There "may" be some relationship to the 650� temperature as this is in Fahrenheit while the chart you posted above is in Celsius. You just can't see exactly where the break points are.
I just don't understand why everyone tries to make annealing so complicated. It's not.
the 800-1400 degree F corresponds with 425-750 C, which brackets the "sress relieving zone" in the graph above. 300 C (the top end of the "stress relieving" is 570 F.
So what we see recommended doesn't match the engineering data or engineering terminology.
But it works. FWIW, Dutch.
