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 Hardfacing alloys contain as base elements typically iron, nickel, or cobalt, to which metallurgists add varying amounts of carbon, aircompressorkots chromium, molybdenum, tungsten, silicon, manganese, vanadium, and boron. To raise hardness, the primary property for wear resistance, alloy designers add elements that either form hard constituents (carbides, borides, or Laves phase), or that strengthen the matrix by going into solid solution. Carbon content determines toughness and abrasion resistance--as carbon rises, abrasion resistance increases and toughness drops. Chromium forms aircompressorkots carbides, increases corrosion resistance, and adds high-temperature strength. Tungsten, a potent carbide former, also boosts high temperature strength, as does cobalt. Tougheners include nickel and manganese. Boron forms hard wear-resistance borides. Welding-site conditions and welding-wire diameter govern efficiency and size of power supply required for a job. Select a 100-A unit that runs from single-phase 115-V aircompressorkots input for low-duty-cycle welding of sheet to l/s in. thick, feeding wire to 0.030-in. diameter. Medium-duty power supplies, 150-200 A, normally take single-phase 220-V input to weld steel to 3/16, in. and 0.035-in. wire at low-duty cycles. For aircompressorkots high-duty cycles, as in mechanized welding, select a 250-A machine, single or three-phase input at various voltages-these weld material to 1/2 in. thick with wire as large as 0.045-in. diameter. Taking three-phase input only and wire up to 1/6-in. diameter, 400-A units serve for mechanized continuous-welding applications. For pulsed GMAW, shops use inverter and transistor power sources, constant-current or constant-voltage, that offer independent setting of pulse parameters. They employ synergic controls preprogrammed for a range of wire-feed speeds-the operator sets only one dial, for average current. High-deposition electrodes. These contain iron-powder additions in the coating to raise deposition rate. Designations: EXXX4, EXXX7, EXXX8.For fastest deposition, use the largest aircompressorkots diameter possible for an application-the thicker the electrode, aircompressorkots the greater its current-carrying aircompressorkots capacity and the higher the deposition rate. Welding out of position and overhead, select a small diameter electrode to enable welders to reach into narrow root aircompressorkots openings.Gas-Metal-Arc Welding (GMAW, MIG)GMAW typically uses solid wire, spooled or reeled, for continuous feeding to the gun; diameter, 0.030 to 1/16 aircompressorkots in. typically, although wires as small as 0.020 in. and as large as 1/8 in. are sometimes used. AWS lists specifications for filler wires of copper and its alloys, aluminum and its alloys, surfacing alloys, nickel and its alloys, titanium and its alloys, carbon and low alloy steels, magnesium alloys, and zirconium and its alloys. 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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