Inconel cladding for tube is a cost-effective engineered solution
against corrosion/ erosion attacks from combustion products in
boilers and from the hot, exhaust flue gas stream in waste heat
recovery systems. Inconel Cladding technique extends the operational life of tubes
and waterwall panels, thus avoiding or delaying costly
replacements.
Compared with other surfacing methods, gas shielded surfacing has
the following advantages:
(1) Gas shielded welding is a kind of open arc welding. During the
welding process, the heating and melting of arc and molten pool can
be clearly seen, which is convenient to find problems and timely
adjust, so the welding process and weld quality are easy to
control.
(2) Gas shielded welding usually does not need to use tubular
welding wire, so there is no slag in the welding process and no
slag cleaning after welding, which saves the auxiliary labor hours
of slag cleaning and reduces the welding cost.
(3) Wide range of application, high production efficiency, easy to
carry out all-position welding and realize mechanization and
automation.
(4) Suitable for welding most metal and alloy, most suitable for
welding carbon steel and low alloy steel, stainless steel, heat
resistant alloy, aluminum and aluminum alloy, copper and copper
alloy and magnesium alloy.
There is a wide range of weldable metal thicknesses, with the
thinest about 1mm and the thickest almost unlimited.
(5) The adaptability is also strong, and the welding efficiency is
the highest when flat welding and horizontal welding.
| | Steel clad with Alloy 625 |
Membrane wall in combustion room – lower area | | |
Membrane wall in combustion room – higher area | | |
| | |
| » Pipe walls and single tubes in P235GH, 15Mo3, 13CrMo44, 10CrMo910 |
| » Alloy 622 (US), alloy 625, alloy 686 (super heater tubes)
» Coating alternatives under investigation: metal powder, ceramic, galvanizing |
| » 4-component shielding gas: He = 32 %, H2 = 2 %, CO2 = 0.05 %, remainder Ar » Alternative choices of shielding gas |
| » GMAweldingequipmentwithpulsed-currentpowersources » Automatic burner processing |
| » Vertical down position preferred, layer width 15 - 20 mm |
| » On-site in the boiler with mobile welding equipment, minimum wall
thickness 3 mm » Welding in the workshop weld metal overlay on new pipe walls and
single tubes |
| » Overlay thickness 2 mm » Two layers preferred » Sandblastingoftheweldingsurface » Water circulation in the tubes » Content of Fe in welding surface < 5 % » Content of Fe in welding material < 1 % » Consider shrinkage » End of cladding round-welded with TIG, notch-free
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