True or False: Sensitization of stainless steel can occur in the heat-affected zone (HAZ) of a weld.

Sensitization of stainless steel refers to the phenomenon where chromium carbides precipitate at the grain boundaries when the steel is heated to certain temperature ranges, often during welding processes. This typically occurs in the heat-affected zone (HAZ) of a weld because that area experiences elevated temperatures, leading to the potential for carbon to bond with chromium, thus depleting the chromium content at the boundaries and making the steel more susceptible to corrosion.

In stainless steels, particularly austenitic stainless steels, sensitization is a significant concern because the protective chromium oxide layer that provides corrosion resistance can become compromised when the chromium is depleted. Therefore, the statement about sensitization occurring in the heat-affected zone during welding activities is accurate.

The other provided options either mischaracterize the mechanisms of sensitization or the types of steel affected. Sensitization is not restricted to carbon steel or solely limited to austenitic steels, though it is primarily discussed in the context of austenitic stainless steels due to their widespread application and importance in industry.