Need assist time temperature parameters Larson-Miller vsHollomon-Jaffe

[2minto]

looking at the time temperature parameters Larsen-Miller vs Hollomon-Jaffe they both appear to be different arrangements of the same equation? is this correct?
LM = T (log tr + C)
HJ = T (C + log (t))

The recommended values of constant C range from 20-22.
For tempering some have used C = 18 (for CrMo P22) is there any formula or table data for C values?

 

[metengr]

looking at the time temperature parameters Larsen-Miller vs Hollomon-Jaffe they both appear to be different arrangements of the same equation? is this correct?

Yes.

 

[kclim]

Thermally-activated processes (e.g. creep, softening) can generally be reduced to the LM/HJ type form.

Was just flicking through a copy of Viswanathan, Damage Mechanisms and Life Assessment of High-Temperature Components; a C value of 20 for P22 is used almost exclusively.