks firmly secured to prevent tipping over, the hose should be BEHIND you so as to protect it from damage due to flying sparks. Make certain also that

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