168
M. V. Mehta et al.
Fig. 3 Application ranges of between Hastelloy alloy C-276, C-4, C-2000, C-22, VDM Alloy 59,
and Inconel 686 [3]
weld overlay find application in heat exchanger tube sheet, shafts as well as local
repair and refurbishment of equipment [39].
Weld overlay is generally applied in two cases; one is hardfacing and the second
one is corrosion-resistant application. Generally, corrosion resistance is readily
applied to carbon steel, low alloy steel, and other materials with pure Ni chemistry, nickel–copper alloy, nickel–chromium–iron alloy, nickel–molybdenum alloy,
and nickel–chromium–molybdenum alloys. For defect-free weld, clean base metal
properly and remove all oxides and foreign materials before starting weld overlay.
Another problem is high S and P content in base metal which leads to cracking in
nickel-based weld overlay. Solution for cracking is sacrificed layer, add barrier layer,
and design low S and P structure and control dilution with weld technique [3].
A leading factor in weld overlay is controlling dilution. Dilution lowers the chemical which contains corrosion-resistant alloy which affects corrosion-resistant properties; the most effective way to lower the dilution is multiple weld overlay, but as
the number of weld overlay passes is increased, the cost of manufacturing increases
and microstructure changes are observed, so another way to control dilution is by
controlling welding techniques and welding parameters. Dilution can be controlled
by proper control on welding techniques such as stringer bead weld overlay and the
overlap of the weld bead and also by welding parameter selections, which target
lower heat input to the base metal without affecting the bonding strength. Dilution
can be controlled by using welding processes that have a low depth of penetration.
For example, the change in transfer mode reduces the depth of penetration in the
GMAW process [39–41].
M. V. Mehta et al.
Fig. 3 Application ranges of between Hastelloy alloy C-276, C-4, C-2000, C-22, VDM Alloy 59,
and Inconel 686 [3]
weld overlay find application in heat exchanger tube sheet, shafts as well as local
repair and refurbishment of equipment [39].
Weld overlay is generally applied in two cases; one is hardfacing and the second
one is corrosion-resistant application. Generally, corrosion resistance is readily
applied to carbon steel, low alloy steel, and other materials with pure Ni chemistry, nickel–copper alloy, nickel–chromium–iron alloy, nickel–molybdenum alloy,
and nickel–chromium–molybdenum alloys. For defect-free weld, clean base metal
properly and remove all oxides and foreign materials before starting weld overlay.
Another problem is high S and P content in base metal which leads to cracking in
nickel-based weld overlay. Solution for cracking is sacrificed layer, add barrier layer,
and design low S and P structure and control dilution with weld technique [3].
A leading factor in weld overlay is controlling dilution. Dilution lowers the chemical which contains corrosion-resistant alloy which affects corrosion-resistant properties; the most effective way to lower the dilution is multiple weld overlay, but as
the number of weld overlay passes is increased, the cost of manufacturing increases
and microstructure changes are observed, so another way to control dilution is by
controlling welding techniques and welding parameters. Dilution can be controlled
by proper control on welding techniques such as stringer bead weld overlay and the
overlap of the weld bead and also by welding parameter selections, which target
lower heat input to the base metal without affecting the bonding strength. Dilution
can be controlled by using welding processes that have a low depth of penetration.
For example, the change in transfer mode reduces the depth of penetration in the
GMAW process [39–41].