Equivalence of Heat Treatment Specs?

'Morning, my name is Ken and I am a quality tech for an aerospace machine shop in Corona CA. I would like to know if heat treat spec AMS2759/3 Rev E supersedes AMS5643 or is equivalent?

Kenneth, they're way different!

AMS5643 is the specification for the METAL: for the bars or forgings you buy from the guy who sells 17-4 stainless steel. As such, it has things like "the composition shall be this" and "no more than 5% delta ferrite". It also has heat treat CAPABILITY requirements, so that if I buy the stuff and age it properly to condition H1025, I'll get a certain level of tensile and yield strength and elongation and reduction of area.

AMS2759/3 is the HEAT TREATING specification, meaning it says "the furnace you use has to have a uniformity of ± 10 F for aging, and ± 25 for solution treating" and notes that the time for aging at 1025 F to get the H1025 condition is 4 hours, although you're allowed more if you want to lower the hardness to a tighter range. It deals only with the heat treatment of the 17-4 you bought per AMS5643, or other precipitation hardening stainless steels.

Hope this helps!

AMS2759 is for generic heat treatment of steels, whereas AMS5643 is alloy specific.