Hey Hammerfall, what's the HT data on GNiCr40Al4 again?

[Salem Straub]

I'm about to cut a folder blade out, and need the time and temp for the precipitation hardening so I can send it out and get that done. I'm looking forward to this! Finally making myself a framelock to carry, and trying out this superalloy for a blade too. Thanks in advance, Hammerfall. I'd'a sent you a PM or email but apparently not an option.

[bladsmth]

1150-1200F (630-650C) for six to ten hours.

[hammerfall]

is that a cold rolled bar? if it is, i need to know how much the deformation before i can give the aging temperature.

if its not, then 630°C for 5~6 hours. the hardness should be arround Rc 57. 10mm x 10mm x 55mm standard unotched impact should be no less than 32j.

this alloy feels different than ferrous based steel. from the fed backs i had received, it is said its difficult to be grinded to very sharp. if it is possible try it yourself and grind it to a razor sharp. email me some info of how it preforms as a knife blade. it has amazing wear resistance as ball bearing tool, but i am not sure how much benifits will it bring to a knife.

iwalkthehells@hotmail.com is my email.

[bladsmth]

Hammerfall,
I would love to find a supply for GNiCr40Al4 that has been cold rolled 10:1. It should make really hard and tough knives. Do you know of a supplier?

[Salem Straub]

Thanks a bunch, guys. Hammer, I'll sure send you my feedback as soon as I have some.

[Salem Straub]

OK, 1170 F for 6 hours. Then, air cool, or let cool with the furnace, or does it matter?

[hammerfall]

i know laboratories can manufacture it with small amount. but the shipping price from china to usa is expansive and will take long time(a month with good luck). and the alloy itself has a high cost since it has 55%Ni.

due to its high strength in its solution states, usually it can be rolled from 10mm maxium thickness to 1mm thickness. thats 10:1, but 1mm would be useless for a knife. i have seen sheet cold rolled into 3.5mm thickness which bring up hardness to RC 64~65. 67hrc can be achieved when reduced to 1mm, but with 1mm in thickness i am not sure what else can be made other than razor blades.

[hammerfall]

OK, 1170 F for 6 hours. Then, air cool, or let cool with the furnace, or does it matter?

it doesn't matter.

one thing need to be careful, the alloy itself does not cool easy like carbon steel. it takes almost double time than carbon steel cooling from 600C to room temperature. i got my finger burnt a few time. just make sure its cold before you grab it with your bare hands lol.

[Nebulae]

please tell us how this stuff works I am curious.

[bladsmth]

The alloy is 54% nickel, 40% chromium, and 4% aluminum. The metal can be precipitation hardened to a moderate hardness, and cold rolled to shear the matrix and produce relatively high hardness.
Hammerfall can explain it in greater depth.

The knife I made from Hammerfall's sample was super tough and plenty hard for a working knife. It isn't a razor blade, but will work just fine for hunting and general use.
It does require a well controlled oven to do the HT.

[Salem Straub]

Needless to say, it's also about as close as you can get to corrosion proof.

[Rick Marchand]

Lookie what I got gifted in the mail today from a madman in Jersey...

Look familiar?

[Salem Straub]

Awesome! Grind that stuff with a sharp belt! Mine turned out as a pretty darn good blade "steel"... I'll be interested to see what you do with it.

[hammerfall]

it looks like one of the free test sample xia'chu sent a year ago across the sea lol. that funny hand writing looked formilar. did you just receive it or was it from someone else?

btw, be careful when you do the grinding. this thing do not turn in color even if the temperature hit 1000f +. and it cools pretty slow. many people got their finger burnt during the grind lol.

[Rick Marchand]

I just got it yesterday from Aldo along with two bars of L-6. How does he stay in business giving away all his steel?... not that I'm complaining. What a guy.

Hammerfall, two questions, sir...

1. What were the results of your cold working experiment? Where you able to get a hardness differential?
2. What would you like to see done with this piece?

[hammerfall]

cold work increasing the hardness after aging. it can either be done by cold rolled sheet or cold forge an edge from the sheet in its solutioned condition. i recomanded cold rolling tho. cold forge an edge is albe to get a differential hardness, but i worry about more problem will be intruduced during the forging than benifits.

you have to be the one decide what to make. well consider this is an alloy having 57~58hrc, toughness of 32j/cm2(55x10x10mm unnotched impact J). almost immune to rust when using below temperature of 500f. no cold embrittleness(good for people live in alaska and sibria). non magnetic as well. extramly good mirror finishing ability.

the cons are: expansive to make. and hard to forge(as ingots). hard to work. the 32j toughness is ok, better than most of stainless steel of same hardness. yet not good enough to make a sword size blade. 58hrc is good hardness, however many customer may perfer 60+ for their knife...

thats what i can think for now. try your imagination to make a knife best fit for it.

[Rick Marchand]

What about hot forging?... out of the question?

[hammerfall]

you can hot forge. however it does not increasing the hardness and strength after aging.