Does SteamID expire after some time?

[mohammd-s-m]

In my code, a mechanism is implemented that receives the username and password for the first login. And after the login operation, it saves the SessionData class in json format in a file, and for the next time, instead of login, it uses the SteamID field of this class to do things like load inventory and other things by sending a webrequest to Steam with the get method.

Considering that I haven't tested this code yet, my question is, does this process work properly? If we just use the same SteamID every time without logging in, won't there be a problem?