HAYNES 625 alloy is readily welded by Gas Tungsten Arc (GTAW), Gas Metal Arc (GMAW), electron beam welding, and resistance welding techniques. Its welding characteristics are similar to those for HASTELLOY® X alloy. Submerged-Arc welding is not recommended as this process is characterized by high heat input to the base metal and slow cooling of the weld. These factors can increase weld restraint and promote cracking.
Base Metal
Preparation
The joint surface and adjacent area should be thoroughly cleaned before welding. All grease, oil, crayon marks, sulfur compounds, and other foreign matter should be removed.
It is preferable, but not necessary, that the alloy be in the solution-annealed condition when welded.
Filler Metal Selection
Matching composition filler metal is recommended for joining 625 alloy. For dissimilar metal joining of 625 alloy to nickel-, cobalt-, or iron-base materials, 625 alloy itself,
230-W™ filler wire, 556® alloy, HASTELLOY S alloy (AMS 5838), or HASTELLOY W alloy (AMS 5786, 5787) welding products are suggested, depending upon the particular case. Please see publication H-3159 for more information. Preheating, Interpass Temperatures and Post-Weld Heat
Treatment
Preheat is not usually required so long as base metal to be welded is above 32°F (0°C). Interpass temperatures generally should be low. Auxiliary cooling methods may be used between weld passes, as needed, providing such methods do not introduce contaminants. Post-weld heat treatment is not normally required for 625 alloy. For further information please consult publication H-3159. |
