I believe the intent of the annealed condition is to improve machinability, which would then be followed by heat treatment to obtain the desired allowable tensile stress. Otherwise, there’s no point in specifying a relatively expensive alloy steel when the same result could be obtained in cheaper grades.
Tempering
AISI 4140 alloy steel can be tempered at 205 to 649°C (400 to 1200°F) depending upon the desired hardness level. The hardness of the steel can be increased if it has a lower tempering temperature. For example, a tensile strength of 225 ksi can be achieved by tempering at 316°C (600°F), and tensile strength of 130 ksi can be achieved by tempering at 538°C (1000°F).
Yesterday I heated the three 4140 studs to 750-800 degrees F then quenched them in oil. I was all set to start torquing them down but realized that when I changed the one hex headed bolt that had replaced a stud in its past, I didn’t purchase a nut for it. So while I wait for nuts to arrive, I’m spending time changing out grommets on the undercarriage.
It’s funny the things you forget when you’re in a hurry!