Annealing temperature with induction??

[itchyTF]

I believe a fellow on here (Webster, I think) has commented that proper annealing is a function of time AND temperature. Since induction heating is faster should the brass be heated to a higher temp? If so, are there any graphs available showing the time/temp relationship? A .223 case on my induction unit will get up to 750 deg in about 1.2 seconds. Should it go higher for such a short period of time?

 

[Bob L.]

The only curves I have found relate tensile strength and elongation to temperature for an annealing time of 1 hour. I have seen some curves which relate grain size increase to time, but these start at 10 minutes and continue on up in time friom there.

I would be very interested in seeing the time and temperature relationships that the cartridge case manufacturers use, but I believe those are proprietary.

The range for annealing temperatures for commercial suppliers of C26000 brass (cartridge brass, 70-30 nominal) is 800-1400 deg. F. I would say that you should be looking for 800 deg, F. as a minimum, based on this.

How are you measuring your temperature? If you are using 750 deg. Tempilaq, remember when it melts, you are assured only that 750 deg, F. is the minimum temperature reached. The actual temperature can be much higher.

Please let us not start another annealing flame war. I am only trying to answer the questions to the best of my ability.

Bob

 

[itchyTF]

I certainly am not interested in starting an annealing war, just looking for real data. I realize melted Tempilaq just indicates you reached that temperature but nothing about how much higher it went. I have 750 and 850 as well. I just don't know what the target should be for such a short "burn".

 

[Bob L.]

My remark about starting a war wasn't directed at you. I could tell you were just looking for real data. I have seen some other threads on annealing methods get ugly quickly, however.

I have not had any luck finding real data after searching pretty diligently for months. Hopefully, someone else can help both of us.

Bob