does anyone know how to anneal the 4150-steel

[Tasev]

I have a problem with annealing of the 4150 steel, I dont have information about the temperature and the time of culling of the pieces in the oil.
I want to have a smooth surface, with high quality and a hardnes no less than 50B.
Please describe me the process in a short steps.
Thanks a lot.

 

[TVP]

One method for annealing 4150 is to heat to 830 C, furnace cool quickly, cool slowly from 745 C to 670 C (cooling rate = 8.5 C/hour) for 8.6 hours. Another option is to heat to 830 C, cool quickly to 675 C and hold for 6 hours.

 

[unclesyd]

Here is the method that I use.

Heat to 1525F furnace cooled 20F per hour to 1190F, air cooled.