Titanium carbonitride stabilization

Titanium stabilizes austenitic steels by binding carbon and nitrogen. This prevents chromium from being depleted at grain boundaries, which would lead to intergranular corrosion or knife-line attack. When welding, you need to make sure the weld metal gets enough titanium, otherwise the weld loses its protection. The exact heat treatments and cooling times are not the key thing – what matters is that you don't unnecessarily bring stabilized material into the critical temperature range.