Corrosion resistance comparation of Ni-cr alloy

H

hammerfall

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Oct 2, 2010
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this is the ni-cr alloy GNiCr40Al4 i was talking about earlier. my friend finally got it made into a knife blade. he did the test to compare the corrosion resistance with ferrous stainless alloy.

4 stainless blades was tested by the salt spary. 420, ni-cr alloy, 440c, ats34.

after 1 hour of salt spary test, all blades had showed rust except the Ni-Cr alloy. 420 and 440c was removed from test to avoid futhur damaging the blade. the GNiCr40Al3 alloy stayed in for a full 24 hour test. however they forgot the poor ats34 was also in there... and after 24 hours of salt spary, the result shows in the following images:

before%20salt%20spary.jpg


spary%20test%201.jpg


spary%20test%202.jpg


spary%20test%203.jpg


spary%20test%204.jpg


spary%20test%205.jpg


it seems 420 has better resistance than the 440c. ats34 however stayed full length of the salt spary, the sample can't compare with the 440c and 420 sample. GNiCr40Al4 had showed the best corrosion resistance out of 4 stainless alloys.

in these photos, the blade marked with chinese characters is the GNiCr40Al4 alloy.

btw, one thing i must metion again for people who had received or will receive the free test piece. the alloy after age hardening will be very resiste to wear. grind and polishing after hardening will be hell a lot pain to endure. i hope you all enjoy that!
 
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Hey, is this the Ni-Cr alloy that was developed for sub crews by the Soviets? I remember that thread caught my eye. How do we get some of this stuff to try out?

I did notice that the blades had different finishes. It looked like the Ni-Cr blade was hand rubbed, the others were not. It also had what looks like a Rc test divot, what was the hardness?
 
Salem Straub said:
Hey, is this the Ni-Cr alloy that was developed for sub crews by the Soviets? I remember that thread caught my eye. How do we get some of this stuff to try out?

I did notice that the blades had different finishes. It looked like the Ni-Cr blade was hand rubbed, the others were not. It also had what looks like a Rc test divot, what was the hardness?
Click to expand...

well, yeah this specific alloy in the picture was developped by soviet russians for their submarines. but this type of ni-cr non magnetic alloy was frist researched and developed by the americans military if my knownlodge serves right. and it was some interesting story.

there was a U-2 reconnaissance airplane got shot down at may first 1960. the direct reason caused the plane to be shot donw was a magnet niddle, it was placed under the height meter by some bad evil spy dude ^&%$#. and it messed up the meter, thus intrupted pilot's judgement on height. shortly after he took off from the military base in turkey, the russian got him below 15000 meters. the pilot survived the crash, he remembered that the meter showed above 20000m before he was hitten by russia AA missile.

shortly after that incident, the americans start to developing and researching non-magnetic alloys. the ni-cr alloy first developped by US was use for shaft on their aircraft meters in order to counter incoming magnetic interuption. later also studyed by soviets to develop their own non-magnetic alloy. however the russians also taking advantage of its interphase precipitation mechinism to provide exellent wear resistance, elasiticity, and of course corrosion resistance. it was used on those soviet russian's monstrous nuclear submarines that once made the world tremble. it was also used on their space ship.

one thing i have to admit that is the russian did win over american on this specific field of study during the cold war. their huge montrous nuclear submarines can go down 1000m below water level, that was very amazing.

anyway, thanks for reading that incoming wall of text lol. if you want a free sample to try out, you have to contact my friend at linxiachu@126.com.
 
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feel free to contact him, its better to try it out yourself than read my crapy spellings. we also need more user feed back before decide making it a blade alloy production or not.
 
my GNiCr40Al4 sword is produced, estimate month can be done!
 
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wang3 said:
GNiCr40Al4 is cow ah, my GNiCr40Al4 sword is produced, estimate month can be done!
Click to expand...

do you mean GNiCr40Al4 is cool?

a cow i believe it usually refers to the type of black and white color ox that breeded for milk production. online chinese-english translation sucks man.

a cow=

(__)　
　 /oo\\________
　 \　/　　　　 \---\
　 \/　　　 /　 \　 \
　　　\\_|___\\_|/　　*
　　　 ||　 YY|
　　　 ||　　|| 　
anyway，good luck on your sword. i hope you enjoy it.
 
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hi j. rosa

i think you need to contact my friend to get one. but i think he had sent all is piece already. and the forging process of this alloy (from ingots to bar) is quiet complicate. you might have to wait for a week or 2 until he can get new samples ready.
 
Well I don't forge myself but if your friend happens to have samples in flat stock to try for a good price I wouldn't mind trying some.
 
right now we are offering 200x40x4.5mm free test sample for more user feed backs. but unfortunatly, the last samples were shipped out few hours ago.

you need to talk to himself if you want to know the price of any specific size. his email is linxiachu@126.com.

the final market price is yet to be decided depends on the user feed back. but from the information i know, i think it should be something arround 180 us$ per kg.
 
Hmm. Thanks for the info. I sent an email with some questions. Hopefully, the others that are testing it have good feedback to report. I am really curious about the toughness of this alloy? What other tests has your friend done on the knife? Any info on toughness?
 
i got 2 pictures posted in another thread. its the graph of hardness vs aging time/temperature.

well, its very hard for me to translate the etire research papers lol. so i guess i will try answer whatever i can.
 
Hi - I will take the papers in Chinese. I believe I can have them translated by some friends locally. Thank you.
 
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