Casing Design Loads For Weights, Grades & Couplings
Once the Casing Seating Depths and the Casing Size of each casing string are established, the weight, grade, and couplings used in each casing string can be determined via the casing design loads cases.

Loads Affecting Casing Strings

In general, each casing string is designed to withstand the most severe loading conditions anticipated during casing placement and the life of the well. The loading conditions that are always considered are Casing Burst, Casing Collapse, and Casing Tension.
https://www.drillingmanual.com/drilling-casing-design-grades-weights-connections/