Nickel High-Temperature Oxidation Resistance
Property of nickel alloys to inhibit the progressive attack of oxygen under thermal stress through the formation of dense chromium or aluminum oxide protective layers.
Nickel-based alloys protect themselves at high temperatures by forming a dense chromium or aluminum oxide layer on the surface. That's the real protection against oxidation and corrosion. When welding, you have to be careful not to damage this protective layer or overheat the alloy. If the oxide layer can't form properly, the material becomes porous and loses strength. Before welding, clean the joint areas and remove grease, otherwise dirt burns and pulls in carbon. During welding, keep heat input low and watch the interpass temperature, otherwise you risk cracks and microstructure changes.