Hastelloy Heat Treatment

Solution annealing of Hastelloy is about bringing precipitates back into solution. To do this, the part is heated to a high temperature and held until the structure is homogeneous. Then you have to quench quickly so the unwanted phases can't form again. If you mess that up, you'll get a brittle structure that cracks during welding or in service. The exact temperatures and times depend on the alloy, so check the data sheet. When in doubt, ask rather than ruin an expensive part.