Nickel vs Nickel mistery

qwerkus

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Hello,

I have a question regarding nickel strips. Bought strips from 2 different sellers, one is 0.15*28mm (5Meters) and the other one is 0.2*30mm (10m) - all two supposedly 99.7% nickel.
Color and finish looks identical. Both passed the salt water test, so it ain't plated steel. Yet the 0.2mm strip feels actually a lot more ductile than the 0.15mm. How could that be possible ? Are there other fake nickel alloys around ? How to identify which metal those strips are made of ? I measured the resistance of a piece of each strip cut to the same length, and get 2.5Ω for 0.15*28mm and 1.5Ω for 0.2*30mm.
Alternatively, could it be that the 0.2mm strip has just been processed differently to make it easier to work with ? I asked the vendors and both claim is just press-rolled.
 
The more ductile sample probably had additional heat treatment (annealing) after cold rolling.
 
Most likely it's going to be a difference in temper. Take a look at Table5 in the link below to get an idea of how much difference this can make: the yield strength is the number that determines how hard it will be to bend. See there's a big range in the numbers for different grades: https://www.specialmetals.com/assets/smc/documents/alloys/nickel-duranickel/nickel-200-201.pdf

Also, if it's magnetic and you've ruled out iron/steel then there's not much else it can be. The only real posibility is one of the lower grades of stainless steel, which are magnetic.
 
It may be nickel 200 grade different condition (soft, half-hard, hard) or 200 versus 201 grade. Nickel 201 grade has low rate of work hardening.

Conductivity of stainless steel is of one order worse than nickel.
 
Good point about annealing. Both strips are magnetic, corrosion resistant (salt water test) and display similar electrical resistance. If you guys are correct and it is nickel in a different temper state, than the second vendor gets my instant recommendation: that ductile nickel is so much easier to work / cut / bend and weld. Hard to believe it's 0.2mm. But since I didn't trust my measuring stick, I did a weight check: 536g measured. Assuming the vendor sold me exactly 10m, the theoretical weight of that strip (actually a roll) would be: 3*0.02*1000(strip volume in cm3)*8.908(nickel density in g.cm-3)=534.48g. Given the plastic packing, that an almost suspiciously exact match...
 
If you want to be one hundred percent sure, or simply you are curious, find some scrap metal collector shop near you. They usually have handheld spectrometer for metal alloys identification. Strip width 28 - 30 mm and 0,15 – 0,2 mm thickness is more than enough for reliable analyse.

https://www.youtube.com/watch?v=NKv5rEKo17A

https://www.youtube.com/watch?v=fbaZbZFaIO4

https://www.youtube.com/watch?v=dZFl7TwmAwE
 
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