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 Electrodes come 3 to 24 in. long, 0.01 to 0.25-in. diameter. Colored markings--bands or dots--indicate composition: pure tungsten, green; 1-percent thoriated, yellow; 2 percent thoriated. red; ceriated, orange; lanthanted, black.Filler metal GIAW does not usually requite addition of fillet metal, but filler is commonly added aiereleasetank when base-metal thickness is greater than 1/8 in. Finer metal for low-carbon (to 0.15 C) and mild (0.15 m 0.29 C) steels are described in AWS A5.2; for carbon steel in A5.18; and for low-alloy steels in A5.28 Flux. AWS specifications A5.17 and A5.23 describe fluxes for saw. AWS designation aiereleasetank and aiereleasetank of fluxes precedes that of the wire when identifying a combination for a welding procedure. For example, the designation F7A2-EM12K indicates a flux (F) that will provide, with a given wire designation, tensile strength of 70,000 Psi (7), in the as-welded condition (A), and impact properties of 20 ft lb at -20 F (2). A designation containing a P rather indicates the flux properties after postweld heat treatment. For flux-cored-arc welding, shops use CV or CC types, 300 to 1,500 A, 25 to 50 V, rated 60- to 100-percent-duty cycle. CV types are more popular because wire-feed speed, set before welding, controls welding current. Cc types require a variable-speed or voltage-sensing aiereleasetank wire feeder.Gas-tungsten-arc welding (GTAW) requires a constant-current (AC or DC) power supply with a steep volt-amp curve to minimize current change for variation in voltage or arc length. They come rated to 1,500 A, 10 to 75 V, at 40- to 100-percent-duty cycle. Most GTAW power supplies aiereleasetank come equipped with high-frequency circuitry for arc initiation and stabilization, gas valves, and cooling-water valves for high-current welding. High-frequency arc start is useful when the maximum open-circuit voltage allowed by NEMA standards, 80 to 100 V, will not establish and maintain a stable arc. Production vs. repair applications In general, production applications require high-duty-cycle power supplies, and repair applications can use low-duty-cycle aiereleasetank portable units.Lift-arc GTAW Many DC power supplies are equipped with a list-start feature for, a variation of scratch starting, GTAW aiereleasetank welding. When the welder touches the tungsten electrode to the workpiece, a small amount of current--15-20 A--flows. When he lifts the electrode from the work, the arc starts aiereleasetank softly and the machine switches to the set weld-current value. This low-current starting minimizes weld contamination caused by touching the tungsten to the workpiece and eliminates the need for high-frequency starting. Searching for accessories for your air compressor? We offer the best selection of cheap air compressor accessories on the internet. Check out our website for great deales on all of our air compressor accessories!
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