Stainless steel is subject to intergranular corrosion at the elevated temperatures we encounter during welding. The chrome in the stainless combines with the carbon to form chrome carbide.
One of several solutions to the problem is to alloy the stainless steel with a strong carbide former.
The best is columbium, but sometimes titanium is used. The carbon will now form columbium carbide rather than going after the chrome to form chrome carbide.
The material is now said to be stabilized because the chrome is still present to provide corrosion resistance.