NativePaul
11-07-2016, 10:10 PM
Hi all, I am wondering if anyone that heat treats their props is solution annealing them before age hardening and if so how much difference does it make from just age hardening, and how do you do it?
I have bent a few blades backwards in SAWs and want to harden them, but I don't have the facilities to solution anneal them at home, and don't know if there is something that I can knock up fairly cheaply to do it, if I should send them out to a specialist, If it doesn't add that much strength and isn't needed, or even if it would warp the blades of my finished props and must be done before sharpening.
From http://www.matthey.ch/fileadmin/user_upload/brochure/AT0015-0311_-_Tech_Briefs_-_Heat_Treating_Copper_Beryllium_Parts_LMSA.pdf
The standard age hardening cycle for the high strength casting alloys, both annealed and as cast, is three hours at 625-650°F (320-340°C).
However, to develop the highest strength for the as cast products, a separate solution anneal should precede the age hardening.
If solution annealing is required, it is a high temperature soak: 1450°F (790°C) for the high strength alloys and 1650°F (900°C) for the high conductivity alloys. Annealing must be carefully controlled as excess time or temperature may cause grain growth. Solution annealing should be immediately followed by a water quench. As a precaution, large quantities of metal should not be annealed without first conducting a furnace simulation test. Thin sections, such as finewire, require an annealing time of about 3-5 minutes. Fifteen minutes to one hour is required for thin walled tube and small castings. Heavy sections (above about one inch) usually require 1-3 hours. A heat up time of one hour per inch of thickness must be added to the soak time. Because most salts will attack copper beryllium at temperatures in the solution annealing range, solution annealing should not be performed in a salt bath. When peak aging copper beryllium castings and weldments, the customer must always solution anneal prior to age hardening. However, if peak properties are not required, castings can be age hardened from the as cast condition without the solution anneal.
I have bent a few blades backwards in SAWs and want to harden them, but I don't have the facilities to solution anneal them at home, and don't know if there is something that I can knock up fairly cheaply to do it, if I should send them out to a specialist, If it doesn't add that much strength and isn't needed, or even if it would warp the blades of my finished props and must be done before sharpening.
From http://www.matthey.ch/fileadmin/user_upload/brochure/AT0015-0311_-_Tech_Briefs_-_Heat_Treating_Copper_Beryllium_Parts_LMSA.pdf
The standard age hardening cycle for the high strength casting alloys, both annealed and as cast, is three hours at 625-650°F (320-340°C).
However, to develop the highest strength for the as cast products, a separate solution anneal should precede the age hardening.
If solution annealing is required, it is a high temperature soak: 1450°F (790°C) for the high strength alloys and 1650°F (900°C) for the high conductivity alloys. Annealing must be carefully controlled as excess time or temperature may cause grain growth. Solution annealing should be immediately followed by a water quench. As a precaution, large quantities of metal should not be annealed without first conducting a furnace simulation test. Thin sections, such as finewire, require an annealing time of about 3-5 minutes. Fifteen minutes to one hour is required for thin walled tube and small castings. Heavy sections (above about one inch) usually require 1-3 hours. A heat up time of one hour per inch of thickness must be added to the soak time. Because most salts will attack copper beryllium at temperatures in the solution annealing range, solution annealing should not be performed in a salt bath. When peak aging copper beryllium castings and weldments, the customer must always solution anneal prior to age hardening. However, if peak properties are not required, castings can be age hardened from the as cast condition without the solution anneal.