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Topic
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General Description of Subject Matter
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General welding safety
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Safety measures, safe handling of gas cylinders, safety regulations for oxyacetylene welding,
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Essentials of shielded metal arc welding technology
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Basic concept of electric arc welding, metal transfer, and arc length
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Heat input and distribution
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Heat input, heat distribution, weld quality inspection, common welding mistakes
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Preparation of the pipe joint
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Preparation of the pipe joint, cleaning joint surfaces, fitting up the pipe, tack welding, the keyhole, the hipping technique, stopping the weld.
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Uphill welding the root bead on heavy-wall pipe (5G) position
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The root bead, general procedure for uphill root bead welding, the keyhole, starting the root bead, uphill welding the root bead, vertical uphill welding the root bead, flat welding root bead, tie in procedure, inspect the weld.
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Welding the root bead by the gas tungsten arc welding process.
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The GATW process, equipment, preparation of root bead, procedure for welding the root bead, root bead-pulse current-gas tungsten arc welding.
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The intermediate and cover passes
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Multiple layer welds, preparation of root bead, the current setting, electrode angle, welding the intermediate passes, start and restart, low hydrogen electrodes.
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Welding thin wall pipe
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Uphill welding, downhill welding, welding the tacks, hot pass, intermediate passes, downhill welding heavy and large diameter pipe, depositing root bead, heavy wall pipe, large diameter pipe, depositing the hot pass, filler passes and their sequences, cover pass.
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Horizontal pipe welding (2G)
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Preparation for welding, horizontal welding of the root bead, root bead with low hydrogen electrodes, the second pass, third and forth passes, fifth, sixth and seventh passes (cover pass)Alloy steel in high temperature services, welding steel for low temperature services ( cryogenic services), nickel steel of the 9% grade.
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Welding complicated pipe joints
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Welding variations for complicated pipe joints, uphill welding with pipes in an angular (6G) position, full lateral joint, tee joint intersection on top, tee joint with intersection on bottom, tee joint with intersection at the side, Y joint.
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Introduction to welding metallurgy
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Properties of metals, ultimate tensile strength, yield strength, hardness, strain, strength, harden ability, toughness, brittleness, malleability, fatigue, grain structure, structural characteristics of steel, the iron carbon diagram, grain size, size change, alloying elements in steel, stress relieving, structure of the weld, structure of the weld and the weld affected zone, residual stresses and distortion in welds.
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Distortion in pipe welding
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Typical welded pipe fabrication distortion, pipe welding and understanding distortion.
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Pipe welding defects
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Arc strike cracking, under bead cracking, restraint cracking. Welding faults and their prevention, weld repair, first step repair, second step repair, removal of defects.
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Fitting up pipe
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Fitting up pipe procedures, tools required, pipe to pipe fit-up, welding pipe parts to pipe, steps to fitting up pipe, alignment of flanges, 90 degree elbows, 45 degree elbows, vertical pipe alignment, perpendicular pipe alignment.
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Qualification of the welding procedure and the welder
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Qualifying a procedure, qualifying the welder, perfect weld requirements, bend test.
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