The attached book is helpful for this.

Yes there are certain thumb rules for certain classes of alloys. In case of steels the thumb rule for annaealing/ hardening would be 1 hr/ inch. For temperiing it would be 2 Hr/Inch.

For HSLA steels it would be double i.e  4 min/ mm for hardening and 8 min/mm for tempering.

There are certain thumb rules as given by a researcher in the answer. You can find the required information about the required time in the books and handbooks on heattreatment of metallic materials.

The attached book is helpful for this.

I think there would be no such formula in principle, because there is a lot of possible types of heat treatment. Even inside one type of operation the time required may vary significantly. But if you mean some sertain kind of heat treatment there are of course some ways to calculate the time needed. For example those proposed by Anil Kumar V.

We use regimes defined by experience and it is 2-4 minutes for 1 mm of thickness. So, for plate 5 mm thick use 10-20 mins.

1 hour/inch

These empirical soaking time and heating/cooling cycle are determined based on TTT and CCT curves for corresponding alloys and desired phase at the end of heat treatment cycle. Using thumb rules as stated above is lot easier. 

I agree with Prakarsh, I recommend you look at:

http://products.asminternational.org/hbk/index.jsp

I agree with M.Brykov.

dear Anil Kumar V is there any reference for these rules or its from experimental work,because we made these rules already but we don't have any reference.

thanks dear Marcelo Pagnola, but i don't have access to enter this website

Dear Dr. Ahmed Ameed I have got the above attached book easly

ASM vol 4 

yes it is . but you must know the coefficient of  h , k , c and then you can refer to heat transfer book in order to calculate