Ni-Cr alloy heat treat!!!

[hammerfall]

ok, my friend called me 5 am in the morning, ask me to make a heat treat note for people had already received the GCrNi40Al4 sample. it was a good dream i am in full of pretty girls, and i don't think i can get back to the same dream again after i finish this post...

well, the heat treat can't be easier...cold work that sheet into a shape of knife. then aging at 630 C for 5~7 hours. the temperature need to be controled within ±5 range. after the aging you will get a blade of HRC 57~58.5. finally make the finishing polish.

the finish will be hell a lot of pain to endure especially early polish...you will enjoy that. and good luck you bladesmith!!!!

 

[hammerfall]

add something, that aging temperature is between 610~650C. 630±5 is not required that accurate. keep the temperature in range of 610~650C for 5~7hours, you will get the good enough result.

 

[Salem Straub]

Let cool in air? Will a quench affect it in any way other than to cool it off?

I know it's precipitation hardening so quenching won't make it any harder.

 

[hammerfall]

sorry, i forgot mention the cooling rate.

after age hardening air cool will be fine.

but in order to minimum the stress, furance cool is perfered. And do not worry about oxidation, this stuff resiste oxidation very well even at 1200 C. so you can pretty much do a "almost finished blade" before aging. 630 C for 5 hours won't make much difference on the blade surface.