Steel Design > Steel Materials prompts you with the following dialog.
It allows you to define steel strength properties for the existing materials. The strength properties include:
•Steel yield stress Fy
•Steel rupture stress Fu
If standard materials are used in Tables > Material Data, these strength properties will be set automatically. You may override these properties prior to performing steel design. No steel design will be performed on a member if its modulus is not close (within 10%) to 29E3 ksi. You should not modify materials that are not steel on this dialog.