If you'd like to generate a Steam key, first go to members.iracing.com, then Account and scroll to the bottom of the page and click GENERATE STEAM KEY:
Open the Steam App, and in the top-level menu, click Games, and then click Activate a Product on Steam.
You will then see this screen, click Next
Read and agree to the Steam terms and conditions
Then enter your product code(Steam Key) and click Next.
You will then be prompted to download iRacing to the Steam app. Click Next.
After iRacing is installed to Steam, you can then go to your Steam Library, click on iRacing and choose PLAY, then Choose Play using the Beta Interface and click Play.
Also double check that your Steam overlay is enabled. You can do this in the UI by clicking your helmet, then settings
and also in Steam 1) On your Steam client, click Steam in the upper left corner, then click Settings. 2) Click In-Game, then make sure Enable the Steam Overlay while in-game is checked.
Doing all of the above, will allow you to use iRacing through Steam and logs your game time within Steam.
Please remember that since you initially purchased iRacing directly through iRacing, all purchases must also be made through iRacing and not through Steam. Steam and iRacing have two completely separate purchasing processes.
Linking a Steam key does not allow Steam purchases.